GREB1 and breast carcinoma: They did, however, identify many of the genes found to be significantly differentially expressed according to serum estradiol in breast carcinomas in the current study, such as AREG, GREB1, TFF1 and TFF3. Going back to our normal samples, we see that several of their genes (including AREG, GREB1, TFF1 and TFF3, GATA3 and two SERPIN-genes) are differentially expressed in our normal breast tissue, but did not reach statistical significance (Additional file 4).