Impact of CKLF-like MARVEL Transmembrane Domain Containing 6 (CMTM6) Expression in Gastric Cancer
Abstract Background: CKLF-like MARVEL transmembrane domain containing 6 (CMTM6) is the master regulator of programmed cell death-ligand 1(PD-L1). We aimed to clarify the significance of CMTM6 expression in gastric cancer (GC). Methods: A total of 105 patients who had undergone curative surgical resection for stage II/III GC at Tokushima University Hospital were included in this study. The expression of CMTM and PD-L1 was examined by immunohistochemistry. Additionally, the relationship of each expression level to several prognostic factors was examined using univariate and multivariate analyses. Results: CMTM6 was not positively correlated with any of the factors examined. The overall survival (OS) rates were significantly poorer in the CMTM6 high-expression group than in the CMTM low-expression group (5-year OS: 57.2% vs. 79.2%, respectively; p<0.05). Disease-free survival (DFS) was significantly poorer in the CMTM high-expression group than in the CMTM6 low-expression group (5-year DFS: 52.8% vs. 72.4%, respectively; p=0.20). Multivariate analysis confirmed CMTM6 expression as an independent prognostic factor in DFS (p<0.05). CMTM6 expression tended to be correlated with PD-L1 expression (p=0.07), and PD-L1 expression was positively correlated with PD-1 expression (p<0.05).Conclusions: CMTM6 is associated with a poor prognosis and immunotolerance through PD-L1 in GC.