Parkinson's disease genes do not segregate with breast cancer genes' loci.

BACKGROUND Breast cancer and skin cancer rates among patients with Parkinson's disease are higher than in non-Parkinson's disease cases, and Jewish-Ashkenazi LRRK2*G2019S mutation carriers have higher breast cancer rates than noncarriers. Because additional Parkinson's disease predisposition genes are implicated in the malignant transformation process, we hypothesized that the association between breast cancer and Parkinson's disease may be related to segregation of breast cancer loci with known Parkinson's disease predisposition loci. METHODS Data mining for single-nucleotide polymorphisms (SNP), reportedly associated with breast cancer in genome-wide association study (GWAS) that localize to chromosomes bearing known Parkinson's disease predisposition loci: PARK7, PINK1 (chromosome 1); SNCA (chromosome 4); PARK2 (chromosome 6); and LRRK2 (chromosome 12), was carried out. RESULTS A total of 188 breast cancer-associated SNPs were identified in 29 eligible manuscripts: 43 SNPs on chromosome 1 (PINK1), 46 SNPs on chromosome 4 (SNCA), 72 SNPs on chromosome 6 (PARK2), and 27 SNPs on chromosome 12 (LRRK2). No breast cancer-associated SNP was located at distance less than 500,000 bp from any of the analyzed Parkinson's disease predisposition genes. CONCLUSIONS The association between breast cancer and the most common genetic-inherited forms of Parkinson's disease cannot be accounted for by allele cosegregation at the genomic level. IMPACT To elucidate the association between Parkinson's disease and breast cancer, a comprehensive approach that spans beyond a simple genetic association is required.