To further unravel the mechanisms by which the SNPs in intron 2 of FGFR2 increase breast cancer risk, and to address the heterogeneous cellular composition of breast tumors, we studied the expression of FGFR2 mRNA in relation to the rs2981578 genotype in fibroblasts and epithelial cells cultured from breast tissue. The gene discussed is FGFR2; the disease is breast carcinoma.