XP-C cancers contained somatic copy number aberrations (SCNAs) and mutations which are characteristic for corresponding types of sporadic malignancies: mutations in TP53 and deletions of chromosomes 5 and 7 in leukemia, biallelic loss of CDKN2A in breast cancer and highly unstable genome of rhabdomyosarcoma (Supplementary Table 1). The gene discussed is CDKN2A; the disease is breast carcinoma.