The Breast Cancer Association Consortium brought together data from more than 20 groups conducting breast cancer research. Numerous studies by the collaboration's groups have identified a number of single nucleotide polymorphisms' single variations in a gene, known as SNPs, that may be linked to breast cancer.
The collaborating groups identified 16 SNPs that had been analyzed by at least three of their studies. They pooled data from all studies for each SNP and assessed how frequently the genetic change occurred in breast cancer patients compared to controls.
The authors found that five of the SNPs might be linked to breast cancer risk (with borderline statistical significance) and 11 were not. They suggest that pooling data from many groups can enable large sample sizes necessary to see associations when effects are moderate.
"This study illustrates the value of large consortia for clarifying risks associated with complex diseases," the authors write.
In an accompanying editorial, John P.A. Ioannidis, M.D., of the University of Ioannina School of Medicine in Greece, calls the study an "impressive collaborative effort." He discusses the difficulty of designing studies to accurately assess the significance of rare genetic changes. He writes, "If common genetic variants modulate susceptibility to common diseases such as breast cancer, we now have excellent tools to dissect them."