Abstract Background: Claudin-1, a tight-junction protein frequently overexpressed in colorectal cancer (CRC), is an attractive target for antibody-mediated near-infrared (NIR) fluorescence imaging. This study evaluates an anti-Claudin-1 antibody conjugated to IRDye800CW for detecting and validating colorectal tumors using bioluminescence correlation in orthotopic and metastatic mouse models. Methods: Luciferase-expressing LS174T human colon cancer cells were implanted into athymic nude mice to establish orthotopic (n = 10) and hepatic (n = 9) tumor models. Mice received 50 µg of Claudin-1-IRDye800CW intravenously 48 hours before imaging. In vivo imaging was performed using both the Pearl Trilogy Small Animal Imaging System and the Arthrex Synergy Vision System equipped for 800 nm fluorescence. Mean fluorescence intensity (mFI) was used to calculate tumor-to-background (TBR) and tumor-to-liver (TLR) ratios. Co-registration with luciferase bioluminescence was used to confirm probe specificity, and ex vivo imaging validated biodistribution. Results: In the orthotopic model, Claudin-1-IRDye800CW achieved a mean TBR of 3.92, clearly delineating tumor margins, while sub-millimeter peritoneal metastases (< 1 mm) produced a mean TBR of 2.9. In the hepatic model, the mean TLR was 3.42, confirming selective tumor contrast over surrounding tissue. Ex vivo analysis further increased contrast (TBR = 16.4; TLR = 4.78). Fluorescent signals consistently co-localized with luciferase activity, confirming targeting specificity. Both imaging systems demonstrated high-resolution detection, and the Arthrex clinical laparoscope enabled real-time intraoperative visualization under clinically relevant conditions. Conclusion: The anti-Claudin-1-IRDye800CW conjugate selectively and accurately identifies both primary and metastatic colorectal tumors in vivo. Strong tumor contrast and spatial concordance with bioluminescence validate its specificity, while compatibility with a clinical laparoscopic platform underscores the translational promise of Claudin-1-targeted NIR fluorescence imaging for colorectal cancer detection and fluorescence-guided surgery. Citation Format: Javier Bravo, Shanglei Liu, Siamak Amirfakhri, Blackberrie Eddins, Keita Kobayashi, Jasmin Zaker, Robert Hoffman, Sumbal Talib, Aaron M. Mohs, Punita Dhawan, Michael Bouvet. Near-Infrared Claudin-1 antibody enables accurate detection of primary and metastatic colorectal tumors in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2132.

Background/Aim: Recurrent head and neck squamous-cell carcinoma (HNSCC) is associated with poor prognosis and limited treatment options, particularly after failure of standard therapies including surgery, radiotherapy, chemotherapy, and immune checkpoint inhibitors. Methionine restriction has emerged as a novel clinical metabolic therapeutic strategy targeting the methionine addiction of cancer cells. The present patient report describes a case of recurrent tongue HNSCC that achieved complete remission with chemotherapy combined with methionine restriction. Case Report: A 35-year-old man was diagnosed with HNSCC of the left lateral border of the tongue (cT2N2bM0, Stage IVA). The patient underwent curative-intent surgery consisting of partial glossectomy and neck dissection. Despite multimodal treatment, including induction chemotherapy, salvage surgery, postoperative chemoradiotherapy, and subsequent immune checkpoint inhibitor therapy, the tumor recurred in the left submandibular region. Following further progression, combination chemotherapy with paclitaxel and cetuximab was administered in combination with methionine restriction (MR), consisting of a low-methionine diet and oral recombinant methioninase (rMETase), rMETase was produced using recombinant Escherichia coli expressing the methioninase gene from Pseudomonas putida and purified by standard methods. Tumor metabolic activity was evaluated using [18F]fluorodeoxyglucose positron-emission tomography (PET)/computed tomography (CT) performed according to standard clinical protocols. Rapid tumor regression was observed. Follow-up magnetic resonance imaging (MRI) and PET/CT demonstrated complete response, which was maintained after de-escalation to cetuximab combined with MR. Conclusion: The present case demonstrates the potential clinical efficacy of combining chemotherapy with MR in the treatment of recurrent HNSCC after curative-intent surgery and failure of standard therapies, including immune checkpoint inhibition. MR may represent a promising metabolic therapeutic approach for refractory HNSCC. Αdditional cases and prospective clinical trials are necessary.

