Although no significant difference in HLA expression was observed between patients with multiple ENI and those without ENI and with single ENI, loss of HLA‐A, HLA‐B, and HLA‐C was associated with ENI‐related mutations, namely HLA‐A with mutations of SGK1 and HIST1H1E, HLA‐B with mutations of MYD88, PIM1, and TBL1XR1, and HLA‐C with mutations of FOXO1 and ARID1A, indicating possible role of alterations in MHC class I expression on immune surveillance by anti‐tumor T cells in DLBCL. The gene discussed is ARID1A; the disease is neoplasm.