Among individual cancer types, we observed a strong (ρ between − 0.738 and − 0.902) and statistically significant (padj < 0.05) negative correlation of the frequencies of C>T, C>G, and C>K substitutions and overall nucleotide substitution counts with REV1 expression in sarcoma and UNG expression in melanoma (Table 5). Here, REV1 is linked to cancer.