As per an international consortium of researchers, the risk of breast cancer, in those who are carriers of BRCA1 breast cancer gene and those who are non-carriers, depend on the presence and absence of specific non-BRCA1 mutations.
A genome-wide study was done in as many as 8,300 BRCA1 carriers and five single nucleotide polymorphisms (SNPs) in one chromosomal region was found, that was responsible for distinguishing BRCA1 carriers who developed cancer from those carriers who were cancer free.
The five SNPs were found to be present on the same locus on chromosome 19p13. The scientists are hopeful that this discovery will help in determining histologic subtype of breast cancer that is present in BRCA1 carriers and non-carriers.
The scientists have also found out new genetic variants that are linked to ovarian cancer. They analysed the DNA of as many as 10,000 women, who were suffering from ovarian cancer. The DNA sample of 13,000 women without the disease was also analysed. The researchers managed to identify five genetic variants in chromosomes 2, 3, 8, 17, and 19 that were linked with ovarian cancer risk.
Out of five, four variants were present in those women who were suffering from serous ovarian cancer, which is considered as the most common and aggressive form of the disease.
The study report has been published in the September 19 issue of the journal Nature Genetics.