Spontaneous metastasis of clonal cell subpopulations of human lung giant cell carcinoma after subcutaneous inoculation in nude mice

Abstract Four sub-lines (strain A, C, D, E) were isolated from a human lung giant cell carcinoma cell line (PLA-801) by the single cell cloning technique. The incidence of spontaneous metastasis was higher in strain D, moderate in strains A, E and lower in strain C after they were inoculated subcutaneously into the nude mice. The lung and lymph-nodes were the major target organs of metastasis. Morphological studies (light microscope, electron microscope and immunohistochemistry) showed that the cytoplasm of metastatic tumor cells was rich in microfilament and positive for Vimentin. The results strongly support the theory on tumor cell heterogenicity. In addition, these clones, especially strains D and C, could be an ideal model for the study of tumor metastasis.