PLK1 and cancer: Furthermore, we have recently demonstrated that jerantinine A and B and the acetate derivative inhibited tubulin polymerization, polo-like kinase 1 (PLK1) activity and induced G2/M cell cycle arrest in a panel of human cancer cell lines consisting of vincristine-resistant nasopharyngeal carcinoma cells25, as well as breast, colorectal, lung and pancreatic carcinoma cells27, 28.