Factors Affecting Nonfunctioning Small Pancreatic Neuroendocrine Neoplasms and Proposed New Treatment Strategies.

BACKGROUND & AIMS: Despite previously reported treatment strategies for nonfunctioning small (≤20 mm) pancreatic neuroendocrine neoplasms (pNENs), uncertainties persist. We aimed to evaluate the surgically resected cases of nonfunctioning small pNENs (NF-spNENs) in a large Japanese cohort to elucidate an optimal treatment strategy for NF-spNENs. METHODS: In this Japanese multicenter study, data were retrospectively collected from patients who underwent pancreatectomy between January 1996 and December 2019, were pathologically diagnosed with pNEN, and were treated according to the World Health Organization 2019 classification. Overall, 1490 patients met the eligibility criteria, and 1014 were included in the analysis cohort. RESULTS: In the analysis cohort, 606 patients (59.8%) had NF-spNENs, with 82% classified as grade 1 (NET-G1) and 18% as grade 2 (NET-G2) or higher. The incidence of lymph node metastasis (N1) by grade was significantly higher in NET-G2 (G1: 3.1% vs G2: 15.0%). Independent factors contributing to N1 were NET-G2 or higher and tumor diameter ≥15 mm. The predictive ability of tumor size for N1 was high. Independent factors contributing to recurrence included multiple lesions, NET-G2 or higher, tumor diameter ≥15 mm, and N1. However, the independent factor contributing to survival was tumor grade (NET-G2 or higher). The appropriate timing for surgical resection of NET-G1 and NET-G2 or higher was when tumors were >20 and >10 mm, respectively. For neoplasms with unknown preoperative grades, tumor size >15 mm was considered appropriate. CONCLUSIONS: NF-spNENs are heterogeneous with varying levels of malignancy. Therefore, treatment strategies based on tumor size alone can be unreliable; personalized treatment strategies that consider tumor grading are preferable.

Reconsideration of the clinical impact of neoadjuvant therapy in resectable and borderline resectable pancreatic cancer: A dual-institution collaborative clinical study.

PURPOSE: We investigated true indication of neoadjuvant therapy (NAT) in resectable pancreatic cancer and the optimal surgical timing in borderline resectable pancreatic cancer. METHODS: A total of 687 patients with resectable or borderline resectable pancreatic cancer were enrolled. Survival analysis was performed by intention-to-treat analysis and propensity score matching (PSM) was conducted. RESULTS: In resectable disease, the NAT group showed better overall survival (OS) compared with the upfront group. Multivariate analysis identified CA19-9 level (≥100 U/mL) and lymph node metastasis to be prognostic factors, and a tumor size of 25 mm was the optimal cut-off value to predict lymph node metastasis. There was no significant survival difference between patients with a tumor size ≤25 mm and CA19-9 < 100 U/mL and those in the NAT group. In borderline resectable disease, OS in the NAT group was significantly better than that in the upfront group. CEA (≥5 ng/mL) and CA19-9 (≥100 U/mL) were identified as prognostic factors; however, the OS of patients fulfilling these factors was worse than that of the NAT group. CONCLUSIONS: NAT could be unnecessary in patients with tumor size ≤25 mm and CA19-9 < 100 U/mL in resectable disease. In borderline resectable disease, surgery should be delayed until tumor marker levels are well controlled.

Impact of endoscopic ultrasound-guided tissue acquisition on prognosis and peritoneal lavage cytology in resectable or borderline resectable pancreatic ductal adenocarcinoma.

