PLK1 and cancer: Especially, four of six cancer risk pathways: “APC-C-mediated degradation of cell cycle proteins pathway”, “Cyclin B2 mediated events pathway”, ”PLK1 signaling events pathway” and “Mitotic Prometaphase pathway” were enriched in “Hallmark mitotic spindle” and “Hallmark spermatogenesis”, these two hallmark-associated GO terms were important for cell division27 and development28.