Most cytotoxic drugs kill cells by instigating the process of apoptosis and
it has been suggested that apoptotic markers may provide an indication of
tumour chemosensitivity. The aim of this study was to determine if such a r
elationship exists in acute myeloid leukaemia (AML). The levels of spontane
ous apoptosis, bcl-2 and bax were evaluated in 56 newly diagnosed AML patie
nts to determine if they correlated with a response to cytotoxic therapy. S
pontaneous apoptosis was lower, but bcl-2, bax and the bcl-2/bax ratio were
higher in AML compared with normal individuals. AML patients with high bax
expression at diagnosis had significantly better prognosis for disease-fre
e survival, event-free survival and overall survival (P = 0.016). In the st
andard risk group, high bax expression was in keeping with significantly im
proved survival. Multivariate analysis revealed bax to be an independent pr
edictor of survival. There was a significant reduction in bcl-2 and bax exp
ression when AML patients entered complete remission and also in relapsed A
ML, patients who entered a second remission. This study suggests that bax i
s a useful prognostic indicator in AML and may assist with therapeutic deci
sion-making for patients in the standard risk category.