[Glial fibrillar acidic protein in peripheral nerve tumors in rats].

Twenty-seven peripheral nerve tumours of BD VI rats from the histological archives of the International Agency for Research on Cancer were immunohistochemically studied for GFAP reactivity. Twelve tumours were induced by nitrosoethylurea (NEU) and 13 tumours were spontaneous. Thirteen tumours (7 of them NEU-induced and 6 spontaneous) revealed GFAP-reactivity which was relatively high (large areas of GFAP-positive cells) in 4 neoplasms (3 induced and 1 spontaneous). GFAP-positive tumours were not histologically distinguishable from GFAP-negative tumours. GFAP-positive tumours were also positive for S-100 protein although the incidence and the intensity of GFAP-reactivity were much lower than that of S-100 reactivity. Early NEU-induced schwannomas were negative for GFAP and S-100; all GFAP-and S-100-positive tumours were large neoplasms with an invasive growth. GFAP-positivity was observed in both solid and cystic schwannomas. The results of the study represent the additional data on the observation of GFAP outside of the central nervous system.