OBJECTIVES: This study aimed to evaluate the clinical impact of preoperative endoscopic ultrasound-guided tissue acquisition (EUS-TA) on the prognosis and incidence of positive peritoneal lavage cytology (PLC) during laparotomy or staging laparoscopy in patients with resectable (R) or borderline resectable (BR) pancreatic ductal adenocarcinoma (PDAC). METHODS: We retrospectively collected data from patients diagnosed with body and tail PDAC with/without EUS-TA at our hospital from January 2006 to December 2021. RESULTS: To examine the effect of EUS-TA on prognosis, 153 patients (122 in the EUS-TA group, 31 in the non-EUS-TA group) were analyzed. There was no significant difference in overall survival between the EUS-TA and non-EUS-TA groups after PDAC resection (P = 0.777). In univariate and multivariate analysis, preoperative EUS-TA was not identified as an independent factor related to overall survival after pancreatectomy [hazard ratio 0.96, 95 % confidence interval (CI) 0.54-1.70, P = 0.897]. Next, to examine the direct influence of EUS-TA on the results of PLC, 114 patients (83 in the EUS-TA group and 31 in the non-EUS-TA group) were analyzed. Preoperative EUS-TA was not statistically associated with positive PLC (odds ratio 0.73, 95 % CI 0.25-2.20, P = 0.583). After propensity score matching, overall survival and positive PLC were the same in both groups. CONCLUSIONS: EUS-TA had no negative impact on postoperative survival and PLC-positive rates in R/BR PDAC.

Survival impact of occult liver metastasis and peritoneal dissemination compared with radiologically defined distant organ metastasis in pancreatic ductal adenocarcinoma.

BACKGROUND: Characteristics and prognoses of patients with occult metastases (OM) of pancreatic ductal adenocarcinoma (PDAC) compared with radiologically defined metastases (RM) have been rarely reported. OBJECTIVE: We aimed to clarify the prognosis of OM compared with RM and to establish a treatment strategy for PDAC patients with OM. METHODS: This single-institution, retrospective study evaluated patients with unresectable PDAC between 2008 and 2018. OM was defined as abdominal metastasis that was detected by staging laparoscopy or open laparotomy but not in the initial assessment of radiological images. RESULTS: OM and RM were identified in 135 and 112 patients, respectively. Eastern Cooperative Oncology Group Performance Status (ECOG PS), neutrophil to lymphocyte ratio (NLR), tumor diameter, and rate of local unresectability were significantly lower in the OM group. Median overall survival (OS) of OM was significantly better than that of RM (13.0 vs 8.9 months, p < 0.001). In multivariate analysis of OS, ECOG PS ≥ 1 (HR 1.64, p = 0.009), NLR ≥5 (HR 1.97, p = 0.004), carbohydrate antigen (CA) 19-9 ≥1000 (HR 1.68, p = 0.001), tumor diameter ≥40 mm (HR 1.40, p = 0.027), conversion surgery (HR 0.12, p < 0.001), and multiple lines of chemotherapy (HR 0.38, p < 0.001) were independent predictors. However, type of metastasis (OM vs RM) not an independent predictor (HR 1.10, p = 0.590). CONCLUSION: The prognosis of PDAC with OM was relatively better than that with RM, but general and nutritional statuses, primary tumor size and CA19-9, conversion surgery and multiple lines of chemotherapy were independent predictors but not tumor burden.

Impact of neoadjuvant therapy on gut microbiome in patients with resectable/borderline resectable pancreatic ductal adenocarcinoma.

