For example, we found that PLK1 and HER2 kinase combination therapy was more effective in reducing viable cell numbers in HCC202 compared to MDA361 cancer cells (Fig. 3A, see 0.01 μM PLK1i dose) despite these two cell lines exhibiting similar sensitivity to lapatinib following exposure to fibroblast-conditioned medium. This evidence concerns the gene PLK1 and cancer.