Furthermore, in a xenograft tumor model, S-equol inhibited MDA-MB-231 cell-derived tumor growth (Figure 5B), accompanied by significant reduction in the number of tumor cells expressing Ki-67, an established marker for cycling cells (Figure 5C), and with concomitant increase in pY36 signal in xenografted tumors (Figure 5D). The gene discussed is MKI67; the disease is neoplasm.