We compared the expression profile of the six miRNAs observed in paired tissue and sera of different subtype of breast cancer with the respective breast cancer cell lines MCF-7 (ER+PR+EGFR-) and MDA-MB-231 (ER-PR-EGFR-) including normal breast epithelial cell lines MCF-10A to examine if results from fresh tumor tissue and serum can be comparable with that of the cell lines propagated for a long time in in-vitro culture (Fig 2D and Table 3). The gene discussed is ESR1; the disease is breast cancer.