The cell lines were chosen on the basis of their ER, PR and HER2/neu receptor status and the expression of miR-183 in breast cancer cell lines mirrored that of the clinical breast tumor samples, with the lowest expression in T47D cells which are ER+ve/PR+ve and HER2/neu -ve, and the highest expression in SKBR-3 cells which are ER-ve/PR-ve and HER2/neu +ve (figure 2). The gene discussed is ESR1; the disease is breast carcinoma.