BRCA1 suppression in mammary epithelial cells (MECs) leads to an increase in epidermal growth factor receptor (EGFR) expression. (A) MECs were transfected with BRCA1 control or small interfering RNA 1 or 2 (si1, si2), or they were infected with lentivirus-expressing control or BRCA1-specific small hairpin RNA (sh1, sh2) and lysed for immunoblot analysis.. (B) The intensities of the chemiluminescence signals of EGFR, BRCA1 and tubulin levels were quantified using ImageJ software. (C) Flow cytometry using phycoerythrin-conjugated anti-EGFR antibodies shows an increase in cell surface EGFR expression after BRCA1 suppression (hMEC-hTERT; similar results were obtained with MCF-10A cells). (D) Immunofluorescence of EGFR in asynchronously growing HMLE (top) and after serum deprivation (bottom) in control (left) and BRCA1-suppressed MECs (right). Experiments were performed in triplicates using controls and two different small hairpin-containing MEC lines. (E) The fluorescence intensity of the images was quantified using ImageJ software.