Increased expression of KDM5A (Sharma et al. 2010) and KDM5B (Roesch et al. 2013) have previously been found to be functionally important markers of slow cycling cancer cells that are enriched upon drug exposure, whereas the pre-existing KDM5Bhigh subpopulation was also found to be essential for continuous tumor growth in melanoma (Roesch et al. 2010). Here, KDM5B is linked to neoplasm.