BACKGROUND AND AIMS:Oncogenic KRAS mutations are present in approximately 90% of pancreatic ductal adenocarcinoma (PDAC). However, Kras mutation alone is insufficient to transform precancerous cells into metastatic PDAC. This study investigates how KRAS-mutated epithelial cells acquire the capacity to escape senescence or even immune clearance, thereby progressing to advanced PDAC. METHODS:Single-cell RNA sequencing and analysis of primary PDAC tumors were conducted. Genetically engineered pancreas-specific Kras-mutated, dual specificity phosphatase-2 (Dusp2) knockout mouse models were established. Human and mouse primary pancreatic cancer cell lines were used for in vitro assessment of cancer characteristics. Tumor progression was studied via pancreas orthotopic and portal vein injection in the immune-competent mice. Clinical relevance was validated by digital spatial transcriptomic analysis of PDAC tumors. RESULTS:Kras mutation induces the formation of pancreatic intraepithelial neoplasia (PanIN), these lesions also exhibit significant apoptotic signals. Single-cell RNA sequencing identified a subset of ERKactiveDUSP2low cells continuing to expand from early to advanced stage PDAC. In vitro and in vivo studies reveal that early infiltrating macrophage-derived tissue inhibitor of metallopeptidase 1 (TIMP-1) is the key factor in maintaining the ERKactiveDUSP2low cell population in a CD63-dependent manner. The ERKactiveDUSP2low cancer cells further exacerbate macrophage-mediated cancer malignancy, including loss of epithelial trait, increased lymphangiogenesis, and immune escape. Digital spatial profiling analysis of PDAC samples demonstrates the colocalization of TIMP-1high macrophages and CD63high cancer cells. The presence of TIMP-1high macrophages and CD63high epithelial cells correlates with poor prognosis in PDAC. CONCLUSIONS:Our study reveals the vicious cycle between early infiltrating macrophages and pancreatic cancer cells, providing a mechanistic insight into the dynamic regulation directing pancreatic cancer progression.

633 Background: Immune checkpoint inhibitors (ICI) administered prior to liver resection (LR) lead to pathological responses in patients with hepatocellular carcinoma (HCC). However, the relative value of pathological versus radiological response in predicting relapse-free survival (RFS) remains unclear. Methods: We pooled patient-level data from 111 patients (pts) with HCC receiving ICI prior to LR as part of 5 phase I/II trials and observational clinical studies conducted in 12 centres in the United States, United Kingdom and Asia, as part of an academic consortium (NeoHCC). Pathological response was measured as the percentage of non-viable tumour in the resected specimen, with major (pMR) and complete pathological response (pCR) corresponding to ≥70% and 100% tumour regression. Radiological overall response rate (ORR) was assessed by RECIST v1.1 and modified RECIST (mRECIST) criteria. We correlated pathological response and ORR with RFS using Cox regression. Results: Pts received preoperative ICI between Oct 5, 2017, and Nov 15, 2023, mostly ICI combinations (69%, n=76). Most pts were male (78%, n=87) with viral chronic liver disease (66%, n=73), BCLC stage A HCC (55%, n=61). ORR was 28% per RECIST v1.1 and 32% per mRECIST criteria (available for n=81). Out of the 104 pathologically evaluable pts, pMR and pCR rates were 32% (n=33) and 18% (n=19). Radiological response by RECIST v1.1 showed a significant correlation with pathological response (R 2 = 0.43, p<0.001). When using RECIST v1.1, 74% of pts with ORR achieved pMR vs 14% of those without ORR (n=23/31 vs 10/73, p<0.001). However, 30% of pMR were not predicted by ORR (n=10/33). The discrepancy between pMR and ORR decreased using mRECIST. ORR per mRECIST was 83% in pMR pts (n=19/23), whereas it was 10% in non-pMR (n=5/51). After a median follow-up of 27.2 mos (95%CI 22.3-32.1), median RFS for the whole cohort was 43.6 mos (95%CI 28.3-NE). Achievement of pMR, pCR and ORR was associated with improved RFS (Table). However, reduction in the risk of relapse and/or death was higher in pts achieving pMR or pCR than ORR, regardless of the use of RECIST v1.1 or mRECIST. Conversely, pts without pMR had a lower mRFS than pts without ORR (28.3 mos [95%CI 12.8-43.8] and 32.8 mos [95%CI 13.7-51.9], respectively). Conclusions: Whilst radiological responses to neoadjuvant ICI are associated with improved RFS in pts with HCC, achievement of pMR is more accurate than RECIST and mRECIST-based responses in predicting for RFS, with lack of pMR identifying pts at a higher risk of relapse or mortality. Cox regression for RFS HR (95% CI) p value pCR 0.19 (0.05-0.78) 0.02 pMR 0.25 (0.10-0.66) 0.005 RECIST 1.1 0.34 (0.13-0.86) 0.02 mRECIST 0.38 (0.13-1.11) 0.08 RFS, relapse-free survival; HR, hazard ratio; CI, confidence interval; pCR, complete pathological response; pMR, major pathological response; mRECIST, modified RECIST.

