The upregulation of SRCs observed in the present study is in line with previous observations from a clinical trial on preoperative tamoxifen treatment in human breast cancer where tumors expressed significantly higher levels of especially SRC-3/AIB1, but also SRC-1 and SRC-2/TIF-2 mRNA compared to controls after 4 weeks of tamoxifen treatment [6]. This evidence concerns the gene SRC and breast cancer.