Defective Mismatch-Repair Colorectal Cancer

Heterogenous mismatch-repair status in colorectal cancer

BACKGROUND Immunohistochemical staining for mismatch repair proteins is efficient and widely used to identify mismatch repair defective tumors. The tumors typically show uniform and widespread loss of MMR protein staining. We identified and characterized colorectal cancers with alternative, heterogenous mismatch repair protein staining in order to delineate expression patterns and underlying me...

DNA mismatch repair genes and colorectal cancer.

Reduced COX-2 protein in colorectal cancer with defective mismatch repair.

Most colorectal adenomas and carcinomas arise in the setting of chromosomal instability characterized by progressive loss of heterozygosity. In contrast, approximately 15-20% of colorectal neoplasms arise through a distinct genetic pathway characterized by microsatellite instability (MSI) associated with frequent loss of expression of one of the DNA mismatch repair enzymes, most often hMLH1 or ...

Defective mismatch repair in extracts of colorectal and endometrial cancer cell lines exhibiting microsatellite instability.

A replication error (RER+) phenotype, characterized by somatic instability in simple repeated sequences, is associated with several types of cancer. To determine if a defect in DNA replication fidelity or repair of replication errors might explain this instability, we compared both processes in cell-free extracts from RER+ endometrial and colorectal cancer cell lines to RER- cell lines. SV40 or...

Anatomic Pathology / IMMUNOHISTOCHEMICAL ANALYSIS IN MMR-DEFECTIVE COLORECTAL CANCER Defective Mismatch-Repair Colorectal Cancer Clinicopathologic Characteristics and Usefulness of Immunohistochemical Analysis for Diagnosis

The purpose of our study was to determine the usefulness of immunohistochemical analysis for the diagnosis of mismatch-repair (MMR) gene defective colorectal tumors and to describe their prevalence and clinicopathologic characteristics. We studied 172 cases. DNA was extracted from formalin-fixed, paraffinembedded surgical samples, and microsatellite analysis was performed by polymerase chain re...