[Presence of cell fusions in human malignant glioma]

The observation in malignant glioma of multinucleated cells possessing nuclei at different stages of the cell cycle, micrographs never encountered in benign glioma, led us to propose the hypothesis that, at least in this series of tumors, cell fusion was a criterion of malignancy. We tried to confirm this hypothesis by grafting malignant human gliomas into the brains of new-born mice for the purpose of making hybrid cells possessing human and murine characteristics conspicuous, we found these same multinucleated cells in these grafts. We demonstrated the hybrid nature of these cells by means of a fluorochrome, 33,258 Hoechst, which has the property of fixing itself selectively in the chromocentres of mice. We found quenched human cells, very fluorescent mice cells, and hybrid cells with syncaryons presenting a mixture of fluorescent and quenched chromocentres. These malignant cells are therefore capable of fusing with normal cells at a frequency which remains to be determined.