Our data showed that tumour infiltrating inflammatory and immune cells may play a pivotal role in ECC progression and a high-risk signature predicted poor prognosis in ECC patients.

No abstract

Results Elevation of serum alanine aminotransferase (ALT) was found in 13 out of 25 (52%), all of whom were categorized as AN. In 13 AN patients with elevated ALT, the median of serum ALT values was 92 [39-438] IU/L. The body mass index (BMI) was significantly lower (13.5 vs. 17.3, p=0.011), and the duration since the onset of AN was shorter (4.2 years vs. 8.9 years, p=0.037) in patients with elevated ALT. The age was younger in patients with elevated ALT, even though not significant (24.5 vs. 29.8, p=0.139). Logistic regression analysis revealed that only BMI was a significant determinant for the development of hepatocellular injuries (OR=3.46; p=0.041

Immunotherapy using anti‐PD‐1/PD‐L1 antibodies for several types of cancer has received considerable attention in recent decades. However, the molecular mechanism underlying PD‐L1 expression in pancreatic ductal adenocarcinoma (PDAC) cells has not been clearly elucidated. We investigated the clinical significance and regulatory mechanism of PD‐L1 expression in PDAC cells. Among the various cytokines tested, tumor necrosis factor (TNF)‐α upregulated PD‐L1 expression in PDAC cells through NF‐κB signaling. The induction of PD‐L1 expression was also caused by co‐culture with activated macrophages, and the upregulation was inhibited by neutralization with anti‐TNF‐α antibody after co‐culture with activated macrophages. PD‐L1 expression in PDAC cells was positively correlated with macrophage infiltration in tumor stroma of human PDAC tissues. In addition, survival analysis revealed that high PD‐L1 expression was significantly associated with poor prognosis in 235 PDAC patients and especially in patients harboring high CD8‐positive T‐cell infiltration. These findings indicate that tumor‐infiltrating macrophage‐derived TNF‐α could be a potential therapeutic target for PDAC.

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‐1β (IL‐1β), a pro‐inflammatory cytokine, downregulates 15‐PGDH expression in PDAC cells, and that IL‐1β expression was inversely correlated with 15‐PGDH levels in frozen PDAC tissues. We also found that activated macrophages produced IL‐1β 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‐1β derived from TAMs suppresses 15‐PGDH expression in PDAC cells, resulting in poor prognosis of PDAC patients.