Cell cycle-associated proteins in melanotic neuroectodermal tumor of infancy

Objective. The purpose of the present study was to compare the immunohistoc hemical expression of cell cycle-associated proteins in neuroblastic and me lanocytic cell populations of melanotic neuroectodermal tumor of infancy. Study design. Three cases of melanotic neuroectodermal tumor of infancy wer e selected. The immunohistochemical expression of MDM-2, p53, proliferating cell nuclear antigen, cyclin D1, and cyclin A was assessed through use of the streptavidin-biotin-peroxidase complex technique. Results. Positive immunostaining for MDM-2, proliferating cell nuclear anti gen, cyclin D1, and cyclin A was occasionally observed in the large melanin -containing epithelioid cells. Conclusions. These data suggest that MDM-2 expression may be important for the development of melanotic neuroectodermal tumor of infancy and that the melanocytic cell population, not the neuroblastic one, is the proliferative component of the tumor.