ATR and head and neck cancer: Figure 1B represents the somatic mutation in 17 TCGA cancer types. We considered genes having mutation in at least 1% samples in a given cancer, and present in any two or more cancers, resulting in 72 genes. Of all DDR genes, TP53 was the most frequently mutated gene. The other frequently mutated DDR genes were PRKDC, ATM, BRCA2, POLE, ATR, BRCA1, and FANCM. Among the 17 cancer types, uterine corpus cancer (UCEC), head and neck cancer (HNSC), and skin cutaneous melanoma (SKCM) had most frequent alterations in DDR genes.