N‐Nitroso‐N‐ethylurea‐induced Hamster Melanoma: A New Method for Efficient Induction and Schwannian Differentiation of Melanoma

摘要

Melanocytic tumors as well as multiple neurofibromas were induced in 35 of 88 Syrian golden hamsters by a single s.c. administration of 100 mg/kg of N‐nitroso‐N‐ethylurea applied 48 h after birth. The lesions were all observed proliferating in the dermis and demonstrated melanosomes and premelanosomes. High cellularity, nuclear atypia and transplantability of the tumors in outbred hamsters suggested a malignant nature. Some of the melanomas were morphologically heterogenous and contained Schwann‐like cells as minor components. In addition, transplantation of the melanomas resulted in increased schwannian differentiation even for primary tumors which did not contain any Schwann‐like cell foci. One of the transplanted melanomas mimicked malignant peripheral nervous tumor. Schwannian differentiation was also proved by the fact that glial fibrillary acidic protein was positive in 22.2% of the cases. The present results suggest that the induced hamster melanomas originate from neural crest‐derived cells which are able to differentiate into both melanocytes and Schwann cells.