PLK1 and cancer: Previous publications reported somewhat inconsistent effects of plk1 inhibition (Lénárt et al, 2007; Gheghiani et al, 2017), therefore we first wanted to compare side-by-side three cell lines that are most commonly used in cell cycle studies: two cancer cell lines, HeLa and U2-OS, and an hTERT immortalized non-cancer cell line, hTERT-RPE1.