The results indicate panobinostat not only effectively reduces the survival rate of both NB4 and APL primary cells, but also eliminated the stimulatory survival effect of microenvironment signals transduced by mesenchymal stem cells (MSC) on APL cells by incorporating PI3K inhibitor when APL cells are co-cultured with MSC [147]. This evidence concerns the gene PIK3CB and acute promyelocytic leukemia.