To test if verrucarin A-mediated downregulation of SRC-3 corresponds with cell growth inhibition, MCF-7, A549, H1299, and PC-3 cancer cells were treated with verrucarin A at different concentrations (0, 0.2, 0.5, 1, 2, 5, 10, and 20 nM) for 72 h and cell growth was determined by MTS assay. The gene discussed is NCOA3; the disease is cancer.