ABSTRACT
The antitumor activity of Kupffer Cell (KC) is a relatively recent finding. Most investigators found that the in vitro destruction of tumor targets by KC, like monocyte and peritoneal macrophages, occurs by a nonphagocytic process and requires cell contact and prolonged incubation. These results suggest that the cytotoxicity displayed by KC depends upon both the activation state of KC and the nature of the tumor target cells. Experimental evidence suggests that Natural Killer cells are important effector cells in controlling hematopoiesis, infections, and surveillance against tumor cells. The primary role of these cells in neoplasia appears to be directed against blood-borne tumor cells during the intravascular phase of tumor metastasis. A number of hepatocyte-derived protein factors have been shown to possess immunomodulatory properties. In summary, hepatocytes can potentially produce a variety of mediators and alter the host-tumor relationships through modification of host immune responses and by a direct inhibition of the growth or invasion of tumor cells.
