FOSL2 belongs to the activator protein 1 (AP1) transcription factor family, which is expressed in various tissues and is involved in fat metabolism, bone development, and the pathogenesis of various diseases, such as cancer (Foletta et al., 1994; Chinenov and Kerppola, 2001; Eferl and Wagner, 2003). The gene discussed is FOS; the disease is cancer.