Plasma lipid levels are associated with the CD8+ T-cell infiltration and prognosis of patients with pancreatic cancer.

Abstract

Recently, researchers have found that the tumour microenvironment plays an important role in tumours. We aimed to investigate the effects of plasma lipids on the prognosis of patients with pancreatic cancer and the infiltration of CD8+ T lymphocytes in tumour tissue. We enrolled patients with pancreatic ductal adenocarcinoma (PDAC) who underwent pancreatic surgery between 2012 and 2021. Clinical pathological data were recorded; total cholesterol (TC) and triglyceride (TG) levels were measured; and tissue samples were collected. A tissue microarray was generated using collected tissue samples, and CD8 staining was performed to determine immunoreactive scores (IRSs). The correlations of TC and TG levels with clinicopathological characteristics and prognosis were analysed. Finally, the correlations of TC and TG levels with CD8+ T-cell infiltration were analysed. A total of 90 eligible PDAC patients were included. TC levels were significantly correlated with tumour grade and lymph node metastasis, and TG levels were significantly correlated with perineural invasion. The Kaplan-Meier survival analysis results indicated that the prognosis in the high TC group was significantly worse than that in the low TC group, and the prognosis in the high TG group was significantly worse than that in the low TG group. Cox multivariate analysis indicated that TC was an independent indicator of poor prognosis of pancreatic cancer patients after surgery. Spearman correlation analysis indicated that there were significant negative correlations between CD8 IRS and TC and between CD8 IRS and TG. TC and TG levels are significantly related to the prognosis of pancreatic cancer patients. They may be associated with tumour progression to higher grades, lymph node metastasis and/or nerve invasion. More importantly, TC and TG may reduce CD8+ T lymphocyte infiltration into pancreatic cancer tissue, affecting antitumour immune functions and immunotherapy efficacy.