Metastatic colorectal cancer (mCRC) differs clinically based on RAS and BRAF mutations or DNA methylation. However, in mCRC, the prognostic value and biological characteristics of genome-wide DNA methylation status (GWMS) in each RAS/BRAF genotype is unknown. To clarify this, primary tumor samples from patients with informed consent in the phase III TRICOLORE study were collected, and RAS and BRAF mutations, immunohistochemical staining of mismatch repair-related proteins, comprehensive gene expression, and genome-wide DNA methylation were analyzed. The tumor samples were classified into high-methylated colorectal cancer (HMCC) and low-methylated colorectal cancer (LMCC). Gene set enrichment analysis (GSEA) was conducted using microarray data. A total of 226 patients were included and classified into the RAS/BRAF wild-type (wt) (n = 125), RAS mutant (mt) (n = 87), and BRAF mt (n = 14), of whom 22 (17.6%), 30 (34.5%), and 14 (100%) had HMCC. HMCC exhibited significantly worse overall survival (OS) than that of LMCC in the RAS/BRAF wt group but not in the RAS mt group. In GSEA, RAS/BRAF wt HMCC was associated with microsatellite instability and BRAF V600E mutation. The poor prognosis of RAS/BRAF wt HMCC may be attributed to gene expression patterns associated with microsatellite instability and BRAF V600E mutation.

TPS280 Background: For metastatic colorectal cancer, clinical benefit of anti-EGFR monoclonal antibody (mAb) has been limited to patients (pts) with RAS / BRAF wild-type (wt) left-sided tumors. The role of such therapy for right-sided (RS) metastatic colon cancer remains unclear, particularly in the first-line setting. We previously demonstrated that DNA methylation status (DMS) may influence the efficacy of anti-EGFR mAb + irinotecan in the third-line or later setting: the low-methylated colorectal cancer (LMCC) responded better to anti-EGFR mAbs than high-methylated colorectal cancer (HMCC), irrespective of primary tumor location. We thus hypothesize that even in RS metastatic colon cancer, pts with LMCC may derive greater clinical benefit from anti-EGFR mAb + chemotherapy compared to bevacizumab + chemotherapy in the first-line setting. Methods: The T-CORE2401 is a multicenter, randomized, phase II trial comparing the efficacy and safety of mFOLFOX6 + cetuximab (Cet arm) vs. mFOLFOX6 + bevacizumab (Bev arm) in RAS / BRAF wt RS metastatic colon cancer. Pts will be stratified by DMS determined by OncoGuide EpiLight Methylation Detection Kit (Riken Genesis) into the LMCC or HMCC groups. Key eligibility criteria include: (1) Histologically confirmed unresectable, metastatic adenocarcinoma of the RS colon (cecum to splenic flexure; appendix excluded), (2) No prior systemic chemotherapy, (3) Confirmed RAS / BRAF wt status, (4) ECOG performance status 0–1, (5) Age ≥20 years, and (6) At least one measurable lesion per RECIST v1.1. The primary endpoint is objective response rate (ORR) in the LMCC group. Secondary endpoints include overall survival, progression-free survival, early tumor shrinkage, depth of response, and safety in both LMCC and HMCC groups. Assuming an ORR of 63.6% in the Bev arm, the study is powered to detect an ORR of 81.8% in the Cet arm within the LMCC group (two-sided α = 0.20; β = 0.3), requiring 80 pts (40 per arm) in the LMCC group. The ratio of LMCC to HMCC is expected to be 3:1, and a total of 110 pts will be enrolled. Biomarker analyses will include serial blood sampling and circulating tumor DNA analyses to monitor genomic and epigenomic alterations. Enrollment for the study began in June 2025 (jRCT 1021240067). Clinical trial information: 1021240067 .

