IGF1R and melanoma: For example, IGFBP2 modulates the bioactivity of IGF1/IGF1R, and is mainly synthesized in the choroid plexus and leptomeninges.37 It has been suggested that IGFBP2 levels in CSF may correlate with CNS malignancy.38,39 Similarly, IGF1 activity in melanoma LMD may determine disease prognosis.2