For breast cancer data, we map highly expressed genes from TCGA dataset onto SNPs from GWAS, we focus on the genes BRCA1 and BRCA2, as germline mutations in those genes are the main part of genetic and hereditary factors for breast cancer [49]; we finally extract only regions having at least one overlapping SNP taken from GWAS studies mapped to the same trait. The gene discussed is BRCA1; the disease is breast cancer.