Effect of heat shock protein-90 (HSP90) and vascular endothelial growth factor (VEGF) on survival in acute lymphoblastic leukemia: an immunohistochemical study.

Background: The significance of vascular endothelial growth factor (VEGF) and heat shock protein-90 (HSP90) has received only limited attention especially in acute lymphoblastic leukemia (ALL). In this study, we assessed expressions of HSP90 and VEGF in bone marrow samples of patients with ALL and effect of these expression quantities on the mean overall survival.

Patients And Methods: Using immunohistochemical methods, we assessed expression of HSP90 and VEGF in 22 cases of ALL.

Results: Expression of HSP90 was detected in 19/22 (86.4%) and 3/22 (13.6%) of patients with ALL, for strongly positive and moderate-weakly positive, respectively. Negative HSP90 expression was not detected in patients with ALL. Expression of HSP90 in patients with ALL and in control group were statistically significant (P<0.001), however, did not reflect the mean overall survival (P=0.910). Mean OS was evaluated 992±181 and 724.8±88.2 days for moderate-weak and high HSP90 expression, respectively. VEGF expressions were not significantly different between ALL and control groups (P<0.087). We did not find any relationship between HSP90 and VEGF expressions in bone marrow specimens of patients with ALL.

Conclusion: This study demonstrated that HSP90 expression grades in patients with ALL were significantly higher than that in controls and presence of strong HSP90 expression was associated with worse overall survival. VEGF expression in patients with ALL was not different from that in control samples. Determination HSP90 with immunohistochemical method in bone marrow can provide information about prognosis.