Mass spectrum analysis of membrane proteins reveals that CASK, CD36 and EPB42 are differentially expressed in pancreatic adenocarcinoma

Pancreatic cancer is one of the most life-threatening malignancies worldwide. Despite advances in checkpoint immunotherapy for patients with cancer, the current immunotherapies have demonstrated limited benefits for the treatment of pancreatic cancer. Apart from the intricate microenvironments that restrict T-cell function, membrane proteins other than programmed death-ligand 1 may also facilitate immune escape of tumor cells. The present study investigated the membrane proteins of seven paired pancreatic adenocarcinoma (PAAD) and adjacent normal tissues with mass spectrometry, and identified 10 up-and eight downregulated membrane proteins in PAAD. Together with the online database analysis, the results showed that the CASK protein was upregulated in PAAD samples and cell lines, and predicts poor outcomes in patients with PAAD. Furthermore, the results exhibited downregulated CD36 and EPB42 in PAAD samples and cell lines, and higher levels of CD36. EPB42 was shown to predict improved survival outcomes in patients with PAAD. Overall, the results of the present study revealed PAAD-specific membrane proteins as potential diagnostic markers and drug-targets for the immunotherapy of pancreatic cancer.