title: Mutational targets in colorectal cancer cells with microsatellite instability.
abstract: Cancers arise from the sequential acquisition of genetic alterations in specific genes. The high number of mutations in cancer cells led to the hypothesis that an early step in tumor progression is the generation of a genetic instability. The potent role of genetic instability in initiation and progression of colorectal cancers has been well defined in hereditary nonpolyposis colon cancer (HNPCC) syndrome. HNPCC is a common hereditary disorder caused by germline mutations of DNA mismatch repair (MMR) genes. Somatic loss of the normal allele of the predisposition gene leads to a strong "mutator phenotype", characterized by a high rate of mutations in repetitive sequences. Nevertheless, the observation of frequent alterations of key growth regulatory genes in MMR-deficient cells such as NF1, APC, p53, K-Ras, with no significant excess of frameshift mutations and changes at short coding repeats, suggest that even in the presence of an inherited tendency to genomic instability, tumor progression is mainly driven by a process of natural selection.
authors.affiliation: Unité d'Oncologie Moléculaire and Unité INSERM U590, Centre Léon Bérard, 28 rue Laënnec, 69008, Lyon, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Bertholon
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Carlos Maria
authors.initials: CM
authors.lastname: Galmarini
authors.forename: Alain
authors.initials: A
authors.lastname: Puisieux
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D020137:Base Pair Mismatch / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics; D043171:Chromosomal Instability / Q000235:genetics; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000453:epidemiology / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D005602:France / Q000453:epidemiology; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D018095:Germ-Line Mutation; D006801:Humans; D015994:Incidence; D008297:Male; D018895:Microsatellite Repeats; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics; D009363:Neoplasm Proteins / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics; D011379:Prognosis; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein