The Significance of Erythropoietin Receptor (EpoR) Acquisition by Breast Cancer Cells

Data from our lab and others indicate that normal breast cells do not express the erythropoietin receptor EpoR conversely breast cancer Ca Br cells express functional EpoR. Expression of EpoR appears greatest in poorly oxygenated tumor regions and in patients with negative estrogen receptor status a sign of more aggressive disease. Additionally one study demonstrated that the EpoR gene is overexpressed in patients with micrometastatic disease. The differential expression of EpoR between normal and cancerous breast cells has led us to hypothesize that acquisition of EpoR expression bv mammary epithelial cells may be part of malignant transformation and may impact disease progression and metastasis. Our data demonstrating changes in mammary epithelial cell biology associated with acquisition of EpoR expression support this hypothesis and suggest that EpoR acquisition results in mammary epithelial cell with a premalignant phenotype. These data will help us better understand the oncogenic process in CaBr and may suggest the need for caution in administering Epo to at least some CaBr patients.