title: Defective mismatch-repair colorectal cancer: clinicopathologic characteristics and usefulness of immunohistochemical analysis for diagnosis.
abstract: 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, paraffin-embedded surgical samples, and microsatellite analysis was performed by polymerase chain reaction with BAT-26. The results were correlated with immunohistochemical analysis for hMLH1 and hMSH2. Microsatellite instability (MSI) was detected in 13 (7.6%) tumors, and all showed loss of protein expression of hMLH1 (11/13) or hMSH2 (2/13) (P < .000). Patients with MMR-defective tumors more frequently had poorly differentiated tumors (5/13 [38%] vs 18/159 [11.3%]; P = .02) located in the ascending colon (8/13 [62%] vs 30/159 [18.9%]; P < .0001) and a personal history of other neoplasms (4/13 [31%] vs 18/159 [11.3%]; P = .05). There were no differences in age, family history of cancer, or TNM stage. Immunohistochemical analysis seems to be a reliable method to detect most colorectal cancers with defective MMR genes.
authors.affiliation: Department of Gastroenterology, General University Hospital of Alicante, Spain.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Jover
authors.forename: Artemio
authors.initials: A
authors.lastname: Payá
authors.forename: Cristina
authors.initials: C
authors.lastname: Alenda
authors.forename: María J
authors.initials: MJ
authors.lastname: Poveda
authors.forename: Gloria
authors.initials: G
authors.lastname: Peiró
authors.forename: F Ignacio
authors.initials: FI
authors.lastname: Aranda
authors.forename: Miguel
authors.initials: M
authors.lastname: Pérez-Mateo
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D000369:Aged, 80 and over; D020137:Base Pair Mismatch / Q000235:genetics*; D002352:Carrier Proteins; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology*; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D009367:Neoplasm Staging; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein