The in vitro effect of chemopreventive agents can be studied when tumor cells are in a matrix (1, 4, 27) or in a suspension (28, 29) . We used the suspension method because it exposes the entire cell surface to the chemotherapeutic agent. Our findings confirm an earlier report that used the matrix method to show that ECG is more potent than EGCG in suppressing the proliferation of DU145 CaP cells (4) . Thus reported differences in the relative efficacy of different catechins may not be due to differences in methodology.