Biobanks are extremely important research platforms that enable the development of diverse medical research projects by providing large numbers of biological samples and associated clinical information. Tohoku University Hospital (TUH) took the initiative to establish the Tohoku University Clinical Biobank (TUCB), which operates in cooperation with the Tohoku Medical Megabank Organization (ToMMo), a population-based biobank. TUCB has been managed by the Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), primarily by cooperation with ToMMo and the Personalized Medical Center (P-MEC) of TUH. TUCB is located on the ToMMo premises and leveraging the high-quality management expertise honed at ToMMo, collects diverse samples from patients undergoing treatment at TUH. By the end of March 2024, 29 clinical departments at TUH have participated. These biospecimens are procured from more than 10,000 participants and informed consent has been obtained by doctors as well as Genomics and Medical Research Coordinators (GMRCs). The collected biospecimens include blood and tissue samples, peripheral blood- and bone marrow-derived mononuclear cells, liquid biopsies, oral samples, mucus samples of gastrointestinal tract, urine, and stool samples. Our repository houses nearly 10,000 tissues, over 120,000 blood samples, and more than 10,000 other sample types. TUCB has shared over 10,000 high-quality biospecimens with various studies. We conduct genome and multi-omics analyses in-house through collaborations with various cross-divisional INGEM groups. TUCB represents a new style of disease-based biobank that collaborates with population-based biobank and analysis departments, plays a crucial role in advancing clinical sciences, and will significantly contribute to the realization of precision medicine.

Cancer genomic medicine interprets genetic information for diagnosis and treatment. It requires an organized team of experts from various fields to discuss treatment recommendations at a molecular tumor board (MTB). It is also important to track patient outcomes based on these decisions and seamlessly incorporate them into future discussions at the MTB. We developed a system to manage the MTB efficiently. Using this system, we followed the outcome and prognosis of 1643 patients whose treatment was discussed at the MTB and evaluated the utility of a realistic comprehensive genomic profiling (CGP) test. Treatment recommendations were made for 240 patients (14% of the total cases). Of these, 118 (7% of the total) were treated with the drugs recommended by the MTB. The cancer type with the highest percentage of patients in which treatment recommendations were made and drugs were administered was thyroid cancer, followed by breast cancer, lung cancer, prostate cancer, and cholangiocarcinoma. While cancer-specific overall survival was inconclusive due to few cases, CGP-recommended treatment significantly extended patient survival from the CGP test date. This analysis, utilizing our patient follow-up system, suggests that CGP testing expands treatment options for a subset of patients and may improve treatment efficacy.

Li-Fraumeni syndrome (LFS) is a hereditary cancer-predisposing disorder caused by germline pathogenic variants in the TP53 gene. Attenuated LFS represents a clinically milder form characterized by lower penetrance and later tumor onset, evading standard diagnostic criteria. We report a case of a 36-year-old Japanese woman who presented with hematochezia and was diagnosed with metastatic rectal adenocarcinoma. After failure of the first- to third-line chemotherapies, plasma-based comprehensive genomic profiling (CGP) was performed. The assay revealed a TP53 p.R181H variant (allele frequency: 0.512), KRAS p.G12D variant, PIK3CA p.E545K variant, and a CTNNB1 splicing variant. Family history included multiple gastrointestinal and hematological malignancies in first- and second-degree relatives. Germline testing confirmed heterozygosity of TP53 p.R181H, a temperature-sensitive variant suggested to have reduced penetrance. Notably, this variant is relatively common in European populations but rare in East Asian cohorts. To the best of our knowledge, this is the first reported East Asian case of attenuated LFS associated with the TP53 p.R181H variant. This case underscores the broader phenotypic spectrum of LFS. With the growing use of CGP, LFS may be identified more frequently in East Asia, potentially revealing attenuated LFS missed by traditional diagnostic criteria.

PURPOSE:Cetuximab plus paclitaxel (CET + PTX) is frequently administered after immune checkpoint inhibitor (ICI) therapy in patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M-HNSCC). However, the relation between responses to these two treatment lines has remained unclear. We aimed to clarify this relation and its potential mechanisms, focusing on the patients treated with pembrolizumab plus chemotherapy and subsequent CET + PTX. PATIENTS AND METHODS:We retrospectively reviewed patients with R/M-HNSCC who received pembrolizumab plus chemotherapy and subsequent CET + PTX at Tohoku University Hospital between April 2020 and November 2025. Clinical outcomes of CET + PTX were assessed according to response to prior pembrolizumab plus chemotherapy. Gene expression and immunohistochemical (IHC) analyses of pretreatment tumor samples, as well as HNSCC cell-based assays, were performed. RESULTS:This study included 30 patients. The overall response rate (ORR) to subsequent CET + PTX was 57%. The ORR and progression-free survival (PFS) of CET + PTX were significantly greater in patients who showed progressive disease on pembrolizumab plus chemotherapy than in responders (P < .01). Gene expression analyses revealed enrichment of Janus kinase (JAK)-STAT signaling pathways in pembrolizumab plus chemotherapy nonresponders who responded to CET + PTX. Consistently, high tumor expression of phosphorylated STAT3 was observed exclusively in this subgroup by IHC. CET sensitivity across HNSCC cell lines correlated with STAT3 phosphorylation. CONCLUSION:Responses to pembrolizumab plus chemotherapy and subsequent CET + PTX were inversely associated in R/M-HNSCC. Activation of the JAK-STAT signaling pathway, particularly STAT3 phosphorylation, may identify tumors resistant to pembrolizumab plus chemotherapy but sensitive to CET + PTX, thereby guiding post-ICI treatment selection.

