Among HLA class II genes, LOH events were recurrently detected across multiple cancer types, with 67 (16.7%), 65 (15.6%) and 62 (15.5%) tumors exhibiting LOH in HLA-DQA1, -DRB1, and -DQB1 genes, respectively; 42 (11.0%) cases had LOH in all three genes, including nine (20.9%) Ewing sarcoma, five (35.7%) LGG, and four (22.2%) GBM tumors. The gene discussed is HLA-DRB1; the disease is Ewing sarcoma.