The MAPK/ERK1/2 pathway can also be rapidly activated by estrogens in various cell types, such as endothelial (Chen et al. 2004), adipocyte (Dos Santos et al. 2002), neuroblastoma (Watters et al. 1997), or breast cancer cell lines (Migliaccio et al. 1996). This evidence concerns the gene MAPK3 and breast carcinoma.