SIPA1 and prostate cancer: Signal-induced proliferation-associated 1 (SIPA1), a member of Rap1GAP family (Wada et al., 1997), is aberrantly expressed in breast cancer, colorectal cancer, melanoma and prostate cancer cells, participating in the regulation of tumor cell proliferation, adhesion, invasion and metastasis (Shimizu et al., 2011; Ji et al., 2012; Mathieu et al., 2012; Zhang et al., 2015).