BBC3 and leukemia: In vivo studies have shown that shRNA-mediated silencing of ZMAT3 in haematopoietic stem/progenitor cells (HSPCs) caused development of leukaemia/lymphoma in transplant recipient mice only when PUMA and p21, the critical effectors of TRP53-mediated apoptosis [12, 13] and cell cycle arrest [14] respectively, were also absent [5].