Genetic determinants and absence of breast cancer in Xavante Indians in Sangradouro Reserve, Brazil.

Genetic compositions of distinct human populations are different. How genomic variants influence many common and rare genetic diseases is always of great medical and anthropological interest, and understanding of genetic architectures of population groups in relation to diseases can advance our knowledge of medicine. Here, we have studied the genomic architecture of a group of Xavante Indians, an indigenous population in Brazil, and compared them with normal populations from the 1000 Genomes Projects.

SNPs/pools: a methodology for the identification of relevant SNPs in breast cancer epidemiology.

The identification of allelic variants of human genes is of great importance when assessing genetic susceptibility. The emerging role of genetic polymorphisms in association studies has created the need for high throughput genotyping methodologies that allow a more rapid identification of relevant polymorphisms related to individual cancer risk enabling the extension to large-scale association studies. DNA pooling methodology may be of great importance considering the cost, time and labor that are involved in large-scale genotyping analysis carried out on individual samples.

Breast cancer risk and polymorphisms in genes involved in metabolism of estrogens (CYP17, HSD17beta1, COMT and MnSOD): possible protective role of MnSOD gene polymorphism Val/Ala and Ala/Ala in women that never breast fed.

Polymorphisms in genes encoding enzymes involved in estrogen metabolism are held to be candidates for associations with breast disease, since there is evidence that circulating estrogens are associated with breast cancer risk. In this study, we evaluated the frequency of different polymorphisms related with estrogen metabolism [COMT Val158Met, CYP17 (5'UTR, T27C); HSD17beta1 Gly313Ser and MnSOD Val16Ala] in a breast cancer resistant population, the Xavante Indians, and the frequencies were compared with the ones reported in other populations where breast cancer case-control studies dealing with these polymorphisms have been carried out. The data obtained showed that, apart from the MnSOD Val16Ala polymorphism where the frequency of the variant allele was much higher than that reported in other populations, all the others were within the range reported in other populations.