The growth of both MDA-MB231 cells, an oestrogen receptor (ER)-negative, EGFR-positive RAS transformed breast cancer cell line and HER18 cells, an ER-positive, HER-2/neu transfected MCF-7 breast cancer cell line, were both markedly inhibited by celecoxib in a xenograft model (Figure 2C; Barnes et al, 2003). This evidence concerns the gene ERBB2 and breast cancer.