The present study was, thus, undertaken to: 1) investigate the mRNA expression of UGTs involved in estrogen metabolism; 2) compare UGT1A1 mRNA expression to potential clinical relevance (i.e. associations with tumor stage), ethnicity, and menopausal status in a group of human breast tumors and non-tumor (normal) breast tissues, and 3) investigate the association between variations in the number of TA repeats in the promoter region of UGT1A1 with gene expression. The gene discussed is UGT1A1; the disease is neoplasm.