March 30 (HealthDay News) -- U.S. researchers say they've spotted new gene variations that could boost the risk of sporadic breast cancer.
The same team also confirmed previously identified associations between certain regions in the human genome and breast cancer risk.
The newly identified genetic variations are located on chromosomes 1 and 14. The region on chromosome 1 contained the rs11249433 single nucleotide polymorphism (SNP). SNPs, the most common type of genetic variation, affect just a single building block of DNA.
The function of the rs11249433 SNP is unknown, but the region on chromosome 1 where it's located is predominately associated with estrogen receptor-positive breast cancer, the most common molecular type of breast cancer, the researchers said.
The region identified on chromosome 14 includes the rs999737 SNP, which is located near a gene called RAD51L1, which is a pathway implicated in breast cancer.
The Cancer Genetic Markers of Susceptibility (CGEMS) team also confirmed previous studies that found that six other genomic regions -- located on chromosomes 2, 5, 8, 10 and 16 -- are associated with breast cancer. Further study of all these regions may help improve understanding of what causes breast cancer.
"By studying large populations of individuals with and without disease, CGEMS research can provide powerful indicators as to which SNP variations are associated with breast cancer," Dr. Stephen Chanock, director of the U.S. National Cancer Institute's Core Genotyping Facility and chief of the Laboratory of Translational Genomics in the Division of Cancer Epidemiology and Genetics, said in an NCI news release.
"The two new regions identified in our study open up great possibilities for research into novel pathways contributing to the development of breast cancer. In turn, an in-depth understanding of the biology underlying the contribution of these genetic variations could one day lead to new approaches for therapy or prevention of breast cancer," he said.
The study was published online March 29 in the journal Nature Genetics.
SOURCE: U.S. National Cancer Institute, news release, March 29, 2009