We found that NU5455 also induced a significant sensitizing effect to doxorubicin in colorectal cancer (HCT116) and HCC (Hep3B and Huh7) cell lines with an LD80 sensitization ranging from 3.1- to 5.1-fold, but with no effect in PRKDC–/– cells, which do not express DNA-PK (Figure 6B and Supplemental Figure 14). The gene discussed is PRKDC; the disease is colorectal cancer.