RESUMO
Previous studies have suggested that polymorphisms in CASP8 on chromosome 2 are associated with breast cancer risk. To clarify the role of CASP8 in breast cancer susceptibility, we carried out dense genotyping of this region in the Breast Cancer Association Consortium (BCAC). Single-nucleotide polymorphisms (SNPs) spanning a 1 Mb region around CASP8 were genotyped in 46 450 breast cancer cases and 42 600 controls of European origin from 41 studies participating in the BCAC as part of a custom genotyping array experiment (iCOGS). Missing genotypes and SNPs were imputed and, after quality exclusions, 501 typed and 1232 imputed SNPs were included in logistic regression models adjusting for study and ancestry principal components. The SNPs retained in the final model were investigated further in data from nine genome-wide association studies (GWAS) comprising in total 10 052 case and 12 575 control subjects. The most significant association signal observed in European subjects was for the imputed intronic SNP rs1830298 in ALS2CR12 (telomeric to CASP8), with per allele odds ratio and 95% confidence interval [OR (95% confidence interval, CI)] for the minor allele of 1.05 (1.03-1.07), P = 1 × 10(-5). Three additional independent signals from intronic SNPs were identified, in CASP8 (rs36043647), ALS2CR11 (rs59278883) and CFLAR (rs7558475). The association with rs1830298 was replicated in the imputed results from the combined GWAS (P = 3 × 10(-6)), yielding a combined OR (95% CI) of 1.06 (1.04-1.08), P = 1 × 10(-9). Analyses of gene expression associations in peripheral blood and normal breast tissue indicate that CASP8 might be the target gene, suggesting a mechanism involving apoptosis.
Assuntos
Neoplasias da Mama/genética , Caspase 8/genética , Cromossomos Humanos Par 2/genética , Proteínas/genética , População Branca/genética , Neoplasias da Mama/etnologia , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/genética , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Técnicas de Genotipagem , Humanos , Polimorfismo de Nucleotídeo ÚnicoRESUMO
A 1.5-cm nonpalpable mass was detected in the upper outer quadrant of the left breast by screening mammography in a 55-year-old woman. The patient was scheduled for a sentinel node procedure, and lymphoscintigraphy was performed the day before surgery. Unintentionally, she received an intraparenchymal tracer injection 3 cm away from the malignant lesion instead of the intended intratumoral injection. Lymphoscintigraphy revealed two sentinel nodes in the axilla. A second dose of Tc-99m nanocolloid was injected the next day into the primary tumor through a catheter that had been inserted under ultrasound guidance the previous day. Once more, a lymphoscintigraphic image was obtained that showed additional sentinel nodes in two different regions outside the axilla. This observation supports the authors' contention that lymphatic watersheds exist in the breast and highlights the importance of tracer administration into or close to the tumor.
Assuntos
Neoplasias da Mama/diagnóstico por imagem , Linfonodos/diagnóstico por imagem , Biópsia de Linfonodo Sentinela/métodos , Agregado de Albumina Marcado com Tecnécio Tc 99m/administração & dosagem , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico por imagem , Carcinoma Ductal de Mama/secundário , Extravasamento de Materiais Terapêuticos e Diagnósticos/prevenção & controle , Feminino , Humanos , Achados Incidentais , Injeções Intralesionais/métodos , Injeções Subcutâneas/métodos , Linfonodos/patologia , Metástase Linfática , Pessoa de Meia-Idade , Palpação , Cintilografia , Compostos Radiofarmacêuticos/administração & dosagem , Compostos Radiofarmacêuticos/farmacocinética , Agregado de Albumina Marcado com Tecnécio Tc 99m/farmacocinéticaRESUMO
GWAS have identified a breast cancer susceptibility locus on 2q35. Here we report the fine mapping of this locus using data from 101,943 subjects from 50 case-control studies. We genotype 276 SNPs using the 'iCOGS' genotyping array and impute genotypes for a further 1,284 using 1000 Genomes Project data. All but two, strongly correlated SNPs (rs4442975 G/T and rs6721996 G/A) are excluded as candidate causal variants at odds against >100:1. The best functional candidate, rs4442975, is associated with oestrogen receptor positive (ER+) disease with an odds ratio (OR) in Europeans of 0.85 (95% confidence interval=0.84-0.87; P=1.7 × 10(-43)) per t-allele. This SNP flanks a transcriptional enhancer that physically interacts with the promoter of IGFBP5 (encoding insulin-like growth factor-binding protein 5) and displays allele-specific gene expression, FOXA1 binding and chromatin looping. Evidence suggests that the g-allele confers increased breast cancer susceptibility through relative downregulation of IGFBP5, a gene with known roles in breast cell biology.