After a preselection step using univariate Cox analysis, the expression levels of 3220 ERVs from samples in the training set were used to build a 29-ERV prognosticator of BCR using a Lasso-Cox proportional hazards model, and the final risk-prediction model was built by combining this panel of 29 markers with the available clinical data, including Gleason value, PSA, age, and tumor stage (Table S6). This evidence concerns the gene KLK3 and neoplasm.