Song et al (2001) first focused attention on the fas, fas ligand pathway as a potential mechanism of oestrogen-induced apoptosis in oestrogen-deprived breast cancer cells. Study of molecular mechanisms for oestrogen-induced tumour regression have recently been extended with the demonstration that oestrogen simultaneously collapses survival mechanisms (HER2/neu NFκB) in the Phase II SERM-resistant tumour, and enhances the expression of the fas receptor (Liu et al, 2003; Osipo et al, 2003) (Figure 3C, D). This evidence concerns the gene ERBB2 and breast cancer.