title: Role of the pathologist in the diagnosis of hereditary non-polyposis colorectal cancer.
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.
authors.affiliation: McGill University, Montreal, Quebec, Canada. jeremy.jass@mcgill.ca
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Jass
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D020137:Base Pair Mismatch; D014408:Biomarkers, Tumor; D018276:Carcinoma, Medullary / Q000473:pathology; D002352:Carrier Proteins; D002454:Cell Differentiation; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D004260:DNA Repair; D043243:DNA Sequence, Unstable; D005838:Genotype; D006801:Humans; D007150:Immunohistochemistry; D016246:Lymphocytes, Tumor-Infiltrating / Q000166:cytology / Q000378:metabolism; D018895:Microsatellite Repeats; D000070957:MutL Protein Homolog 1; D009154:Mutation; D009363:Neoplasm Proteins / Q000378:metabolism; D009687:Nuclear Proteins; D010336:Pathology / Q000379:methods*; D010641:Phenotype
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D002352:Carrier Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1