BAC CGH array profiling using Phi29-amplified colon mucosa of microdissected samples from APC and MYH mutation carriers

Details of the series are available in the publication Cardoso J. et al., “Chromosomal instability in MYH- and APC-mutant adenomatous polyps”, Cancer Research, accepted for publication. Abstract of the publication: “The vast majority of colorectal cancers display genetic instability, either in the chromosomal (CIN) or microsatellite (MIN) forms. While CIN tumors are per definition aneuploid, MIN colorectal cancers, caused by loss of mismatch repair function, are usually near-diploid. Recently, bi-allelic germline mutations in the MYH gene, were found to be responsible for MAP (MYH associated polyposis), an autosomal recessive predisposition to multiple colorectal polyps, often indistinguishable from the dominant FAP (familial adenomatous polyposis) syndrome caused by inherited APC mutations. Here, we analyzed MYH- and APC-mutant polyps by combining laser-capture microdissection, isothermal genomic DNA amplification, and array-CGH (comparative genomic hybridization). Smoothed quantile regression methods were applied to the MAP and FAP genomic profiles to discriminate chromosomes predominantly affected by gains and losses. Up to 80% of the MAP polyps showed aneuploid changes, which is significantly higher than the 60% found among FAP polyps. Both MAP and FAP adenomas were characterized by frequent losses at chromosome 1p, 17, 19 and 22, and gains affecting chromosome 7 and 13. The observation that aneuploidy is already detectable at early stages of MYH-driven tumorigenesis raises the possibility that CIN may contribute significantly to accelerated tumor progression, increased cancer risk, and poor prognosis in MAP.” Details of the series are available in the publication Cardoso J. et al., “Chromosomal instability in MYH- and APC-mutant adenomatous polyps”, Cancer Research, accepted for publication.