BACKGROUND:Oxaliplatin, a third-generation platinum-based chemotherapeutic agent, is widely used in the treatment of colorectal cancer (CRC). However, some patients do not respond effectively to oxaliplatin, and intrinsic resistance to the drug poses a significant challenge. Recent studies have revealed an association between the gut microbiome and the progression of CRC. We hypothesized that Citrobacter freundii, a component of the gut microbiome, contributes to oxaliplatin resistance by regulating specific gene expression in CRC cells. METHODS:A bacterial culture filtrate from Citrobacter freundii was employed in the experiments. The CRC cell line RKO, following exposure to this filtrate, was analyzed using high-throughput RNA sequencing. Candidate genes were identified through MTT assays, siRNA knockdown, and overexpression experiments. Apoptosis and reactive oxygen species (ROS) assays were performed to investigate the underlying mechanisms. Finally, a xenograft mouse model was used to evaluate oxaliplatin resistance in vivo. RESULTS:Exposure to bacterial culture filtrate from Citrobacter freundii induced oxaliplatin resistance in RKO cells with downregulation of the NINJ2 gene as a possible molecular mechanism. ReducedNINJ2 gene expression suppressed oxaliplatin-induced apoptosis and ROS generation. A tendency toward reduced oxaliplatin efficacy was observed in vivo when NINJ2 gene expression was suppressed. CONCLUSION:This study demonstrates that Citrobacter freundii promotes oxaliplatin resistance in CRC through downregulation of NINJ2 gene. NINJ2 gene may serve as a predictive biomarker and therapeutic target to overcome oxaliplatin resistance in CRC.

Epigenetic alterations, including DNA methylation, significantly contribute to colorectal cancer (CRC); the gut microbiota is also involved. However, studies on the possible role of microbiota in DNA methylation are limited. This study investigates the association between gut microbiota composition and high-methylated CRC (HMCC). Fecal and tumor tissue samples were collected from 86 patients with sporadic CRC. HMCC was defined based on the methylation status of 16 CpG sites of tumor-derived genomic DNA. 16S rRNA gene sequencing was performed to reveal the composition of the gut microbiota. The load of Fusobacterium nucleatum (F. nucleatum) in tumor tissues was assessed using quantitative polymerase chain reaction (qPCR). HMCC was identified in 21 patients, whereas 65 were classified as having low-methylated CRC (LMCC). HMCC was significantly associated with proximal location, large diameter, undifferentiated histology, and high frequency of BRAF mutation. In gut microbial analyses, the relative abundances of 84 bacteria, including F. nucleatum, were significantly different between HMCC and LMCC. The load of F. nucleatum in CRC specimens was significantly correlated with its relative abundance in fecal samples and tended to be enriched in HMCC tissues. This study characterizes the gut microbiota profile in HMCC and suggests that bacteria, such as F. nucleatum, may contribute to HMCC pathogenesis through DNA methylation. Further studies are needed to determine whether the microbiome acts as a promoter or bystander in HMCC development.

