A cDNA microarray comparison between the ER-positive MCF-7 breast cancer cell line and its tamoxifen-selected, ER-negative derivative, TMX2-28, had shown that paralemmin-1 mRNA was more highly expressed (8 times greater) in TMX2-28 cells than in MCF-7 cells[5]. The gene discussed is ESR1; the disease is breast carcinoma.