CSMD1 and cancer: Of the other eight genes, one is a tumor suppressor that is known to be inactivated by other genetic mechanisms [26] (MEN1), and four are candidate tumor suppressors based on either mutational analysis (CSMD1[27]), functional analysis (CDKN2AIP/CARF[28], MAD1L1[29]), or cancer-specific promoter hypermethylation (RRAD[30]).