Differential gene expression in human mammary carcinoma cells: identification of a new member of a receptor family.

Differential gene expression in mammary carcinoma cell lines MCF-7 and MCF-7ADR was investigated by Differential Display Technique. These two cell lines represent a model system for progression of mammary carcinoma: MCF-7 is estradiol-dependent for growth, estrogen-receptor positive, tamoxifen responsive, vimentin negative, Adriamycin sensitive and not invasive in vitro or in vivo while MCF-7ADR is estradiol-independent for growth, estrogen-receptor negative, tamoxifen resistant, vimentin positive, Adriamycin resistant and invasive in vitro and in vivo. Here we describe the identification of a new receptor expressed exclusively in MCF-7ADR. The receptor covers 157 amino acids with a predicted topology of four transmembrane and two extracellular domains. Additional members of the gene family are: peripheral membrane protein PMP22, epithelial membrane protein EMP-1 and squamous cell differentiation marker CL-20.