BRCA1 and breast cancer: Moreover, high levels of RANK expression were observed in breast cancer samples from premalignant lesions and patients with BRCA1 mutations (89, 90); SNP data analysis from the Cooperative Tumor Gene-Environmental Research (iCOGS), including approximately 15,200 BRCA1 and 8,200 BRCA2 mutation carriers, identified 6 SNPs which were significantly associated with breast cancer risk at the TNFRSF11A locus (encoding RANK) (90).