INTRODUCTION:SGM-101, a near-infrared 700 nm emitting fluorophore-conjugated antibody targeting carcinoembryonic antigen, has shown promise in colorectal cancer (CRC) imaging. The present study determines whether colocalization of SGM-101 fluorescence excited at 700 nm and tumor luciferase expression can detect colon cancer micrometastases in orthotopic nude mouse models using the Pearl small animal preclinical imaging system and an FDA-approved (U.S. Food and Drug Administration) Arthrex Synergy Vision and exoscope clinical imaging system. MATERIALS AND METHODS:LS174T-luciferase human CRC cells were implanted in athymic mice to establish subcutaneous (n = 4) and orthotopic (n = 8) tumor models. Mice received 60 μg of SGM-101 intravenously 72 h prior to imaging and 4.5 mg of D-luciferin via intraperitoneal injection 10 min before imaging. Imaging was performed with the Pearl Trilogy System and the Arthrex Synergy Vision System and exoscope to detect SGM-101 tumor labeling and luciferase expression, including primary tumors and micrometastases. Colocalization of SGM-101 tumor labeling was determined by calculating tumor-to-background fluorescence ratios (TBRs). Biodistribution analysis and histologic confirmation were performed postmortem. RESULTS:SGM-101 fluorescence colocalized with tumor luciferase in both subcutaneous and orthotopic tumor models. Subcutaneous tumors showed TBRs of 3.54 and 2.51. Orthotopic tumors demonstrated strong labeling with an average TBR of 5.24 (±0.93). Microscopic peritoneal wall metastases (<1 mm) were detected by luciferase expression and SGM-101 fluorescence with both preclinical Pearl and clinical Arthrex imaging systems. Colocalization and biodistribution studies confirmed high tumor-specific uptake, with background signal found primarily in the liver. The Arthrex exoscope enabled clear real-time detection in the 700 nm channel, indicating that SGM-101 has clinical potential to detect primary colon cancer and metastatic tumors. CONCLUSIONS:The present study demonstrates that SGM-101 enables high-contrast tumor detection in CRC models and colocalizes with tumor luciferase expression and was able to detect colon cancer micrometastases ˂1 mm. The present findings suggest that SGM-101 labeling of tumors can be detected by preclinical as well as clinical imaging systems, demonstrating clinical potential for tumor staging and fluorescence guided surgery in the future.

BACKGROUND/AIM:Osteosarcoma is the most common malignant bone tumor in pediatric and young adult patients. Osteosarcoma is also refractory to immune checkpoint inhibitors (ICIs). It has been recently demonstrated that methionine restriction (MR) increases the response to ICIs in melanoma and colon cancer. The present study aimed to determine whether MR alone can be an immunotherapeutic for osteosarcoma. MATERIALS AND METHODS:K7M2 murine osteosarcoma cells and 143B human osteosarcoma cells were used for the present study. Cell viability and the half-maximal effective concentration (EC50) of methionine for K7M2 and 143B were determined with the WST-8 cell-viability reagent. Western immunoblotting was used to compare programmed cell death receptor ligand 1 (PD-L1) expression in K7M2 and 143B cells treated with and without MR. K7M2 cells were subcutaneously implanted in immunocompetent BALB/c mice and T-cell-deficient nude (nu/nu) mice to determine the efficacy of an MR diet on tumor growth and enhancing CD8-positive T-cell tumor infiltration in BALB/c mice. Tumor-infiltrating lymphocytes in the tumor of BALB/c mice were determined with immunohistochemistry. RESULTS:The EC50 values of methionine for K7M2 and 143B were 14.18 μM and 20.85 μM, respectively. Both cell lines had a strong dependence on methionine at the concentration range of 4 to 32 μM. MR using methionine-depleted medium in vitro decreased PD-L1 expression in 143B and K7M2, compared to untreated control cells (p<0.05, respectively). The MR diet significantly suppressed the growth of K7M2 tumors in immunocompetent BALB/c mice (p<0.05), but not in T-cell-deficient nu/nu mice. The MR diet enhanced CD8-positive T-cell infiltration in the K7M2 tumor growing in BALB/c mice (p<0.05). CONCLUSION:MR alone is a potential immunotherapeutic for osteosarcoma. The present results suggest MR is a T-cell stimulant and not a cause of T-cell exhaustion.

