RESUMO
BACKGROUND: Latin American and Hispanic women are less likely to develop breast cancer (BC) than women of European descent. Observational studies have found an inverse relationship between the individual proportion of Native American ancestry and BC risk. Here, we use ancestry-informative markers to rule out potential confounding of this relationship, estimating the confounder-free effect of Native American ancestry on BC risk. METHODS AND STUDY POPULATION: We used the informativeness for assignment measure to select robust instrumental variables for the individual proportion of Native American ancestry. We then conducted separate Mendelian randomization (MR) analyses based on 1401 Colombian women, most of them from the central Andean regions of Cundinamarca and Huila, and 1366 Mexican women from Mexico City, Monterrey and Veracruz, supplemented by sensitivity and stratified analyses. RESULTS: The proportion of Colombian Native American ancestry showed a putatively causal protective effect on BC risk (inverse variance-weighted odds ratio [OR] = 0.974 per 1% increase in ancestry proportion, 95% confidence interval [CI] 0.970-0.978, p = 3.1 × 10-40). The corresponding OR for Mexican Native American ancestry was 0.988 (95% CI 0.987-0.990, p = 1.4 × 10-44). Stratified analyses revealed a stronger association between Native American ancestry and familial BC (Colombian women: OR = 0.958, 95% CI 0.952-0.964; Mexican women: OR = 0.973, 95% CI 0.969-0.978), and stronger protective effects on oestrogen receptor (ER)-positive BC than on ER-negative and triple-negative BC. CONCLUSIONS: The present results point to an unconfounded protective effect of Native American ancestry on BC risk in both Colombian and Mexican women which appears to be stronger for familial and ER-positive BC. These findings provide a rationale for personalised prevention programmes that take genetic ancestry into account, as well as for future admixture mapping studies.
Assuntos
Indígena Americano ou Nativo do Alasca , Neoplasias da Mama , Feminino , Humanos , Indígena Americano ou Nativo do Alasca/etnologia , Indígena Americano ou Nativo do Alasca/genética , Indígena Americano ou Nativo do Alasca/estatística & dados numéricos , Mama , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/etnologia , Neoplasias da Mama/genética , Colômbia/epidemiologia , México/epidemiologia , Neoplasias de Mama Triplo Negativas/epidemiologia , Neoplasias de Mama Triplo Negativas/etnologia , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
BACKGROUND: Genetic variants in microRNA (miR) binding sites affect the regulation of miR-dependent gene expression and have been linked to the risk of a variety of cancers including breast cancer (BC). Most BC risk variants had been identified in women of European and Asian ancestry, but genetic data for Hispanic women are scarce. Here, we investigate the association between six variants in miR binding sites and BC risk in Colombian women. METHODS: We genotyped miR binding site variants in the BMPR1B, TGFBR1, IQGAP1, KRAS, SETD8 and RYR3 genes in 1022 BC cases and 1023 controls from the Colombian breast cancer case-control (Col-BCCC) study using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Multiple logistic regression and permutation techniques were applied to assess the association between genetic variants and BC risk. RESULTS: We found no evidence of association between any of the six miR binding site variants and overall or estrogen receptor subtype-specific BC risk in Colombian women. CONCLUSION: Our findings may point to ethnic differences in the association between genetic variability in miR binding sites and breast cancer risk.
RESUMO
Latino women show lower incidences of breast cancer (BC) than non-Hispanic whites. Large-scale genetic association studies have identified variants robustly associated with BC risk in European women. We examine here the relevance of these variants to Colombian BC and possible interactions with genetic ancestry. Native American, European and African proportions were estimated for 1022 Colombian BC cases and 1023 controls. Logistic regression was applied to assess the association between 78 variants and BC risk and interactions between the variants and ancestry proportions. We constructed a multifactorial risk score combining established BC risk factors, associated risk variants and individual ancestry proportions. Each 1% increase in the Native American proportion translated into a 2.2% lower BC risk (95% CI: 1.4-2.9). Thirteen variants were associated with BC in Colombian women, with allele frequencies and risk effects partially different from European women. Ancestry proportions moderated the risk effects of two variants. The ability of Native American proportions to separate Colombian cases and controls (area-under-the-curve (AUC) = 0.61) was similar to the discriminative ability of family history of BC in first-degree female relatives (AUC = 0.58) or the combined effect of all 13 associated risk variants (AUC = 0.57). Our findings demonstrate ample potential for individualized BC prevention in Hispanic women taking advantage of individual Native American proportions, information on established susceptibility factors and recently identified common risk variants.
Assuntos
Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla/métodos , Estudos de Casos e Controles , Colômbia/epidemiologia , Feminino , Frequência do Gene/genética , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único/genética , RiscoRESUMO
Abordagem prática, para a implementação de um sistema de gerenciamento ambiental que suprisse as exigências da BS7750, e da EMAS, e eventualmente da ISO 14000. Não trata do conteúdo das normas ou da Regulamentação, apesar de referir-se a elas, mas fornece uma rota para atingir as metas do cumprimento