Changes of serum growth factors (IGF-I & IGFBP-2) and prediction of response to chemotherapy in patients with acute myeloid leukemia.

Insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) possess mitogenic properties promoting cellular proliferation and inhibiting cellular apoptosis. Thus, IGF-system may play a role in tumor proliferation. In the present study, we investigated IGF-I and IGFBP-2 in patients with acute myeloid leukemia (AML) for their predictive value to identify patients who could be responsive to conventional induction chemotherapy. Serum levels of IGF-I and IGFBP-2 were measured (using commercial ELISA kits) in 22 patients with AML. Following treatment, patients were followed up 14 days after the induction cycle to determine if they achieved hematological remission or not. Accordingly, patients were divided into two groups: Responders (10 patients) and Non-Responders (12 patients). No significant difference was observed in IGF-1 between Responders and Non-Responders, neither before (79.26 +/- 4.568 pg/ml vs 72.225 +/- 3.62 pg/ml, respectively) nor after induction cycle (74.87 +/- 3.669 pg/ml vs 69.783 +/- 4.329 pg/ml, respectively). However, IGFBP-2 was significantly lower in Responders than in Non-Responders both at diagnosis (4250 +/- 155.099 pg/ml vs 6866.67 +/- 352.122 pg/ml, respectively) as well as after induction cycle of chemotherapy (4130 +/- 324.225 pg/ml vs 7150.00 +/- 265.290 pg/ml, respectively). It is concluded that, serum IGFBP-2 is considered as an independent factor that adds additional information for the prediction of relapse or treatment failure and patients with concentration > or = 4900 pg/ml at diagnosis are suspected to be nonresponders to conventional induction chemotherapy.