1. Diagnosis of Constitutional Mismatch Repair-deficiency Syndrome Based on Microsatellite Instability and Lymphocyte Tolerance to Methylating Agents
- Author
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Bodo, S., Colas, C., Buhard, O., Collura, A., Tinat, J., Lavoine, N., Guilloux, A., Chalastanis, A., Lafitte, P., Coulet, F., Buisine, M.P., Ilencikova, D., Ruiz-Ponte, C., Kinzel, M., Grandjouan, S., Brems, H.I., Lejeune, S., Blanche, H., Wang, Q., Caron, O., Cabaret, O., Syrcek, M.L., Vidaud, D., Parfait, B., Verloes, A., Knappe, U.J., Soubrier, F., Mortemousque, I., Leis, A., Auclair-Perrossier, J., Frebourg, T., Flejou, J.F., Entz-Werle, N., Leclerc, J., Malka, D., Cohen-Haguenauer, O., Goldberg, Y., Gerdes, A.M., Fedhila, F., Mathieu-Dramard, M., Lin, R.H., Wafaa, B., Gauthier-Villars, M., Bourdeaut, F., Sheridan, E., Vasen, H., Brugieres, L., Wimmer, K., Muleris, M., Duva, A., and European Consortium Care CMMRD
- Subjects
Male ,Heredity ,DNA Mutational Analysis ,Predisposition ,Bioinformatics ,PMS2 ,Lymphocytes ,Mismatch Repair Endonuclease PMS2 ,Adenosine Triphosphatases ,Tumor ,Colon Cancer ,Brain Neoplasms ,Gastroenterology ,Nuclear Proteins ,Lynch syndrome ,DNA-Binding Proteins ,MutS Homolog 2 Protein ,Phenotype ,DNA mismatch repair ,Female ,Microsatellite Instability ,Colorectal Neoplasms ,MutL Protein Homolog 1 ,Adult ,congenital, hereditary, and neonatal diseases and abnormalities ,Biology ,MLH1 ,Transfection ,Methylation ,Young Adult ,Germline mutation ,Neoplastic Syndromes, Hereditary ,Predictive Value of Tests ,medicine ,Biomarkers, Tumor ,Humans ,Genetic Predisposition to Disease ,Genetic Testing ,Antineoplastic Agents, Alkylating ,Germ-Line Mutation ,Adaptor Proteins, Signal Transducing ,Hepatology ,Microsatellite instability ,Reproducibility of Results ,medicine.disease ,Functional Tests ,HCT116 Cells ,Colorectal Neoplasms, Hereditary Nonpolyposis ,digestive system diseases ,MSH6 ,DNA Repair Enzymes ,MSH2 ,Drug Resistance, Neoplasm ,Case-Control Studies ,Cancer research ,Caco-2 Cells ,Multiplex Polymerase Chain Reaction - Abstract
Background & Aims Patients with bi-allelic germline mutations in mismatch repair (MMR) genes ( MLH1 , MSH2 , MSH6 , or PMS2 ) develop a rare but severe variant of Lynch syndrome called constitutional MMR deficiency (CMMRD). This syndrome is characterized by early-onset colorectal cancers, lymphomas or leukemias, and brain tumors. There is no satisfactory method for diagnosis of CMMRD because screens for mutations in MMR genes are noninformative for 30% of patients. MMR-deficient cancer cells are resistant to genotoxic agents and have microsatellite instability (MSI), due to accumulation of errors in repetitive DNA sequences. We investigated whether these features could be used to identify patients with CMMRD. Methods We examined MSI by PCR analysis and tolerance to methylating or thiopurine agents (functional characteristics of MMR-deficient tumor cells) in lymphoblastoid cells (LCs) from 3 patients with CMMRD and 5 individuals with MMR-proficient LCs (controls). Using these assays, we defined experimental parameters that allowed discrimination of a series of 14 patients with CMMRD from 52 controls (training set). We then used the same parameters to assess 23 patients with clinical but not genetic features of CMMRD. Results In the training set, we identified parameters, based on MSI and LC tolerance to methylation, that detected patients with CMMRD vs controls with 100% sensitivity and 100% specificity. Among 23 patients suspected of having CMMRD, 6 had MSI and LC tolerance to methylation (CMMRD highly probable), 15 had neither MSI nor LC tolerance to methylation (unlikely to have CMMRD), and 2 were considered doubtful for CMMRD based on having only 1 of the 2 features. Conclusion The presence of MSI and tolerance to methylation in LCs identified patients with CMMRD with 100% sensitivity and specificity. These features could be used in diagnosis of patients.
- Published
- 2015