After establishing a prognostic model, we divided SCLC samples into high- and low-risk groups based on the median value of the risk score of the risk assessment model, and the results implied that the HLAs, especially HLA-DPA1, HLA-DPB1, HLA-DMB, and HLA-DOA, were remarkably upregulated in the low-risk group. The gene discussed is HLA-DMB; the disease is small cell lung carcinoma.