• All IHC stains will include a positive control tissue

• 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.

Submit a formalin-fixed, paraffin embedded tissue block

Formalin-fixed, paraffin embedded (FFPE) tissue block

FFPE tissue section mounted on a charged, unstained slide

Ambient (preferred)

• Unlabeled/mislabeled block
• Insufficient tissue
• Slides broken beyond repair

Immunohistochemical staining and microscopic examination

If requested, an interpretive report will be provided

Specifications

• 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

Staining pattern

• Nuclear staining of internal control lymphocytes, and MSH2 intact tumor cells
• Absence of staining for MSH2 in tumor nuclei indicates loss of protein expression for this marker

References

1. Burgart LJ: Testing for defective DNA mismatch repair in colorectal carcinoma. A practical guide. Arch Pathol Lab Med 2005;129:1385-138