BACKGROUND: /Objectives: Effects of chemotherapy on gut microbiota have been reported in various carcinomas. The current study aimed to evaluate the changes in the gut microbiota before and after neoadjuvant chemotherapy (NAC) in patients with resectable (R) and borderline resectable (BR) pancreatic ductal adenocarcinoma (PDAC) and understand their clinical implications. METHODS: Twenty patients diagnosed with R/BR-PDAC were included in this study. Stool samples were collected at two points, before and after NAC, for microbiota analysis using 16S ribosomal RNA (16S rRNA) gene sequences. RESULTS: Of the 20 patients, 18 (90%) were treated with gemcitabine plus S-1 as NAC, and the remaining patients received gemcitabine plus nab-paclitaxel and a fluorouracil, leucovorin, irinotecan, and oxaliplatin combination. No significant differences were observed in the α- and ß-diversity before and after NAC. Bacterial diversity was not associated with Evans classification (histological grade of tumor destruction by NAC) or postoperative complications. The relative abundance of Actinobacteria phylum after NAC was significantly lower than that before NAC (P = 0.02). At the genus level, the relative abundance of Bifidobacterium before NAC in patients with Evans grade 2 disease was significantly higher than that in patients with Evans grade 1 disease (P = 0.03). Patients with Evans grade 2 lost significantly more Bifidobacterium than patients with Evans grade 1 (P = 0.01). CONCLUSIONS: The diversity of gut microbiota was neither decreased by NAC for R/BR-PDAC nor associated with postoperative complications. Lower incidence of Bifidobacterium genus before NAC may be associated with a lower pathological response to NAC.

Is surgical resection justified for pancreatic ductal adenocarcinoma with distant abdominal organ metastasis? A position paper by experts in pancreatic surgery at the Joint Meeting of the International Association of Pancreatology (IAP) & the Japan Pancreas Society (JPS) 2022 in Kyoto.

Pancreatic ductal adenocarcinoma (PDAC) is a typical refractory malignancy, and many patients have distant organ metastases at diagnosis, such as liver metastasis and peritoneal dissemination. The standard treatment for unresectable PDAC with distant organ metastasis (UR-M) is chemotherapy, but the prognosis remained poor. However, with recent dramatic developments in chemotherapy, the prognosis has gradually improved, and some patients have experienced marked shrinkage or disappearance of their metastatic lesions. With this trend, attempts have been made to resect a small number of metastases (so-called oligometastases) in combination with the primary tumor or to resect the primary and metastatic tumor in patients with a favorable response to anti-cancer treatment after a certain period of time (so-called conversion surgery). An international consensus meeting on surgical treatment for UR-M PDAC was held during the Joint Congress of the 26th Meeting of the International Association of Pancreatology (IAP) and the 53rd Annual Meeting of the Japan Pancreas Society (JPS) in Kyoto in July 2022. The presenters showed their indications for and results of surgical treatment for UR-M PDAC and discussed their advantages and disadvantages with the experts. Although these reports were limited to a small number of patients, findings suggest that these surgical treatments for patients with UR-M PDAC who have had a significant response to chemotherapy may contribute to a prognosis of prolonged survival. We hope that this article summarizing the discussion and agreements at the meeting will serve as the basis for future trials and guidelines.

"Conversion surgery" for locally advanced pancreatic cancer: A position paper by the study group at the joint meeting of the International Association of Pancreatology (IAP) & Japan Pancreas Society (JPS) 2022.

Locally advanced pancreatic cancer (LAPC), which progresses locally and surrounds major vessels, has historically been deemed unresectable. Surgery alone failed to provide curative resection and improve overall survival. With the advancements in treatment, reports have shown favorable results in LAPC after undergoing successful chemotherapy therapy or chemoradiation therapy followed by surgical resection, so-called "conversion surgery", at experienced high-volume centers. However, recognizing significant regional and institutional disparities in the management of LAPC, an international consensus meeting on conversion surgery for LAPC was held during the Joint Congress of the 26th Meeting of the International Association of Pancreatology (IAP) and the 53rd Annual Meeting of Japan Pancreas Society (JPS) in Kyoto in July 2022. During the meeting, presenters reported the current best multidisciplinary practices for LAPC, including preoperative modalities, best systemic treatment regimens and durations, procedures of conversion surgery with or without vascular resections, biomarkers, and genetic studies. It was unanimously agreed among the experts in this meeting that "cancer biology is surpassing locoregional anatomical resectability" in the era of effective multiagent treatment. The biology of pancreatic cancer has yet to be further elucidated, and we believe it is essential to improve the treatment outcomes of LAPC patients through continued efforts from each institution and more international collaboration. This article summarizes the agreement during the discussion amongst the experts in the meeting. We hope that this will serve as a foundation for future international collaboration and recommendations for future guidelines.

