For example, the five-immune-related-gene prognostic signature model (CCL18, CXCL13, HLA-DOB, HLA-DPB2, and TNFRSF17) constructed with lasso regression based on the TCGA ovarian cancer database was verified with a GEO ovarian cancer dataset, and these genes were scientifically rationalized in the biological system of ovarian cancers as described in the section of discussion. The gene discussed is HLA-DOB; the disease is ovarian cancer.