NRAS and cancer: In addition, the mutation rate of RAS genes (KRAS and NRAS) was 40% (8/20), which was basically consistent with the tissue mutation rate of CRLM patients.[23, 24] Similarly, using the cancer driver gene database,[25] we also found that the mutation pattern of cancer driver genes in CRLM PDOs was highly consistent with paired tumor (Figure S5, Supporting Information), although it was noted that CRLM PDOs could acquire new mutational fingerprints or lose genetic information from parental sources.