Since the discovery of nestin-expressing hair follicle-derived cells (NHFCs), they have attracted significant attention for regenerative medicine including neural-tissue engineering. The present study examines the gene expression profiles of NHFCs, focusing on neurotrophic factors and neural differentiation markers, and compares them to those of other well-characterized adult composite stem/progenitor cell systems, including bone marrow-derived mesenchymal cells, dental pulp-derived cells, as well as cortical astrocytes and hypothalamic neurons. The expression of key neurotrophic factors such as Bdnf, Ngf, Vegf, Ntf3, and Gdnf as well as neural-differentiation markers such as Nes, Sox10, Dcx, Tubb3, and Gfap are compared. The present study shows that NHFCs express significantly higher levels of Bdnf, Ngf, and Vegf compared to most of other evaluated cell types, indicating their potential neuroprotective properties. Additionally, NHFCs at passage 4 exhibit lower expression of Nes than the other cell types, suggesting a predisposition to differentiate into mature neuronal lineages. Elevated expression of Tubb3 in NHFCs further indicates the potential for neuronal maturation. The simultaneous expression of both neuronal and glial markers in NHFCs indicates their unique differentiation potential. The present study highlights the distinct molecular signature of NHFCs, suggesting their potential as a valuable resource for neuroregenerative therapies and other regenerative medicine applications.

Background/Aim:Methionine addiction (Hoffman effect) is a fundamental and general cancer hallmark targetable by methionine restriction, using methionine-depleted media or diet, or recombinant methioninase (rMETase). Our previous studies showed differential sensitivity of HCT-116 colon-cancer cells and Hs27 normal fibroblasts to rMETase in co-culture. The present study aimed to demonstrate the rescue conditions of cancer cells by methionine replenishment in the co-cultures of HCT-116 and Hs27 cells after rMETase treatment. Materials and Methods:Equal numbers of HCT-116 colon-cancer cells and Hs27 normal fibroblasts were co-cultured in 6-well plates in Dulbecco's modified Eagle's medium (DMEM). Two days after seeding, co-cultures were treated with rMETase at the HCT-116 IC50 (0.46 U/ml) or left untreated as controls. Growth of each cell type in co-culture was evaluated by phase-contrast microscopy on days 2, 4, 6, 8, 10, and 12 after treatment to assess the response to rMETase. On day 12, the existing medium in all wells was replaced with fresh DMEM containing methionine (methionine replenishment). Regrowth of HCT-116 and Hs27 was then assessed by phase-contrast microscopy 3, 6, and 9 days later. Results:In the untreated control group, HCT-116 cancer cells rapidly proliferated, and progressively overtook the Hs27 fibroblasts and predominated by day 12. In the rMETase-treated group, viable HCT-116 cells progressively decreased and were almost undetectable by day 12, whereas Hs27 cells remained viable throughout the observation period. After day-12 replenishment of methionine, previously rMETase-treated co-cultures showed reappearance of viable HCT-116 cells by day 3 and dominance over Hs27 cells by day 9. Conclusion:Continuous treatment with rMETase is necessary to maintain inhibition of cancer cells and normal-cell dominance in co-culture with cancer cells. These results have clinical implications indicating that methionine restriction must be continually maintained to inhibit cancer.

BACKGROUND/AIM:Bone metastasis of lung cancer is highly recalcitrant, and current treatment is palliative. Methionine addiction is a fundamental hallmark of cancer, known as the Hoffman effect, and is targeted by methionine restriction (MR). The present study aimed to evaluate the efficacy of MR combined with low-dose cisplatinum on an experimental nude-mouse model of bone metastasis of lung cancer. MATERIALS AND METHODS:The A549 human lung-adenocarcinoma cell line was used in the present study. An experimental bone-metastasis model was established by implanting A549 cells into the tibia of nude mice. The mice were then randomly assigned to four groups: untreated control; standard-dose cisplatinum (6 mg/kg, intraperitoneally, weekly); combination of low-dose cisplatinum (3 mg/kg, intraperitoneally, weekly) and an MR diet; and an MR diet only. Tumor growth and body weight were monitored during the 3-week treatment period. RESULTS:The combination of low-dose cisplatinum and an MR diet had the most tumor inhibition efficacy of all treatment groups, with tumors essentially being eradicated by the end of the treatment period. The combination of MR and low-dose cisplatinum showed superior efficacy compared to standard-dose cisplatinum. Furthermore, weight loss was observed only in the mice treated with standard-dose cisplatinum, whereas mice treated with the combination of low-dose cisplatinum and an MR diet maintained body weight comparable to that of the MR-alone group. CONCLUSION:MR enhanced the efficacy of low-dose cisplatinum, while mitigating treatment-associated toxicity in a lung-cancer experimental bone-metastasis model. The present findings suggest that metabolic targeting of methionine addiction is a promising therapeutic strategy enabling effective chemotherapy dose reduction in bone-metastatic lung cancer.

