EBAG9/RCAS1 expression in hepatocellular carcinoma: correlation with tumour dedifferentiation and proliferation

The roles of exosomal immune checkpoint proteins in tumors

Targeting immune checkpoints has achieved great therapeutic effects in the treatment of early-stage tumors. However, most patients develop adaptive resistance to this therapy. The latest evidence demonstrates that tumor-derived exosomes may play a key role in systemic immune suppression and tumor progression. In this article, we highlight the role of exosomal immune checkpoint proteins in tumor immunity, with an emphasis on programmed death ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), as well as emerging evidence on roles of T cell immunoglobulin-3 (TIM-3), arginase 1 (ARG1), and estrogen receptor binding fragment-associated antigen 9 (EBAG9) expressed by exosomes.

Extracellular vesicle-mediated EBAG9 transfer from cancer cells to tumor microenvironment promotes immune escape and tumor progression

The antitumor immune response is a critical defense system that eliminates malignant cells. The failure of the system results in immune escape and proceeds to tumor growth. We have previously showed that estrogen receptor-binding fragment-associated antigen 9 (EBAG9) is a relevant cancer biomarker and facilities immune escape of cancers from the immune surveillance. EBAG9 in cancer cells suppresses T-cell infiltration into tumor in vivo, whereas that in host immune cells functions as a limiter for T-cell cytotoxicity. Considering that EBAG9 plays immune suppressive roles in both tumor and microenvironment, we here questioned whether EBAG9 is a transferable protein from cancer to surrounding T cells and affects antitumor immune response. In this study, we showed that spontaneous development of prostate cancer was repressed in a model of Ebag9 knockout mice crossed with transgenic adenocarcinoma of the mouse prostate (TRAMP) mice. We identified TM9SF1 as a collaborative EBAG9 interactor, which regulates epithelial-mesenchymal transition (EMT) in cancer cells. Notably, extracellular vesicles (EVs) from EBAG9-overexpressing prostate cancer cells have a potential to facilitate immune escape of tumors by inhibiting T-cell cytotoxicity and modulating immune-related gene expression in T cells. Furthermore, we showed that a neutralizing antibody for EBAG9 could rescue the EV-mediated immune suppression by recovering T-cell cytotoxicity. In addition to its autocrine functions in cancer cells, EBAG9 could behave as a new class of immune checkpoint that suppresses tumor immunity in a secretory manner. We propose that EBAG9-targeting cancer treatment could be alternative therapeutic options for advanced diseases, particularly for those with EBAG9 overexpression.

EBAG9 modulates host immune defense against tumor formation and metastasis by regulating cytotoxic activity of T lymphocytes

Estrogen receptor-binding fragment-associated antigen 9 (EBAG9) is a primary estrogen-responsive gene that we previously identified in MCF-7 breast cancer cells using the CpG genomic binding-site cloning technique. The expression of EBAG9 protein is often upregulated in malignant tumors, suggesting that this protein is involved in cancer pathophysiology. In the present study, we investigated the role of EBAG9 in host defense against implanted tumors in Ebag9-knockout (Ebag9KO) mice. MB-49 mouse bladder cancer cells were subcutaneously implanted into Ebag9KO and control mice. We found that tumor formation and metastasis to the lung by MB-49 cells were substantially reduced in Ebag9KO mice compared with control mice. The infiltration of CD8⁺, CD3⁺ and CD4⁺ T cells into the generated tumors was enhanced in Ebag9KO mice compared with controls. Notably, CD8⁺ T cells isolated from tumors in Ebag9KO mice exhibited substantial upregulation of immunity- and chemoattraction-related genes, including interleukin-10 receptor, interferon gamma, granzyme A, granzyme B and chemokine (C-X-C motif) receptor 3 compared with CD8⁺ T cells from tumors in control mice. The CD8⁺ T cells isolated from tumors in Ebag9KO mice also exhibited enhanced degranulation and increased cytolytic activity. Furthermore, the adoptive transfer of CD8⁺ T cells isolated from tumors in Ebag9KO host could repress tumor growth by MB-49 cells implanted in wild-type host. These results suggest that EBAG9 modulates tumor growth and metastasis by negatively regulating the adaptive immune response in host defense. EBAG9 could be a potential target for tumor immunotherapy.

