GREB1 and neoplasm: This is in agreement with a recent study which showed a correlation of GREB1, PGR and TFF1 but not PDZK1 gene expression in ER +ve tumours with serum oestradiol levels in premenopausal patients.32 This latter study concurred with our earlier cross-sectional study but lacked the longitudinal aspect of the current study to allow consideration of within patient changes.