BRCA1 inhibition increases EGFR expression in the aldehyde dehydrogenase 1 (ALDH1)-negative and -positive MEC fractions. Cells were (A, B and C) transfected with either control or BRCA1 small interfering RNA (siRNA) or (D, E and F) infected with lentiviruses expressing control or BRCA1 small hairpin RNA (shRNA). Cells treated with the ALDH1 inhibitor diethylaminobenzaldehyde (DMEA) served as controls (A and D). (G and H) BRCA1 inhibition increases the expression of cell surface-bound EGFR in human MEC-human telomerase reverse transcriptase (hMEC-hTERT) or MCF-10A cells in the ALDH1-negative and the ALDH1-positive fractions. Live cells were harvested and incubated with ALDH1 reagent followed by immunostaining with phycoerythrin (PE)-conjugated anti-EGFR antibodies and quantification of EGFR using the QuantiBrite standards for PE.