Frequency of deletions of EPCAM (TACSTD1) in MSH2-associated Lynch syndrome cases.

Lynch syndrome is an autosomal dominant cancer predisposition syndrome characterized by loss of function of DNA mismatch repair enzyme MLH1, MSH2, MSH6, or PMS2. Mutations in MLH1 and MSH2 account for ∼80% of the inherited cases. However, in up to 20% of cases suspected of having a germline mutation in MSH2 due to loss of MSH2 expression, a germline mutation is not identified.

Alpha-1-antitrypsin deficiency and smoking as risk factors for mismatch repair deficient colorectal cancer: a study from the colon cancer family registry.

In a previous study, alpha-1-antitrypsin (A1AT) deficiency alleles were found to be over represented among individuals with microsatellite unstable (MSI-high) colorectal cancers, and this was most significant in former or current smokers. We evaluated this association in a larger case-control study, stratified by microsatellite instability phenotypes. Concordant with prior observations, gender (female) and smoking history were positively associated with colorectal cancers having an MSI-high phenotype.

MGMT immunohistochemical expression and promoter methylation in human glioblastoma.

O6-methylguanine-DNA methyltransferase (MGMT) expression has been recently proposed as a useful prognostic and/or predictive marker in glioblastoma patients receiving adjuvant therapy after the surgery. We studied samples from 50 patients with histologically confirmed GBM to evaluate MGMT expression by immunohistochemistry and its relation to promoter methylation status. Genomic DNA was extracted from scrapings of formalin-fixed, paraffin-embedded tissue corresponding to hematoxylin and eosin sections.

Frequency of defective DNA mismatch repair in colorectal cancer among the Alaska Native people.

The frequency of colorectal cancer (CRC) among the Alaska Native people is the highest of any ethnic group in the United States. In this study, CRC from 329 Alaska Native people (165 Eskimo, 111 Indians, and 53 Aleut) were evaluated for evidence of defective DNA mismatch repair (MMR) by testing tumors for altered protein expression (hMLH1, hMSH2, and hMSH6) and for the presence of microsatellite instability. Of the 329 samples tested, 46 (14%) showed both microsatellite instability and altered protein expression; 42 (91%) with a loss of hMLH1, 3 (7%) hMSH2, and 1 (2%) hMLH1/hMSH6.

Efficient isothermal amplification of the entire genome from single cells.

Preimplantation genetic diagnosis for single gene disorders is usually performed using polymerase chain reaction (PCR)-based methodologies modified for use in single cells. At present, single cell PCR tests require costly and time-consuming development and validation of highly sensitive amplification strategies to cover a growing number of mutations responsible for genetic disease. Whole-genome amplification (WGA) provides an opportunity to amplify the genome from a single blastomere to a level at which multiple tests can be performed on the same cell.