If requested, an interpretive report will be provided All IHC stains will include a positive control tissue
Collection/ Processing Details:
Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an autosomal dominant hereditary cancer syndrome associated with germline mutations in the mismatch repair genes: MLH1, MSH2, MSH6, and PMS2
Patients with HNPCC have an increased risk of developing colorectal and endometrial cancer
Mutations of the PMS2 gene confer the lowest risk for any of the tumors within the HNPCC spectrum
Nuclear staining of internal control lymphocytes, and PMS2 intact tumor cells
Absence of staining for PMS2 in tumor nuclei indicates loss of protein expression for this marker
Used in a panel to identify patients at high risk for having hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome
IHC analysis is helpful for identifying the gene(s) responsible for the defective DNA mismatch repair within the tumor; the majority of MSI-H tumors show a loss of expression of at least 1 of the 4 mismatch repair genes
MSI-H phenotype or loss of protein expression by IHC within a tumor does not distinguish between somatic and germline mutations. Genetic testing of the gene indicated by IHC analysis can help to distinguish between these 2 possibilities.
Burgart LJ: Testing for defective DNA mismatch repair in colorectal carcinoma. A practical guide. Arch Pathol Lab Med 2005;129:1385-1389.