In patients with ER-positive (ER+) tumours (28/56), fulvestrant caused a significant reduction in median ER index (0.73 vs 0.02 pre- and post-treatment, respectively; P<0.001) and almost abolished PgR expression; the median PgR index was reduced from 0.50 to 0.01 post-treatment (P<0.05; n=37) in ER+ tumours. Here, PGR is linked to neoplasm.