ORIGINAL ARTICLE Expression of components of the IGF signalling system in childhood acute lymphoblastic leukaemia

Background: Alterations in the insulin-like growth factor (IGF) system have been reported for different tumours. They are of particular interest in the search for new prognostic and therapeutic approaches in cancer. In childhood acute lymphoblastic leukaemia (ALL) the amount of “tumour mass ” at diagnosis can exceed 1 kg. To understand the endocrine, paracrine, and autocrine potential of the malignant transformed progenitor cells, the ability of these cells to express components of the IGF system needs to be investigated. Aim: To characterise the expression pattern of genes of the IGF system in malignant lymphoblasts of children suffering from ALL. Methods: Reverse transcription polymerase chain reaction of Ficoll separated mononuclear cells from 142 children with ALL, 127 cord blood samples, and 55 blood samples of age matched controls were studied. Results: The expression of IGF-I, IGF-II, IGF binding protein 5 (IGFBP-5), and CTGF (IGFBP-rP2) was seen in a higher proportion of mononuclear cells of patients with ALL than in controls. Patients with ALL who were in continuous remission had a lower percentage of IGFBP-2 and IGFBP-3 expressing mono-nuclear cells at diagnosis than did those who developed a relapse. Only malignant lymphoblasts of