Withdrawal from Hemodialysis in a Patient with IgD Type Multiple Myeloma: A Case-based Review.

Several previous case reports have shown that patients with immunoglobulin D (IgD) multiple myeloma (MM) can be withdrawn from hemodialysis, however, the characteristics that can predict withdrawal in these patients have not yet been elucidated. A 57-year-old Japanese woman required hemodialysis because of renal dysfunction due to IgD-λ and Bence Jones protein-λ MM. Bortezomib-based chemotherapy nine days after admission led to her withdrawal from hemodialysis on Day 50. In our case-based review, younger age and early initiation of bortezomib-based chemotherapy emerged as possible predictors of successful hemodialysis withdrawal.

The academic impact and value of an international online surgery lecture series.

Due to the worldwide travel restrictions caused by the 2019 coronavirus disease pandemic, many universities and students lost opportunities to engage in international exchange over the past 2 years. Teleconferencing systems have thus been developed to compensate for severe travel restrictions. Kansai Medical University in Japan and Vilnius University in Lithuania have a collaborative research and academic relationship. The two universities have been conducting an online joint international surgery lecture series for the medical students of both universities. Fifteen lectures were given from October 2021 to May 2022. The lectures focused on gastrointestinal surgery, gastroenterology, radiology, pathology, genetics, laboratory medicine, and organ transplantation. A survey of the attendees indicated that they were generally interested in the content and satisfied with attending this lecture series. Our efforts were successful in providing Japanese and Lithuanian medical students with the opportunity to engage in international exchange through lectures held in each other's countries.

The degree of satisfaction and level of learning in male and female surgical residents: a nationwide questionnaire survey of graduating residents in Japan.

PURPOSE: Since 2002, the Japan Surgical Society has established a board certification system for surgeons to be certified for a specialty. Surgery remains a male-dominated field in Japan. This study aimed to clarify if the Japanese surgical residency training system is equally suitable for female and male residents. METHODS: The Japan Surgical Society conducted the first questionnaire survey regarding the system of surgical training for the residents in 2016. The questionnaire included the degree of satisfaction with 7 aspects of the training system, including the number and variety of cases experienced and duration and quality of instruction, and the learning level for 31 procedures. The degree of satisfaction and level of learning were compared between female and male residents. RESULTS: The degree of satisfaction was similar for all items between female and male residents. Female residents chose breast surgery as their subspecialty more frequently than male residents and were more confident in breast surgery procedures than male residents. Conversely, fewer female residents chose gastrointestinal surgery and were less confident in gastrointestinal surgery procedures than male residents. CONCLUSION: Female residents were as satisfied with the current surgical training system as male residents. However, there may be room for improvement in the surgical system, considering that fewer applications for gastrointestinal surgery come from female residents than from males.

Long-term outcomes of patients with multifocal intraductal papillary mucinous neoplasm following pancreatectomy.

BACKGROUND: The decision to perform surgery is complicated by the presence of multifocal (MF) intraductal papillary mucinous neoplasms (IPMNs), which are characterized by two or more cysts located in different areas of the pancreas. OBJECTIVES: We aimed to establish a suitable treatment strategy and surgical indications in patients with MF-IPMNs. METHODS: This single-center retrospective study included patients with IPMNs who underwent pancreatic resection from 2006 to 2020. Patients with distant metastasis and patients with IPMNs of the main pancreatic duct were excluded from the analysis. RESULTS: After excluding 22 patients, 194 patients were included. One hundred thirteen patients (58.2%) had unifocal IPMNs, while 81 patients (41.8%) had MF-IPMNs. There were no significant differences in the 5-year disease-specific survival (DSS) rate (92.3% vs. 92.4%, p = 0.976) and the 5-year disease-free survival rate (88.6% vs. 86.5%, p = 0.461). The multivariate analysis identified high-risk stigmata, invasive carcinoma, and lymph node metastasis as independent predictors of DSS. The presence of cystic lesions in the pancreatic remnant was not a predictor of survival. Even in the MF-IPMN group, there were no significant differences in DSS when stratified by procedure (total pancreatectomy vs. segmental pancreatectomy, p = 0.268) or presence of cystic lesions in the pancreatic remnant (p = 0.476). The multivariate analysis identified lymph node metastasis as an independent predictor of DSS in the MF-IPMN group. CONCLUSIONS: In patients with MF-IPMNs, each cyst should be evaluated individually for the presence of features associated with malignancy.