Background Neoadjuvant use of immune checkpoint inhibitors (ICIs) before liver resection results in pathological tumour regression in patients with hepatocellular carcinoma. We aimed to describe the characteristics of pathological responses after preoperative ICI therapy for hepatocellular carcinoma and to evaluate the association between the depth of tumour regression and relapse-free survival. Methods In this cross-trial, patient-level analysis, we performed a pooled analysis ofdata from patients with hepatocellular carcinoma receiving ICI therapy before liver resection as part of a global collaborative consortium (NeoHCC) of five phase 1 and 2 clinical trials and standardised observational protocols conducted in 12 tertiary referral centres across the USA, UK, and Taiwan. Eligible patients were adults (aged >= 18 years) diagnosed with hepatocellular carcinoma by tissue core biopsy before treatment initiation, a Liver Imaging Reporting and Data System score of 5 on imaging, or both, with an Eastern Cooperative Oncology Group performance status score of 0-1, and no extrahepatic spread or previous ICI treatment. Pathological response was measured as the percentage of non-viable tumour in the resected surgical specimen, with major pathological response corresponding to at least 70% tumour regression and pathological complete response corresponding to 100% tumour regression. We correlated pathological response with radiological overall response using RECIST criteria (version 1.1) and relapse-free survival, and evaluated the threshold of tumour regression that could be optimally associated with relapse-free survival. Findings At data cutoff on Jan 31, 2024, 111 patients were included in the study, of whom data on pathological response were available for 104 (94%) patients. Patients received treatment from Oct 5, 2017, to Nov 15, 2023, mostly ICI combinations (76 [69%]), for a median of 14 months (IQR 07-29). 87 (78%) patients were men and 24 (22%) were women. Most patients had underlying viral chronic liver disease (73 [66%]) and Barcelona Clinic Liver Cancer stage A hepatocellular carcinoma (61 [55%]), without portal vein thrombosis (87 [78%]). We observed major pathological response in 33 (32%) patients and pathological complete response in 19 (18%) patients. Radiological overall response was associated with major pathological response, with 23 (74%) of 31 patients with radiological response showing major pathological response compared with ten (14%) of 73 patients without radiological response (p<00001). However, ten (30%) of 33 major pathological responses were not predicted by radiological response. After a median follow-up of 272 months (95% CI 223-321), median relapse-free survival for the whole cohort was 436 months (95% CI 283- not evaluable). Relapse-free survival was significantly longer in patients with major pathological response than in those who did not have a major pathological response (not reached [95% CI not evaluable-not evaluable] vs 283 months [128-438]; hazard ratio 026 [010-066]; p=00024) and in patients with pathological complete response than in those who did not have a pathological complete response (NR [95% CI not evaluable-not evaluable] vs 328 months [150-505]; 019 [005-078]; p=0010). Unbiased recursive partitioning of the cohort for the risk of relapse, death, or both identified a threshold of 90% as the optimal cutoff of pathological tumour regression to predict improved relapse-free survival. Interpretation The extent of tumour regression following neoadjuvant ICI therapy could identify patients with improved relapse-free survival following liver resection. The threshold of at least 90% tumour regression should be validated for its surrogate role for relapse-free survival in phase 3 randomised controlled trials.

