Of note, as determined by MTT assay, proliferation of CD34+ cells isolated from human cord blood was not affected even at the concentrations up to 800 μM after 72 hours of treatment, suggesting that primary APL cells responded to Catechins in a similar way as NB4 cells and Catechins exerted no severe cytotoxic effect on normal hematopoietic precursors (Figure 4F). The gene discussed is CD34; the disease is acute promyelocytic leukemia.