ERCC2 and urinary bladder carcinoma: We observed that the expression levels of both AHNAK and ERCC2 were significantly lower in Asian than those in White population (P < 0.05 and P < 0.001, respectively) (Fig. S6), which provided further evidence supporting that racial differences in the activities of AHNAK and ERCC2 might contribute to the observed racial differences in the prevalence of APOBEC‐a and ERCC2 & AGE signatures in bladder cancer.