Green tea: prevention and treatment of cancer by nutraceuticals

Green tea1 has always been considered by the Chinese and Japanese peoples as a potent medicine for the maintenance of health, endowed with the power to prolong life. Recently, Yean Lee and colleagues' looked at the effects of the main active green tea constituent, epigallocatechin-3-gallate (EGCG) on chronic lymphocytic leukaemia B cells isolated from leukaemic patients. These cells are characterised by their resistance to apoptosis because they secrete and bind vascular endothelial growth factor (VEGF), a potent angiogenic cytokine that also acts as a crucial survival factor for tumour cells. The researchers showed that addition of EGCG to these cells markedly decreased VEGF-receptor phosphorylation, leading to the disruption of the VEGF-dependent autocrine pathway that protects the cells from apoptosis and cell death.