CLOCK and neoplasm: In most tumours, the majority of single base substitutions (SBS) could be assigned to signatures SBS5/SBS40 and SBS1 (using nomenclature established in ref.35), thought to result from endogenous clock-like mutagenic processes (Supplementary Fig. 8); however only SBS5 and the number of C > T mutations at NpCpG trinucleotides correlated with age (p = 4.3 × 10−8 and p = 0.02, respectively; Supplementary Fig. 9).