Role of the pathologist in the diagnosis of hereditary non-polyposis colorectal cancer

Issue title: LYNCH SYNDROME (HNPCC) AND MICROSATELLITE INSTABILITY

Article type: Research Article

Authors: Jass, Jeremy R.

Affiliations: McGill University, Montreal, Quebec, Canada

Note: [] Professor J.R. Jass, Department of Pathology, McGill University, Duff Medical Building, 3775 University Street, Montreal, Quebec, Canada H3A 2B4. Tel.: +1 514 398 7192; Fax: +1 514 398 7446; E-mail: [email protected]

Abstract: The aim of this paper is to indicate how the pathologist may suspect a diagnosis of hereditary non-polyposis colorectal cancer (HNPCC) on the basis of histological criteria and patient age alone. A single morphological feature, namely the presence of intra-epithelial lymphocytes (tumor infiltrating lymphocytes), identifies the majority of colorectal cancers (CRC) with the DNA microsatellite instability-high phenotype. A number of pathological criteria can help to distinguish HNPCC from sporadic MSI-H CRC, though age below 60 years is an important pointer towards HNPCC. Immunohistochemistry to demonstrate loss of expression of DNA mismatch repair genes serves as a highly reliable test of mismatch repair deficiency if antibodies to hMLH1, hMSH2, hMSH6 and hPMS2 are employed.

Keywords: HNPCC, pathology, diagnosis, tumor infiltrating lymphocytes

Journal: Disease Markers, vol. 20, no. 4-5, pp. 215-224, 2004