AIM To investigate the correlation betweenlymphogenous metastasis and matrix metalloproteinases(MMPs)activity and the expression of Fas ligand of tumorcells in lymph nodes.METHODES Fifty-six inbred 615-mice were equallydivided into 2 groups and inoculated with Hca-F and Hca-Pcells.Their lymph node metastatic rates were examined.Growth fraction of lymphocytes in host lymph nodes wasdetected by flow cytometry.The Hca-F and Hca-P cellswere cultured with extract of lymph node,liver or spleen.The quantity of MMPs in these supernatants was examinedby zymographic analysis.The expression of Fas ligand,PCNA,Bcl-2 protein of Hca-F and Hca-P cells in the micewere examined by immunohistochemistry.The apoptosissignals of macrophages in lymph nodes were observedwith in situ DNA fragmentation.RESULTS On the 28~(th) day post-inoculation,the lymphnode metastatic rate of Hca-F was 80%(16/20),whereasthat of Hca-P was 25%(5/20).The growth fraction oflymphocytes was as follows:in the Hca-F cells,theproliferating peak of lymphocytes appeared on the 14~(th) daypost-inoculation and then decreased rapidly,while in Hca-P cells,the peak appeared on the 7~(th) day pest-inoculationand then kept at a high level.With the extract of lymphnode,the quantity of the MMP-9 activity increased(P<0.01)and active MMP-9 and MMP-2 were produced byboth Hca-F and Hca-P tumor cells,which did not produceMMPs without the extract of lymph node or with theextracts of the liver and spleen.The expression of FasLigand of Hca-F cells was stronger than that of Hca-P cells(P<0.01).The expressions of PCNA and Bcl-2 protein ofHca-F cells in the tumors of inoculated area were the sameas that of Hca-P cells.In situ DNA fragmentation showedthat the positive signals of macrophages were around Hca-F cells.CONCLUSION Secretion of MMPs which was associatedwith metastatic ability of Hca-F and Hca-P tumor cellsdepends on the environment of lymph nodes.Theincreased expression of Fas ligand protein of Hca-F tumorcells with high lymphogenous metastatic potential in lymph nodes may help tumor cells escape from beingkilled by host lymphocytes. AIM To investigate the correlation between lymphogenous metastasis and matrix metalloproteinases (MMPs)activity and the expression of Fas ligand of tumor cells in lymph nodes.METHODES Fifty-six inbred 615-mice were equallydivided into 2 groups and inoculated with Hca-F and Hca-Pcells. Their lymph node metastatic rates were examined.Growth fraction of lymphocytes in host lymph nodes wasdetected by flow cytometry.The Hca-F and Hca-P cellswere cultured with extract of lymph node,liver or spleen.The quantity of MMPs in these supernatants was examinedby Zymographic analysis.The expression of Fas ligand,PCNA,Bcl-2 protein of Hca-F and Hca-P cells in the micewere examined by immunohistochemistry.The apoptosis signals of macrophages in lymph nodes were observedwith in situ DNA fragmentation.RESULTS On the 28~ (th) day post-inoculation, the lymphnode metastatic rate of Hca-F was 80% (16/20), whereas that of Hca-P was 25%(5/20).The growth fraction of lymphocytes was as follows:in the Hca -F cells,theprolife The rating peak of lymphocytes appeared on the 14~(th) daypost-inoculation and then as quickly rapidly, while in Hca-P cells, the peak appeared on the 7~(th) day pest-inoculation and then kept at a high level.With the Extract of lymphnode, the quantity of the MMP-9 activity increased (P<0.01) and active MMP-9 and MMP-2 were produced byboth Hca-F and Hca-P tumor cells, which did not produceMMPs without the extract of lymph node Either or with theextracts of the liver and spleen.The expression of FasLigand of Hca-F cells was stronger than that of Hca-P cells(P<0.01).The expressions of PCNA and Bcl-2 protein ofHca-F cells in the tumors of Inoculated area were the sameas that of Hca-P cells.In situ DNA fragmentation showedthat the positive signals of macrophages were around Hca-F cells.CONCLUSION Secretion of MMPs which was associatedwith metastatic ability of Hca-F and Hca-P tumor cellsdepends on the Environment of lymph nodes.The induced expression of Fas ligand protein of Hca-F tumor cells with high lympHogenous metastatic potential in lymph nodes may help tumor cells escape from being victimed by host lymphocytes.