HLA-G and neoplasm: Moreover, this outcome fits with the concept that tumor cells are positively selected based on low- or no expression of classical HLA, caused by genetic alterations like HLA class I allele-specific mutations, β2-microglobulin gene mutations, and antigen processing machinery-associated mutations [19, 22, 46, 47], and can be linked to invasiveness and metastatic potential [16, 48–50].