title: Conventional and tissue microarray immunohistochemical expression analysis of mismatch repair in hereditary colorectal tumors.
abstract: Immunohistochemistry (IHC) of mismatch repair (MMR) proteins in colorectal tumors together with microsatellite analysis (MSI) can be helpful in identifying families eligible for mutation analysis. The aims were to determine sensitivity of IHC for MLH1, MSH2, and MSH6 and MSI analysis in tumors from known MMR gene mutation carriers; and to evaluate the use of tissue microarrays for IHC (IHC-TMA) of colon tumors in its ability to identify potential carriers of MMR gene mutations, and compare it with IHC on whole slides. IHC on whole slides was performed in colorectal tumors from 45 carriers of a germline mutation in one of the MMR genes. The TMA cohort consisted of 129 colon tumors from (suspected) hereditary nonpolyposis colorectal cancer (HNPCC) patients. Whole slide IHC analysis had a sensitivity of 89% in detecting MMR deficiency in carriers of a pathogenic MMR mutation. Sensitivity by MSI analysis was 93%. IHC can also be used to predict which gene is expected to harbor the mutation: for MLH1, MSH2, and MSH6, IHC on whole slides would have correctly predicted the mutation in 48%, 92%, and 75% of the cases, respectively. We propose a scheme for the diagnostic approach of families with (suspected) HNPCC. Comparison of the IHC results based on whole slides versus TMA, showed a concordance of 85%, 95%, and 75% for MLH, MSH2, and MSH6, respectively. This study therefore shows that IHC-TMA can be reliably used to simultaneously screen a large number of tumors from (suspected) HNPCC patients, at first in a research setting.
authors.affiliation: Center for Human and Clinical Genetics, Leiden, The Netherlands.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Hendriks
authors.forename: Patrick
authors.initials: P
authors.lastname: Franken
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: Dierssen
authors.forename: Wiljo
authors.initials: W
authors.lastname: De Leeuw
authors.forename: Juul
authors.initials: J
authors.lastname: Wijnen
authors.forename: Enno
authors.initials: E
authors.lastname: Dreef
authors.forename: Carli
authors.initials: C
authors.lastname: Tops
authors.forename: Martijn
authors.initials: M
authors.lastname: Breuning
authors.forename: Annette
authors.initials: A
authors.lastname: Bröcker-Vriends
authors.forename: Hans
authors.initials: H
authors.lastname: Vasen
authors.forename: Riccardo
authors.initials: R
authors.lastname: Fodde
authors.forename: Hans
authors.initials: H
authors.lastname: Morreau
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D020137:Base Pair Mismatch; D002352:Carrier Proteins; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics; D005091:Exons; D005260:Female; D006580:Genetic Carrier Screening; D018095:Germ-Line Mutation; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000235:genetics; D009687:Nuclear Proteins; D020411:Oligonucleotide Array Sequence Analysis; D011518:Proto-Oncogene Proteins / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein; 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