Are elevated serum levels of IGFBP-2 after intensive chemotherapy of childhood acute lymphoblastic leukemia a risk factor of relapse?

INTRODUCTION In the study we investigated the association between IGFs, their binding proteins and pathogenesis as well as prognostic factors of relapse of childhood ALL. MATERIAL AND METHODS In 43 children suffering from ALL, we observed 7 cases of relapse. We studied the serum levels IGF-I, IGF-II, IGFBP-3 and IGFBP-2 (expressed in SDS) in a subgroup with relapse (A) and in a subgroup without relapse (B) at diagnosis (1), after induction of remission (2) and after intensive chemotherapy (3). All comparisons were made with age-and sex-matched controls. RESULTS It was found that in subgroup A, the values of IGFBP-2 remained high at each stage of the investigation: 3.92 +/- 2.50 (1) 3.68 +/- 0.99 (2) 3.52 +/- 1.26 (3), whereas in the subgroup B they underwent a significant reduction from 3.87 +/- 1.86 (1) 3.45 +/- 1.25 (2) 2.15 +/- 1.84 (3), p = 0.02. In comparison to a control group, the correlations between IGF-I and IGFBP-3, and IGF-1 and IGFBP-2 were disturbed for the whole group of children at each stage of the investigation. However, at diagnosis we obserwed a negative correlation between IGFBP-2 and hemoglobin (r = -0.57 p = 0.0001). CONCLUSION Increased values of IGFBP-2 after intensive chemotherapy in children who subsequently underwent a relapse of the disease, suggest that IGFBP-2 levels might constitute a prognosis factor. However, this requires verification with a larger group of children. The negative correlation between values of hemoglobin and IGFBP-2 observed at diagnosis might further suggest the involvement of this protein in the process of leukemogenesis in children.