Kras mutation correlating with circulating regulatory T cells predicts the prognosis of advanced pancreatic cancer patients.

Abstract

PurposeKras mutation and abnormal immune status are associated with pancreatic cancer development and progression. In this study, we evaluated the Kras mutation status in circulating tumor DNA and circulating T cell subsets in a cohort of advanced pancreatic cancer patients.MethodsSamples were retrospectively obtained from a series of 210 pathological advanced pancreatic cancer patients between 2012 and 2014. The Kras mutation status was detected in cell‐free circulating tumor DNA (ctDNA) by ddPCR and circulating T cell subsets were analyzed by flow cytometry.ResultsUnivariate analysis found that tumor node metastasis (TNM) stage, chemotherapy, circulating regulatory T cells, CA19‐9 levels, CA125 levels, and KrasG12D and KrasG12V mutations were significantly related to overall survival in advanced pancreatic cancer patients. Multivariate analysis identified that TNM stage (P = .03, HR:1.422), Tregs (P = .004, HR:1.522), CA19‐9 levels (P = .009, HR:1.488), KrasG12D mutation (P = .044, HR:1.353), and KrasG12V mutation (P = .001, HR:1.667) were independent prognostic markers. Furthermore, we found that KrasG12V mutation in ctDNA was correlated with high circulating proportion of Tregs, and patients with both KrasG12V mutation and high levels of Tregs were associated with extremely poor survival in advanced pancreatic cancer.ConclusionKrasG12V mutation was associated with high circulating regulatory T cell levels, and both of them predicted worse prognosis in advanced pancreatic cancer patients.