These results are not only consistent with previous studies showing that PKC δ activation is required for regulating the production of iNOS in mouse peritoneal macrophages [27], human leukemia cells [46] and BV-2 cells [29], but also for the first time suggest that PKC β might play an important role in LPS-induced iNOS production in BV-2 cells even with its low levels of expression. The gene discussed is NOS2; the disease is leukemia.