HLA-C and neoplasm: Besides, tumor-suppressive M1 macrophages were found to be enriched in HCC patients with higher C2 expression in the TCGA cohort, which may contribute to better prognosis of HCC patients as studies have showed that M1 macrophages are involved in killing pathogens and tumor cells by producing large amounts of proinflammatory cytokines and expressing MHC molecules [27].