HLA-DPA1 and cancer: We noticed that some MHC class II genes (HLA-DMA, HLA-DPA1, HLA-DPB1, HLA-DRA, HLA-DRB1) were significantly down-regulated in cancer cells with relatively poor differentiation states compared with those with better differentiation states for 5/6 mGC patients (Fig. 4A and Fig. S10A; Table S5).