EGFR and cancer: Cheung et al. used the CRISPR/Cas9 system to target the point mutation L858R of EGFR (Cheung et al., 2018), the study used PAM to distinguish cancer mutations from normal mutations, providing high specificity in the degree of single nucleotide substitutions, and observed reduced expression of EGFR and inhibited cell proliferation in cells harboring the L858R mutation, providing novel insights into using CRISPR/Cas9 to selectively eliminate oncogenic mutations for cancer treatment.