CD48 and neoplasm: We analyzed the expression levels of genes encoding soluble immune checkpoint proteins, including CD48, B7-H2, TIMD-4, B7-H6, CD134, B7-H5, CD47, S100A8, and S100A9 (genes: CD48, ICOSLG, TIMD4, NCR3LG1, TNFRSF4, VSIR, CD47, S100A8, S100A9) in these tumor tissues.