ELEVATED SERUM LEVELS OF IGFBP-2 FOUND IN CHILDREN SUFFERING FROM ACUTE-LEUKEMIA IS ACCOMPANIED BY THE OCCURRENCE OF IGFBP-2 MESSENGER-RNA IN THE TUMOR CLONE

Insulin-like growth factor-binding proteins (IGFBPs) are important mod ulators of IGF action. In 50 children suffering from acute lymphoblast ic leukaemia (ALL), we studied the serum levels of IGFBP-1, -2 and -3. The mean standard deviation score (SDS) values were estimated to be 0 .7, 3.1 and -1.7 for the IGFBP-1,-2 and -3, respectively, compared wit h the normal range defined by a SDS from -2 to +2. IGFBP-1 and -3 were normal, but for IGFBP-2 we found a significantly elevated serum level compared with control groups (P < 0.05). However, during chemotherapy this increased serum IGFBP-2 normalized. In addition, we found a corr elation between higher serum levels and the detection rate of the IGFB P-2 transcript in corresponding cells. In patients with ALL, the detec tion rates of IGFBP-2 mRNA were estimated to be 72% and 35% at the tim e of diagnosis and at day 33 of chemotherapy respectively; in the cont rol groups (healthy children and children at their initial presentatio n of diabetes mellitus), the values were 28% and 33% respectively. Bas ed on the correlation between IGFBP-2 serum levels and the correspondi ng gene expression as well as the normalization of IGFBP-2 levels duri ng chemotherapy, we concluded that the increased serum level mainly or iginated from the tumour clone itself, Furthermore, possible functiona l consequences of elevated IGFBP-2 were outlined.