Increasing occurence of tumour cell -- tumour cell emperipolesis in the regenerating JB-1 ascites tumour.

During the investigation of JB-1 ascites tumour cells in recurrent growth several cases of emperiopolesis were observed. Different types of emperipolesis are presented. Light microscopical serial sections, autoradiography and transmission electron microscopy indicate that the cells involved in emperipolesis are separate cells, and the authors suggest that cytopagocytosis is the initial mechanism in the development of emperipolesis.