Background/objectives: Liposomal irinotecan plus 5-fluorouracil and leucovorin (nal-IRI + 5-FU/LV) provides survival benefits for metastatic pancreatic adenocarcinoma (mPDAC) refractory to gemcitabinebased treatment, mainly gemcitabine plus nab-paclitaxel (GA), in current practice. Gemcitabine plus S-1 (GS) is another commonly administered first -line regimen before nab-paclitaxel reimbursement; however, the efficacy and safety of nal-IRI + 5-FU/LV for mPDAC after failed GS treatment has not been reported and was therefore explored in this study. Methods: In total, 177 patients with mPDAC received first -line GS or GA treatment, followed by secondline nal-IRI + 5-FU/LV treatment (identified from a multicenter retrospective cohort in Taiwan from 2018 to 2020); 85 and 92 patients were allocated to the GS and GA groups, respectively. Overall survival (OS), time-to-treatment failure (TTF), and adverse events were compared between the two groups. Results: The baseline characteristics of the two groups were generally similar; however, a higher median age (67 versus 62 years, p < 0.001) and fewer liver metastases (52% versus 78%, p < 0.001) were observed in the GS versus GA group. The median OS was 15.0 and 15.9 months in the GS and GA groups, respectively (p = 0.58). The TTF (3.1 versus 2.8 months, p = 0.36) and OS (7.6 versus 6.7 months, p = 0.83) after nal-IRI treatment were similar between the two groups. More patients in the GS group developed mucositis during nal-IRI treatment (15% versus 4%, p = 0.02). Conclusions: The efficacy of second -line nal-IRI +5-FU/LV treatment was unaffected by prior S-1 exposure. GS followed by nal-IRI treatment is an alternative treatment sequence for patients with mPDAC. (c) 2024 IAP and EPC. Published by Elsevier B.V. All rights reserved.

Burkitt lymphoma is characterized by high cell turnover and numerous cytoplasmic vacuoles that are demonstrated to be lipid droplets (LDs) decorated by adipophilin. By contrast, cytoplasmic vacuoles are variably observed in diffuse large B-cell lymphoma (DLBCL) and less well characterized. In this study, we first validated in DLBCL that cytoplasmic vacuoles are indeed LDs by Oil-red-O stain, Bodipy fluorescent stain, and electron microscopy. Second, in a cohort of DLBCL patients (n=52) we showed that LDs in effusional lymphoma cells were associated with a poorer prognosis (P=0.029, log-rank test) and higher International Prognostic Index (IPI) score (94% vs. 66%, P=0.026) than those without. Moreover, using adipophilin as a surrogate marker for LDs, we found in another cohort of biopsy specimen (n=85) that expression of adipophilin by lymphoma cells predicted a poorer prognosis (P=0.007, log-rank test) and higher IPI score (63% vs. 30%, P=0.005). In addition, whole exome sequencing of effusional DLBCL cells showed LD-positive DLBCL shared genetic features with the MCD (MYD88 and CD79B mutations) subtype and highlighted OSBPL10 and CUBN as the most frequently mutated genes involved in lipogenesis. Whole transcriptome analysis by comparing effusional DLBCL cells with versus without LDs showed upregulation of EHHADH, SLC1A1, CD96, INPP4B, and RNF183 relevant for lymphoma lipogenesis and upregulation of epithelial-mesenchymal transition and KRAS signaling pathways. Higher expression of EHHADH and CD96 were validated in LD-positive clinical samples and LD-rich cell lines than LD-poor cells along with the known lipogenic gene, FASN. Our findings highlight the roles of LDs and adipophilin expression in DLBCL, suggest that these markers may predict prognosis and show that lipogenic genes may be potential therapeutic targets.