The role of RCAS1 as a biomarker in diagnosing CRC and monitoring tumor recurrence and metastasis

Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) plays an important role in tumor progression by helping tumor cell to escape from host immunological surveillance or modifying the characteristics of connective tissue around. RCAS1 may appropriately reflect the development and prognosis of tumor. In the study, we sought to identify the clinical significance of RCAS1 in colorectal cancer (CRC) diagnosis and tumor recurrence monitoring. Immunohistochemistry (IHC) with tissue array slides was preformed to analyze RCAS1 protein expression in CRC, colorectal polyps, and normal colon tissues. RCAS1 levels in colorectal cancer were significantly higher than those in colorectal polyps and normal colon tissues (P<0.001). Silencing RCAS1 gene in human colonic adenocarcinoma cells decreased cell proliferation and enhanced apoptosis through the p53 signaling pathway. Further analysis by an enzyme-linked immunosorbent assay (ELISA) showed that serum RCAS1 levels in CRC are significantly higher than in healthy controls and polyps (P<0.05), in which the highest serum RCAS1 level is reported in the recurrence group. The serum RCAS1 levels have a significant correlation with clinical stage and pathologic grading. Furthermore, the positive rate of serum RCAS1 in CRC was 82.1 %, which was higher than carcinoembryonic antigen (CEA). Especially in CEA-negative cases, the sensitivity of RCAS1 was 88.2 %. Finally, CRC patients who were followed up showed a serum RCAS1 level which significantly decreased after surgery (P<0.001) and obviously increased in the recurrence group. Taken together, our data demonstrated that RCAS1 is not only a supplementary serological biomarker for CRC diagnosis but also useful for monitoring tumor recurrence. RCAS1 might be a supplementary serological marker for CRC.

Association of positive EBAG9 immunoreactivity with unfavorable prognosis in breast cancer patients treated with tamoxifen

INTRODUCTION

Breast cancer is primarily a hormone-dependent tumor that is regulated by the status of the estrogen and progesterone receptors. We previously identified EBAG9 as an estrogen-responsive gene in MCF-7 human breast carcinoma cells. Upregulation of EBAG9 expression has been observed in several malignant tumors such as advanced breast cancers, indicating that EBAG9 might contribute to tumor progression.

PATIENTS AND METHODS

In the present study, we generated a monoclonal antibody against EBAG9, and then performed immunohistochemical analysis of EBAG9 expression in specimens obtained from breast cancer patients treated with tamoxifen as an adjuvant therapy.

RESULTS

EBAG9 immunoreactivity was detected in the cytoplasm of breast cancer cells and was significantly elevated in breast cancer samples from patients who relapsed during or after adjuvant tamoxifen treatment. Positive EBAG9 immunoreactivity was significantly correlated with poor patient prognosis.

CONCLUSION

These results suggest that EBAG9 expression in tumor regions is associated with an unfavorable prognosis in breast cancer patients treated with tamoxifen.

The membrane molecule RCAS1 induces immune cell apoptosis via the RCAS1-RCAS1R pathway

Tumor-associated antigen receptor-binding cancer antigen expressed on SiSo cells (RCAS1) has been identified as an estrogen-responsive gene and reportedly acts as a ligand for a putative receptor present in a variety of human cell lines and peripheral lymphocytes, thus leading them to apoptosis. In this study, we investigated the biological function of RCAS1 in vitro in inducing the apoptosis of immune cells. We detected the expression of the RCAS1 receptor (RCAS1R) in the cell lines, and investigated the mechanisms behind the apoptosis induced by RCAS1. HeLa cells were transfected with recombinant adenovirus Ad-RCAS1. RCAS1 induced the apoptosis of activated T cells, K562 cells and phytohemagglutinin (PHA)-activated Jurkat cells via the RCAS1-RCAS1R pathway. The expression of RCAS1R was induced. The intracellular overexpression of RCAS1 inhibited the growth of Jurkat and K562 cells. The expression of RCAS1 negatively correlated with the expression of glycogen synthase kinase 3β (GSK3β), but positively correlated with the expression of phosphorylated GSK3β (phGSK3β). RCAS1 expression was identified as a brown staining pattern in the breast cancer specimens. These findings may provide insight into the mechanisms through which tumor cells escape from immune surveillance.

