A dose-responsive drop in Rac1/Cdc42, WAVE2, phospho-Rac1/Cdc42, Arp2, and Arp3 was seen in MDA-MB-231 mammary tumor cells after 4 days of mangiferin therapy, in contrast to cells in respective control groups, according to a Western blot analysis. The gene discussed is CDC42; the disease is breast cancer.