RESUMO
BACKGROUND: Activating mutations in the KRAS gene occur frequently in human tumors, including colorectal carcinomas; most mutations occur in codons 12 and 13. Mutations in KRAS have been associated with poor response to anti-epidermal growth factor receptor antibodies. Therefore, an accurate and readily available analysis of KRAS mutational status is needed. The aim of this study was to evaluate concordance between KRAS assays performed by 6 different laboratories. METHODS: Forty formalin-fixed paraffin-embedded colorectal cancer tumor samples were obtained. Sample sections were submitted for KRAS mutation analysis to 5 independent commercial laboratories (Agencourt, Gentris, Genzyme, HistoGeneX, and Invitek) and to the Amgen DNA Sequencing Laboratory for direct polymerase chain reaction sequencing. The assay used by Invitek is no longer commercially available and has been replaced by an alternative technique. Results from the commercial services were compared with those from Amgen direct sequencing by kappa statistics. RESULTS: KRAS mutations were observed in codon 12 and/or 13 in 20 of 40 (50%) samples in Amgen direct sequencing assays. Results from HistoGeneX (kappa = 0.95), Genzyme (kappa = 0.94), and Agencourt (kappa = 0.94) were in almost perfect agreement with these results, and the results from Gentris were in substantial agreement with the results from Amgen (kappa = 0.75). The Invitek allele-specific assay demonstrated slight agreement (kappa = 0.13). CONCLUSIONS: This study provides data on the comparability of KRAS mutational analyses. The results suggest that most (but not all) commercial services provide analysis that is accurate and comparable with direct sequencing.
Assuntos
Adenocarcinoma/genética , Carcinoma/genética , Neoplasias Colorretais/genética , Análise Mutacional de DNA , Mutação , Proteínas Proto-Oncogênicas/genética , Kit de Reagentes para Diagnóstico , Proteínas ras/genética , Adenocarcinoma/patologia , Adenocarcinoma/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma/patologia , Carcinoma/terapia , Códon , Neoplasias Colorretais/patologia , Neoplasias Colorretais/terapia , Feminino , Fixadores , Formaldeído , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Inclusão em Parafina , Reação em Cadeia da Polimerase , Valor Preditivo dos Testes , Proteínas Proto-Oncogênicas p21(ras) , Reprodutibilidade dos Testes , Fixação de TecidosRESUMO
A phase I gene transfer clinical study was undertaken to examine the ability to introduce a potential anti-human immunodeficiency virus (HIV) gene therapeutic into hematopoietic progenitor cells (HPC), thereby contributing to multilineage engraftment. The potential therapeutic effect of genetically modifying HPC with protective genes in HIV-infected adults depends in part on the presence of adult thymic activity and myeloid capacity in the setting of HIV replication. Herein we report the presence and expression of a retroviral vector encoding an anti-HIV-1 ribozyme in mature hematopoietic cells of different lineages, and de novo T-lymphocyte development ensuing from genetically engineered CD34(+) HPC. Sustained output of vector-containing mature myeloid and T-lymphoid cells was detected even in patients with multidrug-resistant infection. In addition, the study showed that the degree of persistence of gene-containing cells was dependent on transduced HPC dose. These novel findings support the concept of gene therapy as a modality to effect immune reconstitution with cells engineered to inhibit HIV replication and this report represents the first demonstration of long-term maintenance of a potential therapeutic transgene in HIV disease.