Article: article from journal or magazin.
Diagnostic utility of MS-MLPA in DNA methylation profiling of adenocarcinomas and neuroendocrine carcinomas of the colon-rectum.
Virchows Archiv : An International Journal of Pathology
Publication types: Journal ArticlePublication Status: ppublish
Methylation-specific multiple ligation-dependent probe amplification (MS-MLPA) is a fast, new, inexpensive method that has rarely been exploited in DNA methylation profiling of colorectal cancers (CRCs). The aim of this study was to test the diagnostic utility of MS-MLPA to evaluate the methylation status of 34 genes in normal colonic mucosa samples and in a well-characterized series of 83 adenocarcinomas and 21 neuroendocrine carcinomas of colon-rectum. Two commercial MS-MLPA kits (SALSA MS-MLPA ME001-C1 Tumor suppressor-1 Kit and SALSA MS-MLPA ME002-B1 Tumor suppressor-2 Kit) were used to perform promoter methylation analysis on formalin-fixed and paraffin-embedded tissues. MS-MLPA analysis was validated by bisulfite pyrosequencing, bisulfite cycle sequencing, and methylation-specific PCR. MS-MLPA analysis identified a subset of 27 CRCs (26 % of cases) showing high levels of gene methylation involving a mean percentage of 34 % of the promoters examined. These tumors exhibited all the main clinicopathological and genetic features described for CRCs with CpG island Methylator Phenotype-High. High levels of methylation were observed with similar frequency in adenocarcinomas and in neuroendocrine carcinomas (25 % versus 29 %, respectively), but different methylation profiles were observed in the two tumor types. In both groups, tumors with microsatellite instability and widespread methylation represented a homogeneous clinicopathological entity. MS-MLPA assay is an easy and reliable system for epigenetic characterization of tumor tissues and leads to a rapid identification of CRCs with the highest levels of gene methylation. Aberrant gene methylation is a common abnormality in CRC initiation and may be observed in tumors with very different genetic and clinicopathological profiles.
Adenocarcinoma/diagnosis, Adenocarcinoma/genetics, Adult, Aged, Aged, 80 and over, Carcinoma, Neuroendocrine/diagnosis, Carcinoma, Neuroendocrine/genetics, Colorectal Neoplasms/diagnosis, Colorectal Neoplasms/genetics, CpG Islands/genetics, DNA Methylation, DNA, Neoplasm/genetics, Female, Gene Expression Profiling, Humans, Male, Middle Aged, Neoplasm Staging, Nucleic Acid Amplification Techniques, Oligonucleotide Array Sequence Analysis, Tumor Suppressor Proteins/genetics
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