The greater benefit of an AI in ER+/PgR− patients compared to ER+/PgR+ tumours was significant in the ATAC trial (Dowsett et al, 2005), and was supported by the ABCSG/ARNO trial (Jakesz et al, 2005a) and to some extent by the IES trial (Coombes et al, 2004b). This evidence concerns the gene PGR and neoplasm.