Fetal antigen 1, a member of the epidermal growth factor superfamily, in neurofibromas and serum from patients with neurofibromatosis type 1

Fetal antigen 1 (FA1) is a 26-32 kDa glycoprotein containing six epidermal growth factor-like repeats closely related to the delta/notch/serrate prote ins in Drosophila. PA1 has been shown to be involved in cell differentiatio n in a juxtacrine/paracrine manner. As neurofibromatosis type 1 (NF-1), als o called von Recklinghausen disease, involves aberrant growth of tissues de rived from the neural crest, the expression of FA1 was examined in neurofib roma skin biopsies and serum from patients with NF-1. FA1 was found in the spindle cells of all (n = 10) skin tumour specimens from adult NF-1 patient s, whereas normal dermis was FA1 negative. In adults, the serum FA1 levels were significantly higher in NF-1 patients (n = 13) than in normal healthy controls (n = 177) (P = 0.037). In the group of children with NF-1 (n = 9), significantly higher serum FA1 levels were observed in those known to have complications with cerebral or spinal involvement (n = 4) (P = 0.014). The presence of FA1 in neurofibroma specimens and the elevated serum levels in patients with NF-1 suggests that FA1 may be involved in the pathogenesis o f NF-1, perhaps acting as a growth promoting factor.