We revealed that BC5 carcinoma cells were PGRlow/ERbhigh/ERa−/Cyp19+, the BrCCh1 cells that originated from the recurrent tumour were PGR−/ERb+/ERa−/Cyp19+, and normal BN cells were PGR−/ERb+/ERa−/Cyp19high. This evidence concerns the gene CYP19A1 and carcinoma.