SNAI1 and neoplasm: Notably, except for a slight increase in Slug in a longer treatment, the expression of E-cad, Vim, Snail, and p-Fra1 in p18−/− tumor cells in culture was not affected by E2 either, whereas, the expression of Vim, Snail, and Slug in p18−/−;Brca1MGKO tumor cells was clearly enhanced by E2 under the same culture conditions (Fig. 3e, g and Additional file 6: Figure S6A-D).