Also, the recent study about SIGLEC15 additionally demonstrated the similar structure of SIGLEC15 and PDL1, which makes us wonder whether SIGLEC family genes expressed on tumor cells may directly influence immune cell infiltration and function in tumor microenvironment by binding to potential targets on immune cells, since SIGLEC15 has a relatively conservative structure among them (15, 43–45). This evidence concerns the gene SIGLEC15 and neoplasm.