In MCF-7 breast cancer cells treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), luteolin suppressed the expression of interleukin 8 (IL-8) and the activation of matrix metalloproteinase 9 (MMP-9), which play important roles in breast cancer proliferation. The gene discussed is CXCL8; the disease is breast carcinoma.