Intercellular communication and tissue growth : V. A cancer cell strain that fails to make permeable membrane junctions with normal cells.

A method is described for testing communication between a normal and a cancerous cell in culture without inserting microprobes into either cell; microprobes are put into other normal cells coupled to the normal cell in question. It is shown with this method that a cell strain (class-A), of epithelial morphology, isolated from Morris' liver tumor (H-5123) fails to make communicative junctions with several types of normal cells; small inorganic ions and fluorescein do not pass from the normal cells to the class-A cells (they do pass from the normal cells to normal cells, even between normal cells of different type). The class-A cells also appear incapable of junctional communication among themselves. The cells of class-A are cancerous: they are not 'contact inhibited' by each other or by the normal cells and they form malignant tumors when injected into test animals. Another cell strain (class-B), of fibroblastic morphology, derived from the same liver tumor as class-A makes communicative junctions readily. This strain is 'contact inhibited' and does not produce tumors when injected into the animals.