Burkitt lymphoma is characterized by high cell turnover and numerous cytoplasmic vacuoles that are demonstrated to be lipid droplets (LDs) decorated by adipophilin. By contrast, cytoplasmic vacuoles are variably observed in diffuse large B-cell lymphoma (DLBCL) and less well characterized. In this study, we first validated in DLBCL that cytoplasmic vacuoles are indeed LDs by Oil-red-O stain, Bodipy fluorescent stain, and electron microscopy. Second, in a cohort of DLBCL patients (n=52) we showed that LDs in effusional lymphoma cells were associated with a poorer prognosis ( P =0.029, log-rank test) and higher International Prognostic Index (IPI) score (94% vs. 66%, P =0.026) than those without. Moreover, using adipophilin as a surrogate marker for LDs, we found in another cohort of biopsy specimen (n=85) that expression of adipophilin by lymphoma cells predicted a poorer prognosis ( P =0.007, log-rank test) and higher IPI score (63% vs. 30%, P =0.005). In addition, whole exome sequencing of effusional DLBCL cells showed LD-positive DLBCL shared genetic features with the MCD ( MYD88 and CD79B mutations) subtype and highlighted OSBPL10 and CUBN as the most frequently mutated genes involved in lipogenesis. Whole transcriptome analysis by comparing effusional DLBCL cells with versus without LDs showed upregulation of EHHADH , SLC1A1 , CD96 , INPP4B , and RNF183 relevant for lymphoma lipogenesis and upregulation of epithelial-mesenchymal transition and KRAS signaling pathways. Higher expression of EHHADH and CD96 were validated in LD-positive clinical samples and LD-rich cell lines than LD-poor cells along with the known lipogenic gene, FASN . Our findings highlight the roles of LDs and adipophilin expression in DLBCL, suggest that these markers may predict prognosis and show that lipogenic genes may be potential therapeutic targets.

BACKGROUND:Oxaliplatin- and fluoropyrimidine-based triplet regimens have demonstrated feasibility and efficacy in the treatment of upper gastrointestinal (UGI) cancers. Herein, we evaluate the feasibility and preliminary efficacy of biweekly nab-paclitaxel plus oxaliplatin and S-1/leucovorin (SOLAR) in chemonaïve UGI cancers. METHODS:A 3 + 3 phase 1 study was conducted to determine the maximal tolerated dose (MTD) of oxaliplatin in SOLAR (nab-paclitaxel [150 mg/m2 in D1], oxaliplatin [60, 75, or 85 mg/m2 in D1], and oral S-1/leucovorin [35 mg/m2 and 30 mg bid from D1 to D7]). The secondary endpoints were overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety. RESULTS:Thirteen and 6 accruals were in the dose-escalation and MTD expansion cohorts, respectively. One of 6 patients at level III experienced dose-limiting toxicity (grade 3 diarrhea), which revealed that the MTD of oxaliplatin was 85 mg/m2. After a mean of 15.9 cycles of treatment, the most common treatment-related grade 3/4 toxicities were neutropenia (57.9%) and diarrhea (21.1%). The ORR was 63.2%. The median PFS and OS were 12.5 and 24.7 months, respectively. CONCLUSION:The current study revealed the MTD of oxaliplatin and demonstrated the preliminary efficacy of SOLAR in UGI cancers, which deserves further investigation. CLINICALTRIALS.GOV IDENTIFIER:NCT03162510.

Introduction The progression patterns, dispositions, and outcomes of patients with advanced hepatocellular carcinoma (HCC) who achieved durable responses with immunotherapy remain poorly characterized. Methods Patients with advanced HCC who received immune checkpoint inhibitor (ICI)-based immunotherapy and achieved durable responses were retrospectively included. A durable response was defined as partial response (PR) or stable disease (SD) per RECIST 1.1 for more than 8 months after initiation of immunotherapy. Oligoprogression and polyprogression were defined as progression at ≤ 3 and > 3 lesions, respectively. Results A total of 91 durable responders (63 PR and 28 SD) were identified. The majority had chronic viral hepatitis (n=69, 75.8%). Forty-seven (51.6%) and 44 (48.4%) patients received the index immunotherapy as first-line and second or beyond-line therapy, respectively. Fifty-four (59.3%) patients subsequently developed progression, with a predominant pattern of oligoprogression (66.7%). The median overall survival (OS) was 46.2 months (95% CI: 34.1–58.3). For patients with subsequent progression, employment of locoregional therapy (LRT) for progression was associated with prolonged OS (univariate analysis: hazard ratio [HR] 0.397, p=0.009; multivariate analysis: HR 0.363, p=0.050). Patients with oligoprogression who received LRT showed longer median OS than those who did not (48.4 vs. 20.5 months, p<0.001). In contrast, the median OS of patients with polyprogression who received LRT was not different from those without LRT (27.7 vs. 25.5 months, p=0.794). Conclusion Approximately 60% of the post-immunotherapy durable responders of HCC subsequently develop progression. Proactive LRT may further rescue patients who develop subsequent oligoprogression. Prospective studies are mandatory to clarify the proper management of durable responders with subsequent progression.

