Since the CDKN2 locus, which encodes p16 (INK4a) and p19 (ARF) genes, has been implicated in human and murine sarcoma pathogenesis, we also sought to determine if dysregulation of this tumor suppressor would play a cooperative role in sarcomagenesis in the RCAS-TVA system [14], [22]. Here, CDKN2A is linked to sarcoma.