RESUMEN
Lung cancer (LC) is a leading cause of cancer-related mortality. Although smoking is the major risk factor, ~15% of all cases occur in never-smokers, suggesting that genetic factors play a role in LC predisposition. Indeed, germline mutations in the TP53 gene predispose to multiple cancer types, including LC. To date, few studies compared the somatic and germline mutational profiles of LC cases by smoking status, and none was reported in Brazilians. Whole-exome sequencing (WES) was performed on two pools (seven smokers and six non-smokers) of tumor-derived DNA using the Illumina HiSeq2000 platform. Files from pools were analyzed separately using Ingenuity®Variant AnalysisTM and Mendel,MD. Validation of all candidate variants was performed by Sanger sequencing. Subsequently, validated mutations were analyzed in germline DNA from the same patients and in ethnically matched controls. In addition, a single recurring Brazilian TP53 germline mutation (R337H) was genotyped in 45 non-small-cell lung cancer patients.Four novel germline variants in the ATAD2, AURKA, PTPRD and THBS1 genes were identified exclusively in smoker patients, and four germline missense variants in PLCD1, RAD52, CP and CDC6 genes were identified solely in non-smokers. There were 4/45 (8.9%) germline carriers of the R337H TP53 mutation. In conclusion, the recurring Brazilian TP53 mutation should be genotyped in all non-small-cell lung cancer in Brazil, regardless of smoking status. Distinct pathogenic mutations and novel sequence variants are detected in Brazilian non-small-cell lung cancer patients, by smoking status. The contribution of these sequence variants to LC pathogenesis remains to be further explored.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/genética , Mutación de Línea Germinal/genética , Neoplasias Pulmonares/genética , Fumar/genética , Adulto , Anciano , Brasil , Femenino , Predisposición Genética a la Enfermedad/genética , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/genética , Proteína p53 Supresora de Tumor/genéticaRESUMEN
Familial isolated pituitary adenoma (FIPA) is a rare genetic disorder. In a subset of FIPA families AIP germline mutations have been reported, but in most FIPA cases the exact genetic defect remains unknown. The present study aimed to determine the genetic basis of FIPA in a Brazilian family. Three siblings presented with isolated prolactin genes. Further mutation screening was performed using whole-exome sequencing and all likely causative mutations were validated by Sanger sequencing. In silico analysis and secreting pituitary adenoma diagnosed through clinical, biochemical and imaging testing. Sanger sequencing was used to genotype candidate prolactinoma-mutated additional predictive algorithms were applied to prioritize likely pathogenic variants. No mutations in the coding and flanking intronic regions in the MEN1, AIP and PRLR genes were detected. Whole-exome sequencing of three affected siblings revealed novel, predicted damaging, heterozygous variants in three different genes: RXRG, REXO4 and TH. In conclusion, the RXRG and TH possibly pathogenic variants may be associated with isolated prolactinoma in the studied family. The possible contribution of these genes to additional FIPA families should be explored.
Asunto(s)
Adenoma/genética , Mutación de Línea Germinal , Adenoma Hipofisario Secretor de Hormona del Crecimiento/genética , Prolactinoma/genética , Receptor gamma X Retinoide/genética , Tirosina 3-Monooxigenasa/genética , Adulto , Simulación por Computador , Análisis Mutacional de ADN , Exoma , Femenino , Predisposición Genética a la Enfermedad , Humanos , Péptidos y Proteínas de Señalización Intracelular/química , Péptidos y Proteínas de Señalización Intracelular/genética , Masculino , Linaje , Proteínas Proto-Oncogénicas/química , Proteínas Proto-Oncogénicas/genética , Receptores de Prolactina/química , Receptores de Prolactina/genética , Receptor gamma X Retinoide/química , Tirosina 3-Monooxigenasa/químicaRESUMEN
Lung cancer is the leading global cause of cancer-related mortality. Inter-individual variability in treatment response and prognosis has been associated with genetic polymorphisms in specific genes: EGFR, KRAS, BRAF, PTEN and TTF-1. Somatic mutations in EGFR and KRAS genes are reported at rates of 15-40% in non-small cell lung cancer (NSCLC) in ethnically diverse populations. BRAF and PTEN are commonly mutated genes in various cancer types, including NSCLC, with PTEN mutations exerting an effect on the therapeutic response of EGFR/AKT/PI3K pathway inhibitors. TTF-1 is expressed in approximately 80% of lung adenocarcinomas and its positivity correlates with higher prevalence of EGFR mutation in this cancer type. To determine molecular markers for lung cancer in Brazilian patients, the rate of the predominant EGFR, KRAS, BRAF and PTEN mutations, as well as TTF-1 expression, was assessed in 88 Brazilian NSCLC patients. EGFR exon 19 deletions (del746-750) were detected in 3/88 (3·4%) patients. Activating KRAS mutations in codons 12 and 61 were noted in five (5·7%) and two (2·3%) patients, respectively. None of the common somatic mutations were detected in either the BRAF or PTEN genes. TTF-1 was overexpressed in 40·7% of squamous-cell carcinoma (SCC). Our findings add to a growing body of data that highlights the genetic heterogeneity of the abnormal EGFR pathway in lung cancer among ethnically diverse populations.