BACKGROUND/AIM:In the present study we compared the glucose and glutamine requirements of cancer and normal cells to determine if the Warburg effect is cancer specific. MATERIALS AND METHODS:143B human osteosarcoma, HT1080 human fibrosarcoma, HCT116 human colon cancer and normal Hs27 human fibroblasts were cultured in Dulbecco's modified Eagle's medium (DMEM) with and without glucose; with and without glutamine; or with and without methionine. The EC50 of glucose, glutamine and methionine was compared in cancer and normal cells. Co-culture of Hs27 normal fibroblast with each cancer cell line was performed by using 12-well plates with and without glucose or methionine. Cell viability was determined with the WST-8 viability reagent, by phase-contrast microscopy or fluorescence microscopy. RESULTS:The EC50 of glucose for the three cancer cell lines ranged from 0.54 to 4.88 mM. The EC50 of glucose for Hs27 normal fibroblasts was 0.35 mM, which was not significantly lower than in HCT116 cells (p=0.2225). The EC50 for glutamine ranged from 0.15 to 0.54 mM for the cancer-cell lines and 0.24 mM for normal fibroblasts, which did not distinguish normal from cancer cells. For comparison the EC50 of cancer cells for methionine ranged from 3.8 μM to 21.4 μM while for normal fibroblasts the EC50 for methionine was 2.3 μM, which was significantly lower than in all the cancer cell lines (p<0.0167). In co-culture of cancer and normal fibroblasts, glucose-free or glutamine-free medium resulted in loss of cell viability by day 7 for both the cancer and normal cells. In contrast, in methionine-free medium, the normal fibroblasts were alive and healthy at day 7. CONCLUSION:The Warburg effect of glucose and glutamine addiction is not cancer specific in comparison to methionine addiction (Hoffman effect), which is cancer specific, suggesting the Warburg effect is not a cancer paradigm.

BACKGROUND/AIM:To determine whether methionine restriction using recombinant methioninase (rMETase) enhances the efficacy of ultra-low-dose cisplatinum against lung cancer cells in vitro, and whether combining a methionine-restricted (MR) diet with low-dose cisplatinum can inhibit lung cancer growth in vivo with reduced toxicity. MATERIALS AND METHODS:Human A549 lung adenocarcinoma cells were treated with rMETase and cisplatinum in vitro. Cell viability was assessed after 72 hours using the WST-8 reagent. The IC50 value of rMETase was determined, and synergy was evaluated by combining rMETase at its IC50 with cisplatinum at its determined IC10-IC50. For in vivo analysis, A549 xenografts were established in nude mice and assigned to four groups: control: standard-dose cisplatinum [6 mg/kg, intraperitoneally (i.p.), weekly]; low-dose cisplatinum (3 mg/kg, i.p., weekly) + a methionine-restricted (MR) diet; or the MR diet alone. Treatments were administered for two weeks, with tumor size and body weight were monitored. RESULTS:For A549 lung-cancer cells the IC50 value of rMETase was 0.64 U/ml. Combination treatment with rMETase (IC50) and cisplatinum (IC10-IC50) synergistically reduced cell viability compared with either agent alone, even at the IC10 of cisplatinum. In vivo, A549 tumor eradication was observed only in the low-dose cisplatinum + MR diet group. Standard-dose cisplatinum alone and MR-alone showed delayed or limited efficacy. Body-weight loss was minimal in the low-dose cisplatinum + MR group compared with the standard-dose cisplatinum group, indicating reduced systemic toxicity. CONCLUSION:Methionine restriction enhances the efficacy of ultra-low-dose cisplatinum on lung cancer cells in vitro. Low-dose cisplatinum in combination with an MR diet prevented lung-cancer growth in nude mice. The present approach of cancer therapy may help reduce platinum-related toxicity and improve treatment outcomes, suggesting further investigation for clinical translation.

BACKGROUND/AIM:Recently, there have been numerous publications on the induction of ferroptosis by cysteine restriction in cancer cells. The present report aimed to determine whether cysteine restriction (CR) is a cancer-specific vulnerability in comparison with methionine restriction (MR), which is a known cancer-specific vulnerability. MATERIALS AND METHODS:Human cancer cell lines (HCT116 colon cancer, 143B osteosarcoma or HT1080 fibrosarcoma) and normal human fibroblasts (Hs27) were cultured in Dulbecco's modified Eagle's medium (DMEM) with dialyzed fetal bovine serum from which methionine or cysteine or both or neither had been depleted. Cancer and normal cells were co-cultured in 12-well plates under the above conditions. HCT116 cells expressing green fluorescent protein, and 143B and HT1080 cells expressing red fluorescent protein, were visualized by fluorescence microscopy. Normal fibroblasts and cancer cells were visualized by phase-contrast microscopy as well. RESULTS:In co-culture, of either 143B, HCT116 or HT1080 with Hs27 human fibrosarcoma, CR was toxic to Hs27 normal fibroblasts as well as to all three cancer cell lines. In contrast, MR was toxic only to the cancer cells but not normal fibroblasts. Dual CR and MR was toxic to normal and cancer cells. CONCLUSION:For all three cancer cell lines, HCT116 colon cancer, HT1080 fibrosarcoma and 143B osteosarcoma, both MR and CR were highly inhibitory in the co-cultures with Hs27 normal fibroblasts. In all cases MR had only a slight effect on normal fibroblasts, but CR was highly toxic to normal fibroblasts. Thus, MR is a cancer-specific vulnerability in contrast to CR which is toxic to both normal and cancer cells and is not a cancer-specificity vulnerability. Therefore, attempting to induce ferroptosis of cancer cells by CR does not appear to have potential as an effective cancer therapy.

