The expression of bcl- 2 and boax proteins and their clinical relevance in all and cll patients

Abstract EN

The products of the bcl-2 gene prolong survival of lymphohemopoietic cells by inhibition of programmed cell death, whereas, bax has an antagonistic role against the function of bcl-2.

In the present study we have examined the expression of bcl-2 and bax proteins in cases of ALL and CLL aiming to establish if measurement of expression of these proteins could be of prognostic relevance.

Using quantitative western blotting (WB) and immunocytochemistry(IC) we determined the level of expression of bcl-2 and bax proteins in 42 and 20 newly diagnosed cases of ALL and CLL, respectively.

Ten healthy individuals were taken as control for bcl-2 and bax expression by IC and WB.

By WB, bcl-2 protein was detectable in 39 / 42 of ALL cases and all CLL cases studied.

Bax protein expression using WB revealed detectable levels in 37/42 ALL cases and all CLL cases studied.

The level of bcl-2 and bax expression in CLL patients was significantly higher than in ALL patients p = 0.003 and 30.00, respectively.

The level of bcl-2 expression in CLL patients was significantly higher than in ALL patients and control group, p = 0.006.

Our results confirmed a higher sensitivity of WB in detection of these cell cycle proteins when compared to IC.

Higher bcl-2 expression was more evident among ALL patients above 18 years, p = 0.03.

The level of bax expression was significantly higher in patients with total leukocytic counts (TLC) ³ 50 x 109 / L, p = 0.02.

Although no relation was found between bcl-2 and bax expression and an increased probability of relapse yet, overexpression of bax (but not bcl-2) was associated with an unfavorable disease outcome, p = 0.02.

In cases with strong expression of bcl-2, an over expression of bax as well was detected by WB.

This finding reflects the fact that it is the balance rather than the level of either protein product that determines the influence of these cell cycle proteins on prognosis of ALL.