EBAG9 inducing hyporesponsiveness of T cells promotes tumor growth and metastasis in 4T1 murine mammary carcinoma

The estrogen receptor-binding fragment-associated gene 9 (EBAG9) has been identified as an estrogen-responsive gene and was recently identified as a tumor-promoting and prognostic factor for renal cell carcinoma. We investigated whether EBAG9 expression was correlated with primary tumor growth and distant tumor metastasis in a murine breast carcinoma model. Knockdown expression of EBAG9 by small interfering RNA significantly suppressed tumor growth and metastasis in vivo in a highly malignant, spontaneously metastasizing 4T1 mouse mammary carcinoma model. 4T1 cells stably overexpressing EBAG9 developed larger and faster tumor growth and lung metastasis compared with parental 4T1 or 4T1 expressing vector alone. Strong specific cytotoxic T lymphocyte activity and enhanced gamma-interferon and interleukin-2 productions were induced in mice that received EBAG9 small interfering RNA therapy. Gene silencing of EBAG9 prolonged the survival of tumor-bearing mice and induced more intensive infiltration of CD8+ T cells in tumor mass. EBAG9 induced apoptosis of T cells, enhanced glycogen synthase kinase 3beta phosphorylation and inhibited gamma-interferon production of T cells when T lymphocytes were cocultured with 4T1 cells overexpressing EBAG9. Furthermore, overexpression of EBAG9 in 4T1 cells was accompanied with enhanced expression of chemokine (C-X-C motif) receptor 4, which might be involved in tumor metastasis. Taken together, our results suggested that EBAG9 promoted primary 4T1 mammary carcinoma growth and distant metastasis, and EBAG9 small interfering RNA exerted overt regression of tumor growth and metastasis. These findings might provide insights into the mechanism through which tumors evade immunosurveillance and provide a strategy for therapeutic intervention of cancer metastases.

Estrogen receptor-binding fragment-associated gene 9 expression and its clinical significance in human testicular cancer

OBJECTIVES

We previously demonstrated that estrogen receptor-binding fragment-associated gene 9 (EBAG9) is a tumor promoting factor in renal cell carcinoma (Ogushi T, Cancer Res. 2005; 65: 3700). Here, we evaluated EBAG9 expression and its clinical significance in normal and malignant human testicular tissues.

METHODS

We investigated the expression of EBAG9 in 90 testicular specimens (28 benign testicular tissue and 62 testicular germ cell tumor samples) by immunohistochemistry using rabbit polyclonal anti-EBAG9 antibody.

RESULTS

Positive immunostaining of EBAG9 in the cytoplasm was found in 32 (52%) cancerous lesions, whereas the immunoreactivity of EBAG9 was weak in benign testicular tissues. Serum lactate dehydrogenaze (LDH) level was significantly higher in EBAG9-positive cases (715.0 +/- 727.3) compared with the negative cases (221.4 +/- 126.8) (P = 0.0016). The EBAG9-positive cases among the patients with advanced clinical stage (Stage II and III) more frequently belonged to the intermediate or poor risk group in the International Germ Cell Consensus Prognostic Classification System (IGCCPCS), compared with the EBAG9-negative cases (P = 0.0012).

CONCLUSIONS

These findings suggest that increased expression of EBAG9 may play a significant role in cancer progression and aggressiveness in testicular germ cell tumors.

Prognostic molecular markers in hepatocellular carcinoma: a systematic review

Hepatocellular carcinoma (HCC) is the fifth commonest malignancy worldwide and its incidence is rising. Surgery, including transplantation, remains the only potentially curative modality for HCC, yet recurrence rates are high and long-term survival poor. The ability to predict individual recurrence risk and subsequently prognosis would help guide surgical and chemotherapeutic treatment. As understanding of hepatocarcinogenesis has increased, the myriad of genetic and molecular events that drive the hepatocarcinogenic disease process, including angiogenesis, invasion and metastasis, have been identified. This systematic review examines the evidence from published manuscripts reporting the prognostic potential of molecular biomarkers in hepatocellular carcinoma. In summary, a number of molecular biomarkers with prognostic significance have been identified in hepatocellular carcinoma. Not only might these molecules allow more accurate prediction of prognosis for patients with HCC, but they may also provide targets for potential therapeutic agents.