BACKGROUND/AIM:The present study aimed to investigate the association between sleep duration and the risk of newly-onset cancer among middle-aged and elderly adults, and to examine the effect of depression on this association. PATIENTS AND METHODS:The data from 9,400 participants in the China Health and Retirement Longitudinal Study (CHARLS, 2011-2020) were analyzed. Cox proportional hazards regression models, Kaplan-Meier survival curves, restricted cubic spline (RCS) regression, and threshold-effect analysis were employed to evaluate the relationship between sleep duration and cancer risk. Furthermore, subgroup analyses were conducted to explore potential heterogeneity across populations. RESULTS:Over a median follow-up period of 9.0 years, 271 participants (2.9%) developed newly-onset cancer. Longer sleep duration was associated with a reduced risk of incident cancer [fully adjusted hazard ratio (HR)=0.65, 95% confidence interval (CI)=0.51-0.84]. RCS regression indicated a nonlinear association between sleep duration and the risk of cancer incidence (nonlinearity p=0.005), with an inflection point at 5.0 h of sleep per night. Specifically, sleeping ≥5 h per day was associated with an 18% lower risk of cancer (HR=0.82, 95% CI=0.74-0.91), whereas shorter sleep duration (<5 h) showed no significant protective effect. This protective effect of sleep was more pronounced among individuals with depression (HR=0.64, 95% CI=0.44-0.92). Subgroup analyses further revealed that the protective effect of sleep was stronger among men, urban residents, individuals without hypertension, and smokers. CONCLUSION:Longer sleep duration (≥5 h) is independently associated with a lower risk of newly-onset cancer in middle-aged and elderly adults, particularly in those with depression. These findings highlight the importance of sleep health for cancer prevention.

BACKGROUND/AIM:Extracellular vesicles (EVs), including exosomes, are abundant in body fluids, and EV surface proteins can be profiled as potential minimally invasive biomarkers. CD147 (EMMPRIN/Basigin) is a tumor-associated surface glycoprotein implicated in cancer progression. CD9 and CD63 are tetraspanin membrane proteins widely used as EV markers. The present study aimed to evaluate the clinical significance of serum EV subsets double-positive for CD9 and CD63, or for CD9 and CD147 in patients with colorectal cancer (CRC) before and after tumor resection. MATERIALS AND METHODS:Sixteen patients with CRC were recruited, and paired pre- and postoperative serum samples were analyzed for CD9+ CD63+ EVs and CD9+ CD147+ EVs. Serum EVs were quantified using the ExoCounter system with antibody-conjugated beads. CD147 expression in resected tumor tissue was analyzed by immunohistochemistry. RESULTS:CD9+ CD63+ EVs were significantly reduced in postoperative samples compared with preoperative samples (p=0.0151). CD9+ CD147+ EVs also showed a significant postoperative decrease (p=0.0186). CD147 immunostaining was positive in 13 out of 16 resected tumors (81.3%). In patients with CD147 negative tumors (n=3), serum CD9+ CD147+ EV levels were low at both pre- and postoperative time points and remained unchanged. CONCLUSION:Serum CD9+ CD63+ and CD9+ CD147+ EV subsets decreased after CRC surgery, supporting their potential utility as minimally invasive liquid biopsy biomarkers of postoperative tumor burden. Future prospective clinical trials will determine whether these EV subsets are indeed biomarkers of postoperative residual tumor.

