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. This evidence concerns the gene CCL18 and ovarian cancer.