This antibody labels immature melanosomes in normal and pathological tissues. Thus the antibody labels fetal and neonatal melanocyte and junctional nevi. Intradermal nevi and normal resting adult melanocytes are negative. Positive staining does not provide distinction between benign and malignant melanocytic proliferation.\\nThis antibody may be useful for the identification of melanoma and other tumors showing melanocytic differentiation. Differential identification is aided by the results from a panel of antibodies. In general, tumors of epithelial, lymphoid, glial, and mesenchymal origin are negative.