Although the consistent expression of KDM5B in breast cancer was established by Lu P.J. et al. [22] in 1999, Yamane K. et al. in 2007 revealed the salient role of KDM5B in breast cancer cell proliferation via the transcriptional repression of tumor suppressor genes, including BRCA1 [19]. The gene discussed is KDM5B; the disease is breast carcinoma.