POLK and cancer: Finally, to investigate whether the association between increased POLQ expression and increased somatic mutation load is also common in other human cancers and, if so, whether such an association is specific among various TLS polymerase genes [30], we used the TCGA dataset to examine the mRNA expression levels of 10 TLS polymerase genes (POLB, POLH, POLI, POLK, POLL, POLM, POLN, REV1, REV3L, and POLQ; Supplementary Table S1) and total number of somatic mutations across a panel of 18 distinct cancer types, including LAC.