ESTABLISHMENT AND CHARACTERIZATION OF A MALIGNANT-MELANOMA CELL-LINE (YP-MEL) DERIVED FROM A PATIENT WITH NEUROCUTANEOUS MELANOSIS

A cell line, YP-MEL, was established from an intracranial malignant me lanoma occurring in a neurocutaneous melanosis (NCMsis) patient. The e stablished cell line was successfully cultured in serum-free medium wi th a doubling time of 41 b. The cells were refractile and small in siz e, with occasional pigmented giant cells. Histochemical and immunohist ochemical features were compatible with common malignant melanoma and its cell line. Chromosome analysis revealed many supernumerary chromos omes and marker chromosomes including double minutes (DMs). When trans planted into nude mice, YP-MEL formed tumors histologically consistent with the original tumor. Addition of sera to the medium caused cellul ar spreading and elongation of cytoplasmic processes with an increase of melanin contents and tyrosinase activity. Because there was no mela noma cell line derived from a NCMsis patient, YP-MEL might be a benefi cial tool for study on NCMsis.