PLK1 and cancer: Also, we used four untransformed cell lines and 28 cancer cell lines with different genotypes, including KRAS mutation, NRAS mutation, epidermal growth factor receptor (EGFR) mutation, and KRAS wild-type, to verify the synergistic effect of the synthetic lethal genes polo-like kinase 1 (PLK1) and RhoA/Rho kinase (ROCK).