We studied the migratory and invasive capacity of different cell lines: the luminal breast cancer MCF7, and two basal-like cell lines: MDA-MB-231 with wild-type BRCA1, and HCC1937 with mutated BRCA1. RhoA and RhoB RNA silencing and Rho inhibitor (Rhosin) treatment were tested to evaluate their effect on migration and invasion. This evidence concerns the gene BRCA1 and breast cancer.