PLK1 and cancer: There were 40 pathways enriched based on the above 605 DEGs and 55 DEMs (Supplementary Table 4, P < 0.05) including “Cell cycle,” “Neuroactive ligand-receptor interaction,” “Transcriptional misregulation in cancer,” “Progesterone-mediated oocyte maturation,” “FoxO signaling pathway.” Further analysis found that upregulated genes Bcl6, Bnip3, Cdkn1a, Gabarapl1, Gadd45b, Irs2 and downregulated genes Ccnb2, Mapk11, and Plk1 in microgravity group were enriched in FOXO signaling pathway.