The standard treatment for medullary thyroid cancer (MTC) is total thyroidectomy with cervical lymph node dissection. Cure depends on complete surgical resection; however, intraoperative identification of tumor margins and involved lymph nodes remains challenging. The CEA-expressing MTC cell line TT was used to establish orthotopic thyroid tumor models (n = 7), whereas the non-CEA-expressing papillary thyroid cancer (PTC) cell line TPC-1 was used to establish subcutaneous negative control tumor models (n = 3). Orthotopic MTC models were established by injecting TT cells (1x107) into the thyroid gland of athymic nude mice, whereas subcutaneous models were established by implanting TT and TPC-1 tumors into the flanks of nude mice. The humanized anti-CEA antibody M5A was conjugated to the near infrared fluorophore IRDye800CW to generate M5A-IR800. Mice received 50 µg of M5A-IR800 via tail vein injection and were imaged under bright light and fluorescence using a LI-COR Pearl Imaging System. Tumor-to-background ratios (TBR) were calculated as the ratio of mean tumor fluorescence intensity to surrounding tissue. Tumor specimens were analyzed by histology and immunohistochemistry. The mean TBR of orthotopic MTC tumors treated with M5A-IR800 was 6.85 (±3.75) at 96 hours post injection. Mice bearing subcutaneous TT tumors also achieved high TBRs of 4.23, 3.59, and 3.3 at 96 hours. In contrast, non-CEA-expressing TPC-1 tumors demonstrated no detectable fluorescence. Hematoxylin and eosin staining and immunohistochemistry confirmed accurate tumor targeting by M5A-IR800 and strong CEA expression in MTC tumors. M5A-IR800 specifically and brightly targets MTC in preclinical mouse models and represents a promising approach to enhance intraoperative visualization of MTC.

Abstract Introduction: The purpose of the present study is to validate the use of an anti-MUC4 antibody conjugated near infrared dye to target primary and metastatic gastric cancers in nude mouse models. Methods: Subcutaneous models were created in nude mice by injecting 106 cells of human gastric cancer cell lines SNU-16 or NCI-N87 into their flanks. These tumors were excised after 2 months and 1 mm3 fragments were implanted into the stomachs of nude mice to establish orthotopic gastric cancer models of SNU-16 and NCI-N87. Experimental metastasis models were established by injecting 106 SNU-16 or 106 NCI-N87 cells intraperitoneally in nude mice. 2-3 months after tumor implantation mice were injected via tail vein with a mucin4 antibody conjugated to a near infrared fluorescent dye IRDye800CW (MUC4-IRDye800CW). Mice were sacrificed 72 hours after tail vein injection of 50 µg MUC4-IRDye800CW and imaged with the LI-COR Pearl Imaging System and a Stryker laparoscope. The tumor-to-background ratios (TBR) were calculated by dividing the mean fluorescence intensity of the tumors by that of the surrounding stomach. Histopathological analysis was performed on tumors with immunohistochemical (IHC) staining with anti-mucin-4 and anti-immunoglobulin G (IgG) as a negative control. Results: 20 total mice were imaged, including 14 primary gastric cancer models and 4 intraperitoneal metastatic gastric cancer models. Primary gastric SNU-16 tumors (n = 6) had a mean TBR of 1.99 (SE ± 0.58), and primary gastric NCI-N87 tumors (n = 8) had a mean TBR of 2.81 (SE ± 1.04). Metastatic SNU-16 tumors (n = 3) had a mean TBR of 3.7 (SE ± 0.75), and metastatic NCI-N87 tumors (n = 3) had a mean TBR of 3.91 (SE ± 0.98). Tumor borders were clearly visualized with both Pearl and the Stryker laparoscope fluorescence imaging systems. Representative tumors stained with anti-mucin-4 stained brown while those stained with anti-IgG did not. Conclusions: Anti-MUC4-IRDye800CW can be used to accurately localize both primary and metastatic gastric cancer models in nude mice with fluorescence imaging and is promising for identifying both primary tumor margins and intraperitoneal metastasis intra-operatively. Citation Format: Blackberrie Eddins, Sunidhi Jaiswal, Abhijit Aithal, Siamak Amirfakhri, Javier Bravo, Jasmin Zaker, Sumbal Talib, Kavita Bantwal Mallya, Aaron M. Mohs, Maneesh Jain, Robert M. Hoffman, Surinder K. Batra, Michael Bouvet. Targeting primary gastric tumors and peritoneal metastases in cell-derived xenograft mouse models using an anti-mucin-4-antibody conjugated near infrared fluorophore [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2134.

