ESTABLISHMENT AND CHARACTERIZATION OF HUMAN VAGINAL MALIGNANT-MELANOMA XENOTRANSPLANTS

Human vaginal malignant melanoma represents rare gynecological maligna ncies of poor prognosis. We have established a melanoma tumor line in nude mice, designated Mela-1, and have examined the histological and b iological characteristics of this tumor. The Mela-1 tumor has preserve d the histological, histochemical and biological characteristics of ma lignant melanoma even after 20 passages. Tumor cells are of epitheloid shape varying in size. An ultrastructural study revealed that the tum or cells were characterized by the presence of cells with deeply inden ted nuclei, and both types of melanosomes, eumelanosomes and pheomelan osomes, in various stages of maturation with vesiculo-globular bodies in the cytoplasm. Melanin analysis of the tumor indicated the Mela-1 t umor to be pheomelanic. Immunohistochemical examinations revealed that the Mela-1 cells were stained positively by melanoma-associated antib ody (NKI/C3) and by antibodies for S-100 protein and vimentin, and neg atively for keratin and CEA. The levels of AFP, CA125 and CEA in sera of tumor-bearing mice were within normal range. The 5-S-cysteinyldopa level in sera of tumor bearing mice correlated well with the size of t he tumor. Chromosomal analysis showed the human karyotype with great h eterogeneity and a modal number of 102 chromosomes. Thus the Mela-1 tu mor will be useful in establishing the biological characteristics in t he search for an effective treatment of human malignant melanoma of th e vagina.