Use of a newly established human cell line (SU-CCS-1) to demonstrate the relationship of clear cell sarcoma to malignant melanoma.

A new tumor cell line, designated SU-CCS-1, was established from the malignant pleural effusion of a 16-year-old Caucasian girl with clear cell sarcoma. Morphological studies at the light- and electron-microscopic levels revealed similar features between the SU-CCS-1 cells and the primary tumor. Ultrastructural and cytochemical techniques showed that both the SU-CCS-1 cell line and the original tumor were amelanotic in nature. The malignant derivation of the SU-CCS-1 cell line was demonstrated by intracranial and s.c. heterotransplantation in the nude, athymic mouse and by cytogenetic analysis which showed that the cell line had a hypodiploid chromosome number and several karyotypic abnormalities. Live-cell radioimmunoassay procedures using a large panel of monoclonal antibodies directed against tumor-associated antigens revealed that, phenotypically, SU-CCS-1 closely resembled melanoma tumor cell lines. Immunological assays for the detection of neuroendocrine-associated peptides, hormones, and enzymes revealed that, like melanoma, the SU-CCS-1 cell line was actively producing alpha-melanotropin, S-100 antigen, and nerve growth factor. A notable difference between these tumor types was the capacity of SU-CCS-1 to produce bombesin, an active neuropeptide whose synthesis has been found in cell lines from patients with small cell carcinoma of the lung. From these studies, we concluded that the SU-CCS-1 cell line is phenotypically similar to melanoma, yet displays unique characteristics which distinguishes it from other sarcomas. The availability of an established clear cell sarcoma cell line will greatly facilitate further studies aimed at uncovering the histogenesis of this rare cancer.