Positive surgical margins (PSMs) are a major predictor of recurrence in thyroid cancer; however, their intraoperative detection remains challenging, particularly for microscopic PSMs. This study aimed to demonstrate that a sprayable pH-sensitive near-infrared fluorescent probe (PH10) could specifically and robustly label thyroid tumors in orthotopic mouse models. The pH sensitivity, cytotoxicity, and cellular uptake mechanisms of PH10 were evaluated in papillary thyroid carcinoma (K1) and anaplastic thyroid carcinoma (8505C) cell lines in vitro. Orthotopic thyroid cancer mouse models were then established using both K1 and 8505C cells. In vivo fluorescence following topical spraying of PH10 was quantified after sequential washes to assess tumor-to-background ratios. Fluorescence-guided surgery (FGS) was performed to determine whether PH10 could facilitate complete resection of orthotopically grown thyroid tumors. Complete resection was validated by hematoxylin and eosin histology. PH10 demonstrated low cytotoxicity at clinically relevant concentrations in vitro and showed selective uptake into thyroid cancer cells, predominantly via organic anion transporting polypeptide-mediated transport. Topical spraying of PH10 in orthotopic thyroid cancer mouse models established from K1 and 8505C cell lines generated strong tumor-specific fluorescence. Tumor-to-background ratios were significantly higher than background and remained distinguishable after multiple washes. In both models, PH10 enabled visualization of macroscopic residual tumors and detection of microscopic PSMs, with fluorescence patterns closely corresponding to histologic findings. FGS enabled complete tumor resection, as confirmed by fluorescence and histology. In conclusion, topical application of PH10 provides rapid, tumor-specific fluorescence suitable for identifying PSMs and facilitating complete tumor resection by FGS in thyroid cancer.

BACKGROUND/AIM:The phosphatidylinositol 3-Kinase (PI3K) pathway is thought to be oncogenic in cancers when it is mutated at various sites. However, drugs targeting this mutated pathway have had only modest efficacy. Recently, a new inhibitor targeting the PI3K pathway, inavolisib (IVB), has been developed. In the present study, we determined whether IVB is synergistic with recombinant methioninase (rMETase) on breast-cancer cells compared to normal fibroblasts. MATERIALS AND METHODS:Cell viability was determined using the WST-8 cell-viability assay. The half-maximal inhibitory concentrations (IC50) of IVB and rMETase were determined on MCF-7 human breast-cancer cells compared to Hs-27 human normal fibroblasts in vitro. The efficacy of rMETase combined with IVB, at their respective IC50 values, on MCF-7 breast-cancer cells and Hs-27 normal fibroblasts was evaluated. RESULTS:The IC50 of IVB on MCF-7 breast-cancer cells of 83 nM was significantly lower than the IC50 on Hs-27 normal fibroblasts, which was 8.8 μM. The combination of rMETase and IVB was synergistic on MCF-7 breast-cancer cells, resulting in an inhibition of 76.2%. In contrast, the combination of rMETase and IVB was not synergistic on Hs-27 normal fibroblasts. CONCLUSION:IVB had a very low IC50 on MCF-7 breast-cancer cells compared to Hs-27 normal fibroblasts. IVB had increased efficacy on MCF-7 breast-cancer cells when combined with rMETase, showing strong synergy. In contrast, the combination of rMETase and IVB showed no synergy on Hs-27 normal fibroblasts. Therefore, IVB in combination with rMETase has strong clinical potential for breast cancer and possibly other cancers.

BACKGROUND/AIM:Glutamine (GLN) addiction has been proposed as a cancer vulnerability and a therapeutic target. However, the glutamine requirement of normal cells is poorly understood. In the present study, we used a unique co-culture model to study the glutamine requirement of cancer cells compared to normal cells co-cultured together. MATERIALS AND METHODS:The human fibrosarcoma cell line HT1080 and normal human fibroblasts HS27 were co-cultured in 12-well dishes seeded with equal numbers of cells of each type. Additionally, HS27 cells were cultured alone in 6-well plates. The cells were grown in Dulbecco's Modified Eagle's Medium (DMEM) which did not contain GLN, methionine (MET), or cystine (CYS). 150 μM L-cystine 2HCl was added to all media. Co- and mono- cultures were grown under the following conditions: Complete medium (GLN 4 mM and MET 100 μM); MET restriction [Methionine restriction (MR), GLN 4 mM and MET 0 μM]; GLN restriction [Glutamine restriction (GR), GLN 0 mM and MET 100 μM] and MR+GR (GLN 0 mM and MET 0 μM). Cells were observed under phase-contrast and fluorescence microscopy for seven days. ImageJ was used to compare the three groups: MR, GR and MR+GR. RESULTS:In complete DMEM, HT1080 fibrosarcoma cells dominated HS27 normal fibroblasts in co-culture. Under MR, HT1080 cells became mostly non viable, but HS27 cells remained viable. Under GR and MR+GR, both HT1080 and HS27 cells became mostly non-viable. Monoculture experiments showed that normal cells survived under MR but not GR. CONCLUSION:GR is not a cancer-specific vulnerability, while MR is. Therefore, GR is not a promising cancer-therapy strategy.

