To address the question of the relevance of the ERα/Gα13/RhoA/ROCK/moesin signaling cascade on breast cancer cell movement, we pretreated T47-D or MDA-MB-468 (ER-) breast cancer cells with cytosine arabinoside (1-(β-D-arabino­furanosyl)­cytosine hydrochloride-Ara-C, 100μM), an inhibitor of DNA strand separation that prevents cell division (so to dissect the actions of estrogen on movement from those on cell proliferation), and we performed horizontal migration assays. Here, ESR1 is linked to breast cancer.