In a recent study, we found high serum concentrations of two immuno-modulators in NF1 patients with MPNSTs: the insulin-like growth factor-binding protein 1 (IGFBP-1) and the Chemokine Regulated upon Activation, Normal T cell Expressed and Secreted (RANTES) [7]. The gene discussed is IGFBP1; the disease is neurofibromatosis type 1.