REV1 and cancer: In addition, our results presented in Table 6 show that expression of all five candidate genes was correlated with sensitivity to chemotherapy and that log(IC50) of a number of antitumor agents was significantly correlated not only with expression levels of APOBEC3B, but also with those of APOBEC3A, REV1 UNG, and FHIT. Three of these genes, REV1, UNG, and APOBEC3A, were also associated with overall mutation activity and/or with prevalence of APOBEC-like motifs and kataegis clusters in specific cancer types.