[A study on radiosensitivity cell line SSM-1 derived human oral malignant melanoma]

In order to study the efficiency of radiation therapy for human oral malignant melanoma, radiosensitivity for SSM-1 cell line derived from oral malignant melanoma was investigated by colony formation rate, survival curve, light microscopic observation, ultrastructual observation and immunocytochemical study with HMB-45. Survival curve of the SSM-1 cells was higher than that of cutaneous melanoma cell lines for radiosensitivity. Uniform masses of SSM-1 cells were found even with high dose irradiation. Giant cells and multiple nuclei cells were found after high dose irradiation. By ultrastructural observation, various nucleoi, chromatins and nucleus structures were found after low dose irradiation. Immunocytochemically, hot nodules of SSM-1 cells were found to have HMB-45 antibody, and the hot nodules increased after irradiation, suggesting increased number of melanosomes. By ultrastructural observation, the number of melanosomes was found to have increased after low dose irradiation. Radiosensitivity of SSM-1 cell line derived from oral malignant melanoma was higher than that of cutaneous melanoma cell lines, and the results of this study might support that radiotherapy is helpful for oral malignant melanoma.