In situ observation of lymphocyte-tumor cell interaction in human lung carcinoma

Of thirty surgical specimens of human lung carcinoma examined with electron microscopy, eleven were found to contain killer cells (cytotoxic lymphocytes). Nearly one-third of the killer cells showed the polarization of their cytoplasm in which Golgi apparatus, dense granules or centrioles could be seen. The tumor cells conjugated by the killer cells showed lesions to varying degrees, including loss of cell membranes, alterations of cell organelles, even cell necrosis. The killer cells frequently penetrated into the cytoplasm, even the muclei of the tumor cells. The results of the present study suggest that the lymphocyte-mediated tumor cell lysis may exist in the microenvironment of human lung carcinoma and that some of these cytotoxic lymphocytes may kill their target cells by a similar mechanism of the pore formation or granule exocytosis model, but some different aspects were also observed, as compared with the results of the in vitro studies.