SKP2 and osteosarcoma: FKA has been reported to inhibit cell proliferation in a dose-dependent manner by decreasing Skp2 protein post-translationally in numerous tumors(Table 2), including pRb-deficient prostate cancer cells, bladder cancer cell lines (Tang et al., 2008), HER2-overexpressing breast cancer cell lines (Jandial et al., 2017), synovial sarcoma cell lines (Wang J. et al., 2020), and osteosarcoma cell lines (Zhang et al., 2018).