GNAS gene mutation may be present only transiently during colorectal tumorigenesis.

Mutations of the gene GNAS have been shown to activate the adenylate cyclase gene and lead to constitutive cAMP signaling. Several preliminary reports have suggested a role for GNAS gene mutations during colorectal carcinogenesis, particularly mucinous carcinomas. The aim of this study was to clarify the incidence of GNAS mutations in adenomas (tubular, tubulovillous, and villous), carcinomas with residual adenoma, and carcinomas, and to relate these findings to mutations of the KRAS gene and to the mucinous status of the tumors.

Detailed molecular genetics of the APC*E1317Q mutation in tumor tissue suggest it may not be pathologically significant.

APC*E1317Q is a low-penetrance variant of the APC gene suggested as a risk for the development of colorectal adenomas and carcinomas. There is very little in the literature describing the molecular details of APC*E1317Q in tumor tissue. We provide information about the molecular genetics of 3 patients with APC*E1317Q.

Microsatellite instability and DNA methylation of endometrial tumors and clinical features in young women compared with older women.

Introduction: Molecular genetic changes in endometrial cancers are important to identify possible family cancer syndromes and thus, to facilitate appropriate screening. Most studies in this regard have focused primarily on young women. We have assayed cancers for microsatellite instability (MSI) and DNA methylation from a large group of patients younger than 50 years and a comparable group of older women.

The Adenomatous Polyposis Coli (APC) gene microsatellite marker D5S1385 is equally informative for loss of heterozygosity as the marker D5S346.

Molecular analyses for loss of heterozygosity (LOH) at a gene locus are used to identify genomic imbalance in tumor tissue. A frequently utilized microsatellite marker for the Adenomatous Polyposis Coli (APC) gene is denoted D5S346. However, when an individual has two identical forms of this microsatellite, then a second microsatellite, also near the APC gene, is needed.

The characterization of somatic APC mutations in colonic adenomas and carcinomas in Ashkenazi Jews with the APC I1307K variant using linkage disequilibrium.

Mutations of the adenomatous polyposis coli (APC) gene play a critical role in the development of colorectal neoplasms. A novel mechanism involves a germline variant, at codon 1307 of the APC gene. The mutation is thought to create an unstable segment of DNA, which facilitates the development of somatic mutations.