In an effort to understand green tea’s effects on breast tissue, we conducted standard immunohistochemical (IHC) analysis of markers of cell proliferation (Ki-67), apoptosis (cleaved caspase-3 (casp-3), and angiogenesis (CD34) in patients diagnosed with breast cancer to investigate the short-term clinical effects of green tea supplementation. The gene discussed is MKI67; the disease is breast cancer.