Epstein-Barr virus (EBV) is a kind of DNA tumor virus. Previous Studies on the tumorigenic mechanism of EBV mainly focus on human B lymphocyte. Now there are evidences that EBV exists in human T-cell lymphoma. Exploration in recent years show that EBV could infect T lymphocyte and likely play an important role in the pathogenesis of T-cell lymphoma. Investigation of molecular biological effect of LMP1 in T cell will be helpful for us to understand the approach and mode of EBV infecting T lymphocyte as well as the mechanism of T-cell lymphoma development.

PURPOSE To provide evidence for the relationship between degree of invasion and tumor metastasis. The tumor cells of transplantable mouse histiocytic sarcoma (L1) were inoculated at the right hind footpads of inbred 615-strain mice. METHODS Once bearing the tumor, all the mice were sacrificed respectively on the 1st. 3th, 5th. 10th, 20th, 30th, and 40th day as to observe the degree of tumor invasion and the process of tumor metastasis. RESULTS When the degree of tumor invasion was grade Ⅲ or Ⅳ , the metastasis of tumor cells was found earliest in draining lymph nodes. However, the tumor metastasis in lung appeared later than in lymph nodes. CONCLUSION According to the time of tumor growth and degree of invasion and metastasis, the authors suggest a new classification for cancer staging, namely, latent, invasive and metastatic stages. During the stage of tumor invasion, it is redivided into early, middle and late invasive phases. During the stage of tumor metastasis, it is redivided into early, middle and late metastatic phases.

Objective To compare the different expression of EBNA-1 in the normal human lymphocytes and in the EBV-induced lymphomas so as to provide the basis for studying the mechanism of the EB virus-induced lymphoma. Methods Animal model of EBV-induced lymphoma was constructed in SCID mice. EBNA-1 gene expression level was detected by real-time PCR and Western blot. Results EBV-induced lymphomas in animal model were replicated. EBNA-1 gene was expressed both in normal human lymphoma cells and 3 EBV-induced lymphoma cells. In EBV-induced lymphoma cells , the expression was up-regulated 11 683 times than in normal lymphocytes. Western blot results showed that the expression of EBNA-1 protein in induced lymphoma cells increased significantly compared with that in normal lymphocytes. Conclusions EBNA-1 expression in EBV-induced lymphoma cells is up-regulated than in normal lymphocytes. EBNA-1 may play an important role in the development of EBV-induced lymphoma.

Objective:To investigate effects of miR-503 on cisplatin sensitivity in BEL-7402 cells by targeting of bcl-2.Methods:MiR-503 and bcl-2 mRNA expression levels in hepatocellular carcinoma cells were measured by real-time quantitative (qRT)-PCR;Bcl-protein level was detected by Western blot;miR-503 mimics were transiently transfected to the BEL-7402 cells by liposome transfection;potential target genes of miR-503 were predicted by Bioinformatics software;miR-503 potential targets were validated by dual luciferase activity;and the cell viability was measured by MTT assay.Results:MiR-503 level was down-regulated and Bcl-2 protein expression level was up-regulated in BEL-7402 cells compared with HL-7702 cells.MiR-503 could interact with bcl-2 and inhibit its expression.Cell vitality with miR-503 transfection was significantly reduced compared to that in the negative control.Conclusion:MiR-503 may enhance the sensitivity of BEL-7402 cells to cisplatin and inhibit the cell proliferation by targeting bcl-2.

AIM: To establish nasopharyngeal carcinoma(NPC) cell lines stable expressing NPC-derived latent membrane protein 1(LMP1) gene. METHODS: General expression vector and epithelium-specific expression vector of NPC-derived LMP1 gene were constructed by using recombinant techniques, then transfected these vectors into a poor differentiated NPC cell line named CNE-2 ,integration and expression of N-LMP1 in CNE-2 cells were detected by PCR,RT-PCR and Western blot. RESULTS: (1) General expression vector and epithelium-specific expression vector of NPC-derived LMP1 gene were constructed successfully.(2) It showed that N-LMP1 gene expressed in CNE-2 cells correctly. CONCLUSION: The first NPC cell lines which stable express NPC-LMP1 were established. The cell lines obtained will provide important basis for exploring the role of NPC-LMP1 in nasopharynx carcinogenesis.