TFF1 and breast cancer: As shown in Fig. 3, expression levels of the progesterone receptor (PgR) (Fig. 3a), growth regulation by estrogen in breast cancer 1 (GREB1) (Fig. 3b), trefoil factor 1 (TFF1, also known as pS2) (Fig. 3c) and amphiregulin (AREG) (Fig. 3d) were measured after 24 h of treatment with 10−9 M E2 and different doses of glyceollin I or II either alone or in combination with E2.