In our samples, the expression levels of APOBEC3B and APOBEC3C were significantly higher in tumours than in paired normal tissues (P=8.81 × 10−31 and P=3.21 × 10−5, respectively, unpaired t-test; Supplementary Fig. 2d) and strongly correlated with the total number of the C>T (P=0.022, Spearman's r=0.24) and C>G (P=0.019, Spearman's r=0.24) mutations at TpCpW trinucleotide sites, respectively (Supplementary Fig. 2d). This evidence concerns the gene APOBEC3B and neoplasm.