POLH and cancer: To that end we used the TCGA database and first analyzed, for each cancer type, the percentage of the samples that contained mutations in at least one of the genes that we defined as a TLS-related genes group, containing TENT4A, CYLD, NPM1, TENT4B, PAXIP1, PCNA, POLH, POLI, POLK, PRIMPOL, RAD18, REV1, REV3L and USP1. As can be seen in Supplementary Materials Table S11, there is a big variation in the percent of samples with mutations in the TLS genes group, ranging from about 1–2% (e.g., Thyroid Carcinoma; THCA) up to 37% for Uterine Corpus Endometrial Carcinoma (UCEC; endometrial cancer).