Proliferation of each cell line (n ¼ 3 per treatment) was monitored with or without ECG or EGCG at concentrations of 0, 25, 50, 75 and 100 mM. The dosimetric results plotted in Fig. 6 shows concentration-dependent suppression of cell growth by ECG and EGCG. The suppressive effect on cell density was striking at higher concentrations of ECG and EGCG. ECG was a more potent inhibitor of cell growth than EGCG. At 25 mM of EGCG, cell numbers for HH870 and DU145 were significantly higher than control values. Based on the results plotted in Fig. 6 , IC50 values were calculated. The IC50 values are 24-30 mM for ECG, versus 42-89 mM for EGCG (Table 2 ). ECG suppressed growth at all higher concentrations tested (Fig. 6) , whereas EGCG significantly (P < 0.05) enhanced proliferation of CaP cells at 25 mM, a finding relevant to chemoprevention trials with EGCG only.