High tumor budding predicts a poor prognosis in resected duodenal adenocarcinoma.

PURPOSE: Tumor budding is a histological characteristic defined as the presence of small clusters of cancer cells at the invasion front. Its significance in duodenal adenocarcinoma (DA) has not been fully described. METHODS: A single-center, retrospective study was conducted. Patients who underwent curative surgery for histologically diagnosed DA from January 2006 to December 2018 at Kansai Medical University Hospital were included. Tumor budding was counted per 0.785 mm2 and classified as low (0-4 buds), intermediate (5-9 buds), or high (≥ 10 buds). RESULTS: In total, 47 patients were included. The 5-year overall survival and relapse-free survival rates were 77% and 72%, respectively. High tumor budding was seen in 15 patients (32%). Excluding patients with superficial type (pT1) DA (n = 22), high tumor budding [hazard ratio (HR) 13.4, p = 0.028], regional lymph node metastasis (HR 19.9, p = 0.039), and adjuvant chemotherapy (HR 0.056, p = 0.036) were independent factors related to the overall survival in multivariate analyses. Distant metastases occurred significantly more often in patients who had high tumor budding than in others (p = 0.039). CONCLUSION: The data suggest that high tumor budding is a predictor of a poor prognosis in resected DA.

Interdisciplinary Approach of Establishing PDAC Resectability: Biochemical, Radiological and NAT Regimen Prognostic Factors-Literature Review.

Background and Objectives: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal tumors, with a 5-year overall survival rate of less than 10%. To date, curative surgical resection remains the only favorable option for improving patients' survival. However, there is no consensus on which prognostic biochemical, radiological markers or neoadjuvant therapy regimens would benefit patients the most. Materials and Methods: A literature review was performed focusing on overall survival, R0 resection, 30-day mortality, adverse events (AEs), and elevated biomarkers. The electronic databases were searched from 2015 to 2020. Results: We reviewed 22 independent studies. In total, 20 studies were retrospective single- or multi-center reviews, while 2 studies were prospective Phase II trials. Conclusions: Patients with borderline resectable or locally advanced PDAC, who received neoadjuvant therapy (NAT) and surgery, have significantly better survival rates. The CA 19-9 biomarker levels in the neoadjuvant setting should be evaluated and considered as a specific biomarker for tumor resectability and overall survival.

Does direct invasion of peripancreatic lymph nodes impact survival in patients with pancreatic ductal adenocarcinoma? A retrospective dual-center study.

