Impact of the tumor immune microenvironment on the outcome of pancreatic cancer: a retrospective study based on clinical pathological analysis.

Abstract

The cancerous microenvironment, characterized by the infiltration of CD4+ and CD8+ T cells, play a critical role in regulating the progression of cancer and treating efficiency of immunotherapy. However, the distribution of these cells and their associated cytokines in the tumor microenvironment of pancreatic cancer (PC) are not yet fully understood. Our study aims to analyze the contents of CD4+IL-17+ and CD8+ T cells in PC and their relationship with the clinicopathological features and survival outcomes of patients. PC tissues and adjacent tissues were retrospectively collected from 40 patients in our hospital. The expression of CD4, IL-17, and CD8 in histological samples was measured by immunohistochemistry. The correlation between CD4, IL-17, and CD8 expression and clinical characteristics was analyzed using Kaplan-Meier survival analysis. The risk factors affecting the outcome of PC were examined by the Cox proportional hazards model, then a nomogram predicting the survival of PC using these risk factors was established. The content of CD4+IL-17+ T cells in PC tissues was significantly higher than that in adjacent normal tissues, while the number of CD8+ T cells was significantly lower than that in adjacent normal tissues (P<0.01). CD4+ T cells in PC tissues was significantly associated with TNM stage and lymph node metastasis (P<0.05). IL-17 and CD8 were significantly associated with histological grade, TNM stage, local infiltration, and lymph node metastasis (P<0.05). The median survival times (MSTs) of CD4 positive and negative patients were 13.2 and 21.4 months, respectively. The MSTs of IL-17 positive and negative patients were 10.4 and 24.8 months, respectively. The MSTs were 21.9 and 11.8 months for CD8 positive and negative patients, respectively (P<0.05). The Cox regression model demonstrated that TNM staging, lymph node metastasis, and CD4+IL-17+ and CD8+ T cells affected PC prognosis (P<0.05). The nomogram showed that the survival probability was reduced in patients with TNM stage III to IV, lymph node metastasis, high CD4+IL-17+ level, and low CD8+ expression. CD4+IL-17+ and CD8+ T cells in PC tissues are associated with TNM staging, lymph node metastasis, and MST, and can be used as new prognostic indicators for PC.