BCL2 ONCOPROTEIN EXPRESSION IN ACUTE MYELOID LEUKEMIA j

Abstract

Programmed cell death (apoptosis ) is a nonnal process by which cells are eliminated during nonnal embryonic development and in adult life . Disruption of this nonnal process . resulting in illegitimate cell survival can cause developmental abnonnalities and facilitate cancer development (Sachs and Lotem,1993). Regulation of apoptosis is influenced by many factors which may up or down regulate the cell death program . .Inducers of apoptosis include growth factor or hormonal deprivation , cytokines , ligation of cell surface receptors , glucocorticoids and damage related inducers as heat shock and irradiation . On the other hand , apoptosis may be inhibited by hormones , some cytokines , CD40 ligation or by phannacologic agents . In addition , apoptosis is controlled by a set of regulatory genes . Proapoptotic genes include the Fas gene , one of the most important genes. inducing cell death . Other death genes include P53 oncosuppressor gene and c-myc oncogene . Conversly the antiapoptotic Bch oncoprotein plays a role in promoting cell survival and inhibiting apoptosis ( Campana and Clevaland ,1996). Bch was initially discovered at a translocation breakpoint in B-cell follicular lymphomas and was subsequently shown to have a role in preventing apoptosis ( Korsmeyer,l992; Vaux,1993). The protein is expressed in various fetal tissues destined •for long-tenn survival and adult tissues in which apoptosis serves an important homeostatic role ( Hockenberry et al., 1991 ; LeBurn et al., 1993 ).