BACKGROUND: Pancreatic ductal adenocarcinoma can directly invade the peripancreatic lymph nodes; however, the significance of direct lymph node invasion is controversial, and it is currently classified as lymph node metastasis. This study aimed to identify the impact of direct invasion of peripancreatic lymph nodes on survival in patients with pancreatic ductal adenocarcinoma. METHODS: A total of 411 patients with resectable/borderline resectable pancreatic ductal adenocarcinoma who underwent pancreatic resection at two high-volume centers from 2006 to 2016 were evaluated retrospectively. RESULTS: Sixty (14.6%) patients had direct invasion of the peripancreatic lymph nodes without isolated lymph node metastasis (N-direct group), 189 (46.0%) had isolated lymph node metastasis (N-met group), and 162 (39.4%) had neither direct invasion nor isolated metastasis (N0 group). There was no significant difference in median overall survival between the N-direct group (35.0 months) and the N0 group (45.6 month) (p = 0.409), but survival was significantly longer in the N-direct compared with the N-met group (25.0 months) (p = 0.003). Similarly, median disease-free survival was similar in the N-direct (21.0 months) and N0 groups (22.7 months) (p = 0.151), but was significantly longer in the N-direct compared with the N-met group (14.0 months) (p < 0.001). Multivariate analysis identified resectability, adjuvant chemotherapy, and isolated lymph node metastasis as independent predictors of overall survival. However, direct lymph node invasion was not a predictor of survival. CONCLUSION: Direct invasion of the peripancreatic lymph nodes had no effect on survival in patients undergoing pancreatic resection for pancreatic ductal adenocarcinoma, and should therefore not be classified as lymph node metastasis.

Added Diagnostic Value of Cerebrospinal Fluid Carcinoembryonic Antigen in a Patient with Leptomeningeal Carcinomatosis as the Initial Manifestation of Gastric Cancer.

A 77-year-old woman with no history of malignancy presented with anorexia and bilateral lower extremity weakness. Her consciousness level worsened daily, so we performed a lumbar puncture. Cerebrospinal fluid (CSF) analysis indicated meningitis, but three rounds of CSF cytology showed no malignant cells. The patient's carcinoembryonic antigen (CEA) level was highly elevated in CSF, but normal in serum. Through gadolinium-enhanced brain/spinal magnetic resonance imaging and gastrointestinal endoscopy, she was diagnosed with leptomeningeal carcinomatosis (LC) from gastric cancer. CEA level in CSF facilitated the diagnosis of LC from gastric cancer because there were no malignant cells on CSF cytology.

Nutritional impact of active hexose-correlated compound for patients with resectable or borderline-resectable pancreatic cancer treated with neoadjuvant therapy.

Active hexose-correlated compound (AHCC) is a standardized extract from cultured Lentinula edodes mycelia, used as a potent biological response modifier in cancer treatment. We evaluated the nutritional effect of AHCC, given during neoadjuvant therapy, to patients with pancreatic ductal adenocarcinoma (PDAC). Thirty patients with resectable or borderline-resectable PDAC received neoadjuvant therapy with gemcitabine plus S-1. We compared, retrospectively, the outcomes of 15 patients who received AHCC combined with neoadjuvant therapy with those of 15 patients who did not receive AHCC combined with neoadjuvant therapy. The median changes of the neutrophil-to-lymphocyte ratio (NLR) and prognostic nutrition index (PNI) were significantly better in the AHCC group. The relative dose intensity of neoadjuvant therapy was also significantly higher in the AHCC group. Thus, AHCC may improve the nutritional status during neoadjuvant therapy of patients with pancreatic ductal adenocarcinoma. To validate these results and examine the long-term impact of AHCC, a prospective phase II study for PDAC is ongoing.

Is there disparity between regions and facilities in surgical resident training in Japan? Insights from a national survey.

PURPOSE: This study sought to assess the disparity between regions and facilities in surgical resident training in Japan via a national level needs-assessment. METHODS: A survey was sent to all 909 graduating residents of 2016. Residents trained in the six prefectures with a population of 7 million or more were included in the large prefecture (LP) group. Residents trained in the other 41 prefectures were included in the small prefecture (SP) group. Each group was further divided into a university hospital (UH) group and a non-university hospital (NUH) group. RESULTS: The response rate was 56.3% (n = 512). Excluding nine residents who did not report their prefectures and facilities, surveys from 503 residents were analyzed. The UH group received significantly more years of training. In the SP and UH groups, there were significantly fewer residents who had performed 150 procedures or more under general anesthesia in comparison to the LP and NUH groups, respectively. Self-assessed competencies for several procedures were significantly lower in the SP and UH groups. CONCLUSION: Disparity in surgical resident training was found between regions and facilities in Japan. The surgical residency curriculum in Japan could be improved to address this problem.