BACKGROUND:The TP53 signature determined using a biopsy specimen before neoadjuvant chemotherapy (pre-NAC biopsy specimens) predicts NAC response and prognosis in breast cancer. We aimed to compare the clinical utility of the TP53 signature determined using pre-NAC biopsy specimens and surgical specimens after NAC (post-NAC surgical specimens). METHODS:This observational cohort study included patients with paired pre-NAC biopsy and post-NAC surgical specimens, analyzing the association between the TP53 signature from each specimen and prognosis (UMIN000042055). RESULTS:Pre-NAC biopsy specimens classified 71 patients into those having a TP53 mutant signature (pre-mt, n = 47) and wild-type signature (pre-wt, n = 24), with the same for post-NAC surgical specimens (post-mt, n = 16 and post-wt, n = 55). Among the 47 pre-mt patients, 31 became post-wt (pre-mt/post-wt), whereas 16 remained post-mt (pre-mt/post-mt). All pre-wt patients remained post-wt (pre-wt/post-wt). Recurrence-free survival (RFS) was significantly shorter in the pre-mt group than in the pre-wt group, although no significant difference was observed between the post-mt and post-wt groups. Change in the TP53 signature following NAC did not affect predictive ability of the TP53 signature determined using pre-NAC biopsy specimens. CONCLUSIONS:The TP53 signature status should be determined using pre-NAC biopsy specimens.

Epigenetic regulation mechanisms such as deoxy ribonucleic acid (DNA) methylation are important for controlling various biological phenomena by regulating gene expression at the genome level. Epigenetic abnormalities are associated with the onset of diseases including cancers. Aberrant DNA methylation is an important epigenetic change in the development and progression of colorectal cancer. DNA methylation in tumor tissues occurs mainly in CpG islands in the promoter regions of genes and inactivates gene functions by negatively suppressing transcription. The CpG island methylator phenotype (CIMP) is an important carcinogenic mechanism in colorectal cancer related to DNA methylation and is involved in approximately 20% of all colorectal cancers. However, CIMP does not always represent the genome-wide DNA methylation status in colorectal cancer. We developed a new method to assess genome-wide DNA methylation status and showed that it is a predictor of the efficacy of anti-estimated glomerular filtration rate (EGFR) antibody drugs and a prognostic factor. This new method has received regulatory approval as a new in vitro diagnostic for predicting sensitivity to anti-EGFR antibody drugs in colorectal cancer.

Background Appendiceal carcinoma (AC) is a rare malignancy and has distinct genomic features, but their impact on prognosis and chemotherapy efficacy requires further investigation. Methods This retrospective study analyzed patients with advanced AC from the Japanese nationwide comprehensive genomic profiling test database, the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database, focusing on genetic alterations and their associations with clinical outcomes. Results Of the 314 patients, the histological types Queryincluded adenocarcinoma (Ad) (51.9%), mucinous adenocarcinoma (MAd) (30.3%), goblet cell adenocarcinoma (12.4%), and signet-ring cell adenocarcinoma (5.4%). The most common mutations were KRAS (52.5%), TP53 (49.4%), SMAD4 (18.8%), and GNAS (17.2%). KRAS mutations were most frequent in MAd (68.4%) and Ad (58.9%), whereas TP53 mutations were mostly prevalent in Ad (62.6%). We classified patients into molecular subtypes based on the presence of mutations and analyzed differences in overall survival (OS) by molecular subtype. Patients with TP53 -mutant (mut) dominant tumors (all TP53 -mut) and KRAS -mut focused tumors ( TP53 -wild-type (wt)/ GNAS -wt/ KRAS -mut/any SMAD4 ) showed a poorer median OS compared with those with GNAS -mut focused tumors ( TP53 -wt/ GNAS -mut/any KRAS /any SMAD4 ) (median 47.4 and 37.5 months vs. not reached; p = 0.01 and p = 0.01, respectively). TP53 mutation was associated with poor time to treatment failure and OS with the oxaliplatin-based regimen for first-line chemotherapy. Conclusions This study suggested that the genetic mutations influenced the prognosis and chemotherapy efficacy in AC.

Large-scale population cohort studies that collect genomic information are tasked with returning an assessment of genetic risk for hereditary cancers to participants. While several studies have applied to return identified genetic risks to participants, comprehensive surveys of participants’ understanding, feelings, and behaviors toward cancer risk remain to be conducted. Here, we report our experience and surveys of returning genetic risks to 100 carriers of pathogenic variants for hereditary cancers identified through whole genome sequencing of 50 000 individuals from the Tohoku Medical Megabank project, a population cohort study. The participants were carriers of pathogenic variants associated with either hereditary breast and ovarian cancer (n = 79, median age=41) or Lynch syndrome (n = 21, median age=62). Of these, 28% and 38% had a history of cancer, respectively. We provided information on cancer risk, heritability, and clinical actionability to the participants in person. The comprehension assessment revealed that the information was better understood by younger (under 60 years) females than by older males. Scores on the cancer worry scale were positively related to cancer experiences and general psychological distress. Seventy-one participants were followed up at Tohoku University Hospital; six females underwent risk-reducing surgery triggered by study participation and three were newly diagnosed with cancer during surveillance. Among first-degree relatives of hereditary breast and ovarian cancer carriers, participants most commonly shared the information with daughters. This study showed the benefits of returning genetic risks to the general population and will provide insights into returning genetic risks to asymptomatic pathogenic variant carriers in both clinical and research settings.

