The functions of GRPs suggest that they may also play important roles in cancer biology and in the last years knowledge about the association of GRPs and cancer has increased: studies of GRPs have been performed with cells in culture [3-7] and only a few studies were conducted with human cancers, recently for breast cancer [8,9], prostate cancer [10] or lung cancer for GRP78[11] and for lung [12], colorectal [13] and esophageal squamous cell carcinoma for GRP94 [14]. The gene discussed is HSP90B1; the disease is breast carcinoma.