Expression of bcl-2 and bax in cells isolated from B-chronic lymphocytic leukemia patients at different stages of the disease

B-Chronic lymphocytic leukemia (B-CLL) is an example of a human malignancy caused by alterations in the pathways of programmed cell death. In this disease the anti-apoptotic protein, bcl-2, is overexpressed and may lead to the prolonged survival of a malignant CLL clone. In the present study we examined the expression of bcl-2 and bax, which has an antagonistic role against the function of bcl-2, in cells from CLL patients at different stages of the disease, by immunoblot analysis. A direct association between the stage of the disease and the level of bcl-2 in the patients' cells was observed. At stages A and B, 33% and 29% of patients, respectively, expressed high levels of bcl-2, as opposed to 80% of patients at stage C (p=0.019). Bax level was not significantly associated with the stage of the disease, although patients at stage C had higher levels of bax. In this study we found a trend of association between bcl-2 and bax levels. Analysis including all patients revealed that 65% of the patients who expressed high levels of bcl-2 had high levels of bax (p=0.058). Of patients in stage C, 45% expressed high levels of both bcl-2 and bax while 50% and 42% of patients at stages A and B had low levels of both proteins.