JMJD5 (Jumonji domain-containing protein 5) or commonly called as Lysine-specific demethylase 8 is a histone lysine demethylase that specifically demethylates dimethylated Lys 36 of histone H3 (H3K36me2) thereby activating the target gene. JMJD5 is important for G2/M phase cell cycle progression. JMJD5 is also a potential tumor suppression protein. JMJD5 helps in regulation of cancer proliferation by regulating cyclin-A1. JMJD5 has three isoforms (47, 24, 50 kDa), all localized in nucleus. JMJD5 is weakly expressed in most normal cells but highly expressed in breast cancer cells.