PURPOSE Durable partial response (PR) and durable stable disease (SD) are often seen in patients with hepatocellular carcinoma (HCC) receiving atezolizumab plus bevacizumab (atezo-bev). This study investigates the outcome of these patients and the histopathology of the residual tumors. PATIENTS AND METHODS The IMbrave150 study's atezo-bev group was analyzed. PR or SD per RECIST v1.1 lasting more than 6 months was defined as durable. For histologic analysis, a comparable real-world group of patients from Japan and Taiwan who had undergone resection of residual tumors after atezo-bev was investigated. RESULTS In the IMbrave150 study, 56 (77.8%) of the 72 PRs and 41 (28.5%) of the 144 SDs were considered durable. The median overall survival was not estimable for patients with durable PR and 23.7 months for those with durable SD. The median progression-free survival was 23.2 months for patients with durable PR and 13.2 months for those with durable SD. In the real-world setting, a total of 38 tumors were resected from 32 patients (23 PRs and nine SDs) receiving atezo-bev. Pathologic complete responses (PCRs) were more frequent in PR tumors than SD tumors (57.7% v 16.7%, P = .034). PCR rate correlated with time from atezo-bev initiation to resection and was 55.6% (5 of 9) for PR tumors resected beyond 8 months after starting atezo-bev, a time practically corresponding to the durable PR definition used for IMbrave150. We found no reliable radiologic features to predict PCR of the residual tumors. CONCLUSION Durable PR patients from the atezo-bev group showed a favorable outcome, which may be partly explained by the high rate of PCR lesions. Early recognition of PCR lesions may help subsequent treatment decision.

Background Cancer susceptibility germline mutations are associated with pancreatic ductal adenocarcinoma (PDAC). However, the hereditary status of PDAC and its impact on survival is largely unknown in the Asian population. Methods Exome sequencing was performed on 527 blood samples from PDAC individuals and analyzed for mutations in 80 oncogenic genes. Pathogenic and likely pathogenic (P/LP) germline variants were diagnosed according to the ACMG variant classification categories. The association between germline homologous recombination gene mutations ( gHR mut , including BAP1 , BRCA1 , BRCA2 , PALB2 , ATM , BLM , BRIP1 , CHEK2 , NBN , MUTYH , FANCA and FANCC ) and the treatment outcomes was explored in patients with stage III/IV diseases treated with first-line (1L) platinum-based versus platinum-free chemotherapy. Results Overall, 104 of 527 (19.7%) patients carried germline P/LP variants. The most common mutated genes were BRCA2 (3.60%), followed by ATR (2.66%) and ATM (1.9%). After a median follow-up duration of 38.3-months (95% confidence interval, 95% CI 35.0–43.7), the median overall survival (OS) was not significantly different among patients with gHR mut , non- HR germline mutations, or no mutation ( P = 0.43). Among the 320 patients with stage III/IV disease who received 1L combination chemotherapy, 32 (10%) had gHR mut . Of them, patients receiving 1L platinum-based chemotherapy exhibited a significantly longer median OS compared to those with platinum-free chemotherapy, 26.1 months (95% CI 12.7–33.7) versus 9.6 months (95% CI 5.9–17.6), P = 0.001. However, the median OS of patients without gHR mut was 14.5 months (95% CI 13.2–16.9) and 12.6 months (95% CI 10.8–14.7) for patients receiving 1L platinum-based and platinum-free chemotherapy, respectively ( P = 0.22). These results were consistent after adjusting for potential confounding factors including age, tumor stage, performance status, and baseline CA 19.9 in the multivariate Cox regression analysis. Conclusions Our study showed that nearly 20% of Taiwanese PDAC patients carried germline P/LP variants. The longer survival observed in gHR mut patients treated with 1L platinum-based chemotherapy highlights the importance of germline testing for all patients with advanced PDAC at diagnosis.

