Abstract
BACKGROUND: Immune responses have long been an area of interest in cancer research. In this study, the effects of programmed cell death-1 (PD-1) and its ligand (PD-L2) on the prognosis of colorectal cancer (CRC) were investigated. METHODS: Primary tumour specimens of stage III CRC patients operated between 2002 and 2013 were assessed for PD-1 and PD-L2 expression and various clinicopathological and prognostic factors. RESULTS: We observed a significant relationship between poor prognostic factors and PD-1/PD-L2 expression. These biomarkers were also found to serve as independent risk factors for LIR and MSI. In univariate analysis, relapse-free survival (RFS) and overall survival (OS) rates were found to be poor in PD-1 and PD-L2 positive patients. In multivariate analysis, these biomarkers were found to serve as independent poor prognostic factors for RFS and OS. CONCLUSIONS: Our data indicate that PD-1 and PD-L2 may serve as independent prognostic survival parameters for CRC patients and may be employed for the design of targeted therapies.