PLK1 and neoplasm: Microinjection of PLK1 mRNA into NIH3T3 fibroblasts can induce tumor formation in nude mice, while transfection of PLK1 in human prostate epithelial cells can result in malignant transformation in vitro and promotes tumor formation in mouse models, indicating the crucial role of PLK1 in tumorigenesis (Smith et al., 1997; Wu et al., 2016).