Are graduating residents sufficiently competent? Results of a national gap analysis survey of program directors and graduating residents in Japan.

PURPOSE: To evaluate the self-assessed competency of graduating residents (GRs) in Japan upon completion of their residency and to identify the gap between their competency and the competency expected by their program directors (PDs). METHOD: A list of 31 essential surgical procedures was compiled according to the consensus of surgical educators from around the country. A survey with this list was sent to all 909 GRs and their 611 PDs in 2016. The GRs rated their competency to perform these procedures and the PDs were asked to evaluate the expected competency of their GRs using the Zwisch Scale. RESULT: The response rate was 56.3% for the GRs and 76.8% for the PDs. Fewer than half of the GRs who responded felt confident performing ten (32%) of the surgical procedures evaluated. For most procedures, the GRs' self-reported competency was lower than the expectation reported by their PDs. This gap was more than 10% for 13 of the procedures. CONCLUSION: More than half of the GRs in Japan lacked the confidence in their skill to perform one-third of the surgical procedures selected for evaluation in this study. These findings should be used to update the surgical education curriculum in Japan.

A snapshot of surgical resident training in Japan: results of a national-level needs assessment survey.

PURPOSE: To evaluate the status of surgical training in Japan through a national-level needs assessment. METHODS: A survey was sent to all 909 graduating residents (GRs) and their 611 program directors (PDs) for the year 2016. A working group of surgical educators from around the country was formed under the education committee of the Japan Surgical Society. The survey items were developed by consensus of this working group. The survey investigated the knowledge and problems of the current curriculum, and the status of the current residency training. RESULTS: The response rates were 56.3% of the GRs and 76.8% of the PDs. Among the participants, 47.6% of the GRs and 29.4% of the PDs believed that the residency curriculum did not match the clinical experience. Over 80% of the GRs and PDs agreed on the importance of training outside of the OR, whereas only 13% of the GRs had received such training regularly. Trainees also reported a lower satisfaction rate about the opportunity to train outside of the OR. CONCLUSION: This national-level needs assessment of surgical training in Japan identified several gaps in the curriculum. These results provide valuable data to assist the ongoing efforts for surgical residency curriculum improvement.

Downregulation of 15-hydroxyprostaglandin dehydrogenase by interleukin-1ß from activated macrophages leads to poor prognosis in pancreatic cancer.

Chronic inflammation has a crucial role in cancer development and the progression of various tumors, including pancreatic ductal adenocarcinoma (PDAC). The arachidonate cascade is a major inflammatory pathway that produces several metabolites, such as prostaglandin E2. The enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) degrades prostaglandin and is frequently decreased in several types of cancer; however, the molecular mechanisms of 15-PGDH suppression are unclear. The current study was carried out to elucidate the molecular mechanisms and clinical significance of 15-PGDH suppression in PDAC. Here, we showed that interleukin-1ß (IL-1ß), a pro-inflammatory cytokine, downregulates 15-PGDH expression in PDAC cells, and that IL-1ß expression was inversely correlated with 15-PGDH levels in frozen PDAC tissues. We also found that activated macrophages produced IL-1ß and reduced 15-PGDH expression in PDAC cells. Furthermore, the number of CD163-positive tumor-associated macrophages was shown to be inversely correlated with 15-PGDH levels in PDAC cells by immunohistochemical staining of 107 PDAC samples. Finally, we found that low 15-PGDH expression was significantly associated with advanced tumors, presence of lymph node metastasis and nerve invasion, and poor prognosis in PDAC patients. Our results indicate that IL-1ß derived from TAMs suppresses 15-PGDH expression in PDAC cells, resulting in poor prognosis of PDAC patients.