Perineural invasion and neurogenesis are frequently observed in pancreatic ductal adenocarcinoma (PDAC) and link to poor outcome. However, how neural factors affect PDAC prognosis and the underlying mechanism as well as counteracting therapeutic are still unclear. In silico systematic analysis was performed with PROGgene to identify potential neural factor and its receptor in pancreatic cancer. In vitro assays including migration, invasion, 3D recruitment, and gemcitabine resistance were performed to study the effect of neuron-derived neurotensin (NTS) on pancreatic cancer behavior. Orthotopic animal study was used to validate the in vitro findings. Gene set enrichment analysis (GSEA) was performed to confirm the results from in silico to in vivo. Expression of NTS and its receptor 1 (NTSR1) predicted poor prognosis in PDAC. NTS synthetic peptide or neuron-derived condition medium promoted pancreatic cancer invasiveness and recruitment in 2D and 3D assays. NTS-induced effects depended on NTSR1 and PI3K activation. GDC-0941, a clinically approved PI3K inhibitor, counteracted NTS-induced effects in vitro. Inhibition of NTSR1 in pancreatic cancer cells resulted in decreased tumor dissemination and diminished PI3K activation in vivo. NTS boosted gemcitabine resistance via NTSR1 in pancreatic cancer. Our results suggest that neural cell-secreted NTS plays an important role in promoting PDAC.

506 Background: Neoadjuvant use of immune checkpoint inhibitors (ICI) is feasible and achieves pathological responses in a subset of patients with hepatocellular carcinoma (HCC). However, it is not clear whether pathological response to ICI translates into long-term survival benefit. Methods: We analysed patient-level data from 86 subjects recruited to 4 prospective phase I/II clinical trials of ICI prior to liver resection (LR) in 9 centres in the United States, Europe, and Asia and included a cohort of 23 patients (pts) receiving neoadjuvant ICI off trial. Radiological response was assessed with RECISTv1.1. Major (MPR) and complete pathological response (pCR) were considered as ≥70% and 100% non-viable tumour in the resected specimen, respectively. Pathological responses were correlated with radiologic overall response rates (ORR) and relapse-free survival (RFS). Results: Out of 109 pts treated between 10/2017 and 09/2023, 55 pts (50.5%) received a double ICI combination, 35 (32.1%) ICI monotherapy, and 19 (17.4%) an antiangiogenic/ICI combination. In 19 pts (17.4%) an adjuvant ICI course was administered for a median time of 5.5 months (m) (interquartile range [IQR] 3.7-6.0). Most of pts were male (77.6%) with underlying viral chronic liver disease (68.2%), performance status 0 (83.5%), BCLC 0-A (55%), a median tumour diameter of 6.0 cm (IQR 3.9-9.9) without portal vein thrombosis (75.7%). After a median follow-up of 27.3 m (95% CI 21.5-33.0), 35 (32.1%) relapses and 14 (12.8%) deaths occurred. Radiologic ORR was 28.5% (n=31), with 3.7% complete responses (CR, n=4) and 24.8% partial responses (PR, n=27). Out of 100 pts evaluable for a pathological response, 33% achieved MPR and 19% pCR. MPR was more likely in patients who had achieved a radiologic PR or CR (82%) as compared to those who did not (14% p<0.001), however linear correlation suggested an imperfect correlation between ORR and MPR (R 2 0.43, p<0.0001). Median RFS was 43.5m (95%CI, 27.5-59.6), while median overall survival was not reached (NR). mRFS was significantly improved in pts with MPR (NR vs 28.3m [95%CI, 13.1-43.5], hazard ratio [HR] 0.27 [95%CI, 0.11-0.69], p = 0.003) and with pCR (NR vs 32.8m [95%CI, 15.2-50.4], HR 0.20 [95%CI, 0.05-0.82], p=0.013). Conclusions: This study is the first to qualify the role of MPR as a putative surrogate endpoint for recurrence-free survival in pts treated with neoadjuvant immunotherapy for HCC. Validation in larger phase III clinical trials is warranted.

