Background: Colorectal cancer is the third most common cancer and requires more prognostic biomarkers for precise treatment. GPR39 is a GPCR which can interact with Zn and modulate the colonocytes' survival. The clinical significance of GPR39 in colon cancer has never been reported.
Materials: In our study, we compared GPR39 expression between colon cancers and tumor-adjacent tissues by retrieving TCGA data and detected the expression of GPR39 in colon cancers with qPCR and immunohistochemistry. The clinical significance of GPR39 was evaluated by analyzing the correlations with clinicopathological factors with the chi-square test. The prognostic significance of GPR39 was estimated with univariate and multivariate analyses. The expression of several other biomarkers including PPARG, EPCAM, and PD-L1 was investigated by re-analyzing TCGA data, qPCR, and IHC. The prognostic value of PPARG, EPCAM, and PD-L1 was also estimated with univariate analysis.
Results: In both TCGA database and our 15 colon cancer pairs, GPR39 expression was significantly upregulated in colon cancer tissues. GPR39 was an independent prognostic biomarker in colon cancer for poor prognosis. With TCGA data re-analysis, qPCR, and IHC, we showed that GPR39 expression was significantly correlated with the expression of EPCAM and PD-L1, but not PPARG. EPCAM and PD-L1 were also unfavorable prognostic biomarkers of colon cancer.
Conclusions: GPR39 was upregulated in colon cancer tissues compared with tumor-adjacent tissues. GPR39 was an independent prognostic biomarker in colon cancer for poor prognosis. EPCAM and PD-L1 were substantially associated with GPR39 expression, and they were also identified as prognostic biomarkers in colon cancers.
Keywords: Biomarker; Colon cancer; GPR39; PD-L1; Prognosis.
© 2021. The Author(s), under exclusive licence to Royal Academy of Medicine in Ireland.