CD274 and familial pancreatic carcinoma: Subsequent immunohistochemistry staining further validated these results, showing that high levels of PD-L1 protein (staining frequency of grade 2 or higher) were observed in various cancer types: hepatocellular carcinoma (52.5%, 21/40), urothelial carcinoma (86.7%, 26/30), renal carcinoma (52.0%, 26/50), and pancreatic cancer (66.7%, 20/30).