Background and Aims: The red material occupying the larger portion of the acquired sample in EUS fine-needle biopsy (FNB) is seldom investigated. We aimed to evaluate the composition of the red material. Methods: Patients with a solid pancreatic mass who received EUS FNB from September 2020 to June 2021 were enrolled. The white or yellowish content with apparent bulk (white material) and the rest of pasta-like red content (red material) were separated immediately after puncture. Needle passes proceeded until 2 specimens with >4 mm of white material were obtained. An extra needle pass was conducted for DNA collection. The DNA amount, Kirsten rat sarcoma virus (K-ras) mutation type, and mutation allele frequency were compared between the white and red material. Results: Forty patients were enrolled with 68 paired white and red materials. The diagnostic accuracy was slightly higher in the white material (92.5% vs 82.5%, P = .219). On the histology slides, the area of the tumor gland was comparable in both materials, but the total tissue area was larger in the red material (9.74 mm(2) and 10.74 mm(2) larger according to generalized linear model and generalized estimating equation, respectively; both, P < .001). The amount of DNA was significantly higher in the red material (2.99 [interquartile range, 1.59-7.29] mu g vs .70 [interquartile range, .27-1.24] mu g; P < .001). Common pancreatic adenocarcinoma K-ras mutation was identified at a rate of 85% for the white material and 95% for the red material. Regardless of whether red or white material was used, there was a high concordance of K-ras mutation types (34 of 40 [85%]) and a high correlation of mutation allele frequency (rho = .66, P < .001). Conclusions: In EUS FNB, the red material contains a higher amount of tumor DNA and can be an alternative source for tumor DNA analysis.

Supplementary Figure from Impaired Chromatin Remodeling Predicts Better Survival to Modified Gemcitabine and S-1 plus Nivolumab in Advanced Biliary Tract Cancer: A Phase II T1219 Study

11551 Background: Liver AS has a grave prognosis and our previous study (Chen TW et al. Cancer 2022) showed that the incidence of liver AS is higher in Asia. We aimed to investigate the etiology of liver AS and its molecular characteristics. Methods: We performed whole exome (WES) and transcriptome sequencing (RNA-seq) of AS (liver 10, scalp 5, breast 2, trunk 1, heart 1) and hepatocellular carcinoma (HCC, 9) from National Taiwan University Hospital (NTUH) and re-analyzed WES & RNA-seq of AS from the Count Me In Project (CMI, 46). Somatic mutations and copy number alternation were called by Mutect2 and Sequenza from tumor-normal matched WES. Non-negative matrix factorization was used to determine mutational signature profiles and the contributions of each signature to each sample. Telomere length was estimated using TelSeq. Results: We identified four single-base-substitution (SBS) signatures using somatic mutations from 74 (AS/HCC 65/9) WES data. The dominated signature in liver AS had exceptionally high cosine similarity (93.08%) with COSMIC SBS22 (ver 3.2), which is related to AA exposure. The AA-mutation signature contributed significantly (adjusted p < 0.01) to the DNA mutations in 70% (7/10), 0% (0/9), 7% (3/46), and 56% (5/9) of liver AS (NTUH), nonliver AS (NTUH), CMI AS, and HCC (NTUH), respectively. TP53 (60% vs 22% vs 32%) and ATRX (40% vs 0% vs 11%) mutations were more common in liver than nonliver AS (NTUH) or CMI, while KDR mutation rates were similar (30% vs 44% vs 22%). Among TP53 mutations from liver AS with AA signature, 86% (6/7) showed the typical A:T > T:A mutation caused explicitly by AA-induced DNA damage. In liver vs nonliver AS, the median number of mutations and neoantigen burdens were 6.55 vs 0.98 (p = 0.0076) and 1572 vs 544 (p = 0.095), respectively. Although liver AS and HCC were highly associated with AA-mutation signature, liver AS had significantly longer telomeres in terms of tumor/normal telomere ratio (median 1.27 vs 1.16, p = 0.0009) but a significantly lower telomerase enzyme activity (p = 0.016). We did not find an association between ATRX mutation, or its mRNA expression level, with the extended telomere length in liver AS. Compared to nonliver AS, the activity of the telomere replication molecule BUB1 was significantly higher in liver AS (p = 0.0029). Conclusions: Our study is the first to connect AA exposure to the etiology of liver AS. The high mutation rate and distinct telomere maintenance mechanism of liver AS provides insights into future treatments.