Pembrolizumab plus chemotherapy is considered one of the standard treatment regimens for patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC). The regimen comprises up to 6 cycles of pembrolizumab-chemotherapy combination phase and subsequent pembrolizumab maintenance phase. Pembrolizumab-chemotherapy combination confers high response rate, creating favorable conditions for pembrolizumab maintenance phase. This study examined the influence of response in the combination phase on the efficacy in subsequent maintenance phase. We retrospectively reviewed the medical records of patients with R/M HNSCC who received pembrolizumab plus chemotherapy as a first-line regimen at Tohoku University Hospital, Sendai, Japan. Progression-free survival (PFS) was analyzed when it was divided into the combination and maintenance phases. A total of 44 patients were enrolled. The best overall response was observed in the combination phase in all patients, and the overall response rate was 46.3

BACKGROUND:Germline mutations in BRCA1/2 are known to cause hereditary tumors in the breast, ovary, and other organs. With the widespread adoption of comprehensive diagnostics, including comprehensive genomic profiling (CGP) tests for solid tumors, many patients with BRCA1/2 variants have been identified. METHODS:In this study, we extracted and analyzed cases of BRCA1/2 variants that were presumed to be germline, which were repeatedly detected using the CGP test for solid tumors in northeastern Japan. The frequencies of BRCA1/2 variants in regional areas were compared with those of healthy individuals or nationwide cancer cohorts to investigate regional distribution. RESULTS:Our findings revealed regional disparities in BRCA1/2 pathogenic germline variants, while variants of unknown significance (VUS) showed no such differences. The regional distribution of BRCA1 and BRCA2 variants showed distinct patterns: pathogenic variants of BRCA1 exhibited regional differences and were less prevalent compared to VUS, whereas BRCA2 variants, including both pathogenic variants and VUS, did not exhibit such clear regional localization. This discrepancy in regional distribution between BRCA1 and BRCA2 variants could be attributed to factors such as the diversity of the genome, gender differences, and cancer types. CONCLUSIONS:These results highlight the importance of considering regional differences in comparative cohort studies, particularly in assessing the differential extension of mutations in pathogenic changes and VUS. Moreover, a presumption of pathogenicity variants would need to be discussed at the regional level.

Chemotherapy options for patients with advanced esophageal cancer had been limited until immune checkpoint inhibitors (ICIs) were approved for this indication. In recent years, ICI alone and ICI-combined chemotherapy have been approved, which prolonged the overall survival (OS) of patients with advanced esophageal cancer. We retrospectively analyzed 265 patients with unresectable advanced, recurrent, or metastatic esophageal squamous cell carcinoma (ESCC) who received chemotherapy with and without ICIs at Tohoku University Hospital from January 2013 to March 2022. Cisplatin plus fluorouracil therapy was the most frequently administered regimen as first-line treatment, and their administration frequency did not significantly differ between before 2019 and after 2020. Nivolumab was the most frequently used treatment as second-line therapy since its first approval in 2020 (74%), whereas taxanes were the most frequently used regimen before 2019 (55%). The median OS was 13.9 months over the entire observation period. Among patients who received second-line therapy, those receiving ICIs at any line demonstrated significantly longer OS from the start of second-line treatment than the others (p = 0.03). Univariate analysis revealed that a G8 score of < 11 (hazard ratio: 1.62, p = 0.02) was a prognostic factor in patients aged ≥ 65 years. Among each components of the G8 score, a decrease in food intake, weight loss, impaired mobility, and self-perceived poor health status were shown to be particularly associated with shorter OS. Our real-world data demonstrated that ICI administration contributed to improved OS after initiating second-line treatment for unresectable, advanced, or recurrent ESCC. Additionally, we revealed that the G8 score could be a useful prognostic factor in elderly patients with advanced ESCC treated with chemotherapy.