A melanin-producing cell line derived from ascites of a patient with malignant melanoma.

A melanoma cell line (PL-14), established from ascites of a patient with malignant melanoma, has continued to produce melanin for 4.5 years after the initial cultivation. The cultured cells have granules which were stained black with Masson-Fontana stain, and positive to the dihydroxyphenylalanine (DOPA) reaction. Melanosomes and premelanosomes were detected in most of the cells by electron microscopy. Doubling time of the cell line was 72 hr and the mode of chromosome number was 48, ranging from 40 to 86. Inoculation of the cultured cells into the hamster cheek pouch produced pigment-producing tumors.