Perineural invasion and neurogenesis are frequently observed in pancreatic ductal adenocarcinoma (PDAC), and they are associated with a poor prognosis. Axon guidance factor semaphorin 3A (SEMA3A) is upregulated in PDAC. However, it remains unclear whether cancer-derived SEMA3A influences nerve innervation and pancreatic tumorigenesis. In silico analyses were performed using PROGgene and NetworkAnalyst to clarify the importance of SEMA3A and its receptors, plexin A1 (PLXNA1) and neuropilin 2 (NRP2), in pancreatic cancer. In vitro assays, including migration, neurite outgrowth, and 3D recruitment, were performed to study the effects of SEMA3A on neuronal behaviors. Additionally, an orthotopic animal study using C57BL/6 mice was performed to validate the in vitro findings. Expression of SEMA3A and its receptors predicted worse prognosis for PDAC. Cancer-derived SEMA3A promoted neural migration, neurite outgrowth, and neural recruitment. Furthermore, SEMA3A-induced effects depended on PLXNA1, NRP2, and MAPK activation. Trametinib, an approved MAPK kinase (MEK) inhibitor, counteracted SEMA3A-enhanced neuronal activity in vitro. Inhibition of SEMA3A by shRNA in pancreatic cancer cells resulted in decreased neural recruitment, tumor growth, and dissemination in vivo. Our results suggested that cancer-secreted SEMA3A plays an important role in promoting neo-neurogenesis and progression of PDAC.

Pancreatic cancer is a highly aggressive malignancy with a poor prognosis. Over the past decade, significant therapeutic advancements have improved the survival rates of patients with pancreatic cancer. One of the primary factors contributing to these positive outcomes is the evolution of chemotherapy, from monotherapy to doublet or triplet regimens, and the integration of multimodal approaches. Additionally, targeted agents tailored to patients with specific genetic alterations and the development of cell therapies show promise in benefiting certain subpopulations. This article focuses on examining pivotal studies that explore the role of chemotherapy in neoadjuvant, adjuvant, maintenance, and salvage settings; highlights interesting findings related to cell therapy; and provides an overview of ongoing trials concerning metastatic settings. This review primarily aimed to offer recommendations based on therapeutic evidence, recent advancements in new treatment combinations, and the most innovative approaches. A unique aspect of this review is the inclusion of published papers on clinical trials and real-world data in Taiwan, thus adding a valuable perspective to the overall analysis.

This study evaluated the efficacy, safety, and surgical outcome for HCC patients who are potentially eligible for curative surgery after neoadjuvant N+I, as defined by one of the following: (a) macrovascular invasion (AJCC T3) (b) multiple (>3) or tumors in bilateral lobes (AJCC T2) (c) AJCC T2 tumors with significant portal hypertension (d) other conditions with high risk of recurrence (NCT03510871).

Background/Aims: A high-quality sample allows for next-generation sequencing and the administration of more tailored precision medicine treatments. We aimed to evaluate whether heparinized wet suction can obtain higher quality samples than the standard dry-suction method during endoscopic ultrasound (EUS)-guided biopsy of pancreatic masses.Methods: A prospective randomized crossover study was conducted. Patients with a solid pancreatic mass were randomly allocated to receive either heparinized wet suction first or dry suction first. For each method, two needle passes were made, followed by a switch to the other method for a total of four needle punctures. The primary outcome was the aggregated white tissue length. Histological blood contamination, diagnostic performance and adverse events were analyzed as secondary outcomes. In addition, the correlation between white tissue length and the extracted DNA amount was analyzed.Results: A total of 50 patients were enrolled, and 200 specimens were acquired (100 with heparinized wet suction and 100 with dry suction), with one minor bleeding event. The heparinized wet suction approach yielded specimens with longer aggregated white tissue length (11.07 mm vs 7.96 mm, p=0.001) and less blood contamination (p=0.008). A trend towards decreasing tissue quality was observed for the 2nd pass of the dry-suction method, leading to decreased diagnostic sensitivity and accuracy, although the accumulated diagnostic performance was comparable between the two suction methods. The amount of extracted DNA correlated positively to the white tissue length (p=0.001, Spearman̕s ρ=0.568).Conclusions: Heparinized wet suction for EUS tissue acquisition of solid pancreatic masses can yield longer, bloodless, DNA-rich tissue without increasing the incidence of adverse events (ClinicalTrials.gov. identifier NCT04707560).