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Expression of RCAS1 in Female Genital Organs

Receptor-binding antigen expressed on a human uterine adenocarcinoma cell line, SiSo (RCAS1), has been reported to be a prognostic factor of various malignant tumors, and it has also been proven to induce apoptosis of lymphoid cells. However, its normal distribution and function have not yet been elucidated. The purpose of this study was to disclose the distribution of RCAS1 expression in normal female genital organs. Immunohistochemical staining using anti-RCAS1 and anti-MIB-1 antibodies was performed on 123 surgical specimens of a histologically normal uterus, ovary, or fallopian tube from 66 patients, and the apoptotic index was determined. In uterine cervical glands, the expression of RCAS1 was seen in 93% of the cases, and it was mainly localized in the superficial cervical glands. Near the areas of squamous metaplasia, RCAS1 was strongly expressed in all samples. In the uterine cervical squamous epithelium, RCAS1 was seen in 84% of cases. In the uterine corpus, RCAS1 was seen in 87% of all cases, and it was mainly expressed in the endometrial glands of basalis layer. There was significant positive correlation between age and RCAS1 expression, but no significant difference was found regarding the endometrial status and RCAS1 expression in endometrium. No significant correlation was found between RCAS1 expression and MIB-1 index/apoptotic index. RCAS1 may affect these metaplastic processes and tumor progression.

Significance of RCAS1 antigen in hepatocellular, cholangiocellular and pancreatic carcinomas

Since receptor-binding cancer antigen expressed on SiSo cells (RCAS1) was first reported as a tumor-associated antigen of gynecologic cancer, its function and practical value as a tumor marker have been investigated in various types of carcinomas. Basic research has indicated that RCAS1 expression in cancer cells contributes to the evasion from immune surveillance and progression of carcinomas. The clinical significance of RCAS1 expression in hepatobiliary and pancreatic carcinomas has also been investigated. In this review, we summarize the clinical application of RCAS1 antigen in hepatic and pancreaticobiliary diseases. We present new data and review current knowledge about the potential of RCAS1 as a tumor marker and the relationship between RCAS1 expression and clinicopathologic parameters. We found that the clinical function of RCAS1 appeared to differ according to the type of carcinoma. In hepatocellular carcinoma, the clinical significance of histological RCAS1 expression was controversial and that of serum RCAS1 levels showed little clinical value. In pancreaticobiliary cancers, high RCAS1 expression in tissue samples was an unfavorable independent prognostic factor. Serum RCAS1 was a superior tumor marker reflecting the disease activity in biliary carcinoma. In pancreatic cancer, serum RCAS1 levels were less useful than in biliary carcinoma but may be available for genetically CA19-9-negative patients and for CA19-9-non-producing cancer. This review also offers suggestions for future studies.

Estrogen receptor-binding fragment-associated antigen 9 is a tumor-promoting and prognostic factor for renal cell carcinoma

