ADAM21 and cancer: These genes include kallikrein related peptidases-3 and -7 (KLK3 and KLK7), a disintegrin and metallopeptidase domain 21 (ADAM21), hypermethylated in cancer (HIC1), retinoic acid receptor beta (RARB), secreted frizzled receptor 5 (sFRP5), corticotropin releasing hormone (CRH), PRKC apoptosis WT1 regulator (PAWR), and adenosine A2a receptor (ADORA2A).