BACKGROUND/AIM:Accurate preoperative staging is important for predicting prognosis and determining appropriate preoperative treatment. We retrospectively examined the prognostic impact of preoperative staging based on sizes of metastatic lymph nodes (LNs) in pStage II/III sigmoid and rectosigmoid (RS) colon cancer. We investigated the correlation of sizes of metastatic LNs with levels of methylation of the SOX11 gene in circulating tumor DNA (ctDNA). PATIENTS AND METHODS:The subjects were 353 patients with sigmoid and RS colon cancer. Patients in which the preoperative stage diagnosis was the same as the postoperative pathological diagnosis were classified as Group E, and those in which the preoperative stage diagnosis was underestimated compared to the postoperative pathological diagnosis were classified as Group U. The ctDNA methylation levels of the SOX11 gene were assessed with the quantitative methylation-specific polymerase chain reaction. RESULTS:pT3N+ patients had significant differences in recurrence-free survival (RFS) between Groups E and U (p=0.01). The Relative Methylation Values (RMVs) for the SOX11 gene in patients with a short diameter <4 mm were significantly lower than in patients with a short diameter ≥4 mm (p=0.03). pT3 pStage III patients in which the N factor was understaged in preoperative clinical diagnosis had a favorable RFS. Patients with a short LN diameter (≤4 mm) had lower RMVs in ctDNA and longer RFS. CONCLUSION:The methylation level of the SOX11 gene in ctDNA predicts RFS and affords more accurate prognostication than radiological staging based on LN size in pStage II/III sigmoid and RS colon cancer. The present results suggest that the extent of methylation of the SOX11 gene in ctDNA can serve as a prognostic biomarker of RFS of patients with pStage II/III sigmoid and RS colon cancer.

Background/aimIvermectin is emerging as a potential anticancer agent. Recombinant methioninase (rMETase) targets methionine addiction of cancer and shows synergistic efficacy when combined with cancer-chemotherapy drugs. In the present study, we compared the efficacy of the rMETase combination with ivermectin versus rMETase combined with each of five first-line chemotherapeutic agents, on HCT116 human colon-cancer cells.Materials and methodsThe half-maximal inhibitory concentrations (IC50) of rMETase, ivermectin, and five first-line chemotherapy drugs were determined from dose-response curves. HCT116 colon-cancer cells were then treated with each drug at its IC50 concentration, either alone, or in combination with rMETase, at their IC50 concentration. Cell viability was assessed after 72 h using the WST-8 assay. A chemosensitivity index (CI) was defined as the ratio of cancer-cell viability after treatment with each drug alone at its IC50 to that after treatment with the same drug at its IC50 concentration combined with rMETase.ResultsAt the IC50 concentration, ivermectin combined with rMETase (CI, 6.7 ± 1.9) was significantly (p < 0.05) more effective than rMETase combined with 5-fluorouracil (CI, 2.0 ± 0.7); cisplatinum (CI, 2.4 ± 1.5); gemcitabine (CI, 2.5 ± 0.7); and paclitaxel (CI, 2.8 ± 0.5). Only doxorubicin combined with rMETase was slightly more effective than rMETase combined with ivermectin (CI, 7.8 ± 1.7).DiscussionIvermectin combined with rMETase was more effective than four of five first-line chemotherapy drugs combined with rMETase against colon-cancer cells, demonstrating additional promise of ivermectin as an anticancer drug.

Background/Objectives: The majority of thyroid cancer patients are diagnosed with papillary thyroid cancer. A complete R0 resection significantly lowers cancer recurrence risk for high-risk papillary thyroid cancer but can be difficult to achieve because tumor margins are not easily visualized. The purpose of the present narrative review is to describe current work and future directions in fluorescence-guided thyroid cancer surgery. Methods: PubMed and Google Scholar were used to identify 45 articles that focused on fluorescence labeling and imaging of thyroid cancer published through February 2026 using the search terms “thyroid cancer” AND (“fluorescence imaging,” OR “NIR imaging” OR “optical imaging”) OR “fluorescence guided thyroidectomy”. Standalone abstracts and publications not available in English were excluded. Results: 17 fluorescent probes were shown to visualize tumor margins and micrometastases, 3 probes were able to visualize nerves, and 2 probes targeted lymph nodes. Most studies were done using animal models. Two probes (EMI-137, which targets tumors, and bevonescein, which targets nerves) were tested in clinical trials with good safety profiles. Conclusions: Several tumor-targeted fluorophores and optical imaging strategies have shown promise for thyroid cancer localization, margin assessment, lymph node evaluation, and nerve visualization; however, most remain preclinical, and clinical utility will require standardized dosing, imaging thresholds, safety assessment, and outcome-based validation with multicenter clinical trials.