CHD5 and lung cancer: KDM4A is aberrantly expressed in lung carcinoma and mediates tumorigenesis by modulating the transformation, proliferation, invasion, and metastasis of cancer cells.55, 56, 57, 58, 59, 60, 61, 62, 63 In the human lung cancer cell line A549, KDM5A collaborates with oncogenic K-Ras to promote cellular transformation by down-regulating tumor suppressor chromodomain helicase DNA binding protein 5 (CHD5),63 a gene activating p53 signaling by targeting p19ARF and impeding p53 ubiquitination degradation.64