The estrogen receptor-binding fragment-associated antigen 9 (EBAG9) has been identified as a primary estrogen-responsive gene in human breast cancer MCF7 cells. A high expression of EBAG9 has been observed in invasive breast cancer and advanced prostate cancer, suggesting a tumor-promoting role of the protein in malignancies. Here we show that intratumoral (i.t.) administration of small interfering RNA against EBAG9 exerted overt regression of tumors following s.c. implantation of murine renal cell carcinoma (RCC) Renca cells. Overexpression of EBAG9 did not promote the proliferation of culture Renca cells; however, the inoculated Renca cells harboring EBAG9 (Renca-EBAG9) in BALB/c mice grew faster and developed larger tumors compared with Renca cells expressing vector alone (Renca-vector). After renal subcapsular implantation, Renca-EBAG9 tumors significantly enlarged compared with Renca-vector tumors in BALB/c mice, whereas both Renca-EBAG9 and Renca-vector tumors were developed with similar volumes in BALB/c nude mice. No apparent difference was observed in specific cytotoxic T-cell responses against Renca-EBAG9 and Renca-vector cells; nonetheless, the number of infiltrating CD8+ T lymphocytes was decreased in Renca-EBAG9 subcapsular tumors. Furthermore, immunohistochemical study of EBAG9 in 78 human RCC specimens showed that intense and diffuse cytoplasmic immunostaining was observed in 87% of the cases and positive EBAG9 immunoreactivity was closely correlated with poor prognosis of the patients. Multivariate analysis revealed that high EBAG9 expression was an independent prognostic predictor for disease-specific survival (P = 0.0485). Our results suggest that EBAG9 is a crucial regulator of tumor progression and a potential prognostic marker for RCC.

Reevaluation of the 22-1-1 antibody and its putative antigen, EBAG9/RCAS1, as a tumor marker

Background

Tumor-associated antigens are appreciated as diagnostic markers, but they have also prompted tremendous efforts to develop tumor-specific immunotherapy. A previously cloned tumor-associated antigen, EBAG9, was initially defined by reactivity with the monoclonal antibody 22-1-1. Functionally, the EBAG9-encoded gene-product was believed to induce apoptosis in activated immune cells. However, using a cell-biological approach we identified EBAG9 as a Golgi-resident modulator of O-linked glycan expression, the latter product was then recognized by the 22-1-1 antibody. Secondly, EBAG9 expression was found physiologically in all murine tissues examined. This raised the question if EBAG9 is tumor-specific and mediates apoptosis itself or through O-linked glycans generated, among them the cognate 22-1-1 antigen Tn.

Methods

We have used immunohistochemistry to detect the expression of 22-1-1 and EBAG9 in various tissues. Correlation between expression of both antigens in cell lines was analysed by immunoblot and flow cytometry. Apoptosis was studied by using flow cytometry and Caspase-Glo™ 3/7 assay kit. Cellular distribution of EBAG9 was analysed by electron and confocal microscopy.

Results

Here, we compared expression of the 22-1-1 and EBAG9-defined antigens in normal and neoplastic tissues in situ. In contrast to 22-1-1 staining, EBAG9 is a ubiquitously expressed antigen in all normal and cancerous tissues. Functional studies on the role of 22-1-1 reactive material did not support any evidence for apoptosis induction. Employing electron and confocal microscopy, a refined subcellular localization of EBAG9 at the Golgi was obtained.

Conclusion

We suggest that the estrogen-inducible EBAG9 gene-product and the 22-1-1 defined antigen are structurally and functionally separate antigens.

p62 expression in primary carcinomas of the digestive system

AIM: To characterize p62 expression and define the relationship between p62 expression and cell proliferation in primary carcinomas of the digestive system.

METHODS: p62 expression was characterized in surgically resected tumor specimens from 60 patients with primary carcinomas of the digestive tract (including 22 esophageal carcinomas, 17 gastric carcinomas, and 21 colorectal carcinomas) and 40 patients with hepatocellular carcinoma (HCC) by immunohistochemistry (IHC). The cell proliferation was determined by IHC of Ki-67 in 40 patients with HCC.

RESULTS: Twenty-two cases of esophageal carcinoma were histopathologically diagnosed as squamous cell carcinoma. We combined the gastric and colorectal carcinomas based on the equivalent histology. The 38 tumors in the combined groups, consisted of 17 well-differentiated, eight moderately differentiated, nine poorly differentiated carcinomas, and four mucinous adenocarcinomas. According to the criteria of Edmondson and Steiner, 40 patients with HCC were graded (2 grade I, 17 grade II and 21 grade III). p62 expression in primary carcinomas of the gastrointestinal tract (60/60,100%) was higher than that (27/40, 67.5%) of HCC (P<0.01, χ² = 19.63). High expression levels of p62 were positively correlated with histological grades in gastric and colorectal carcinomas (P<0.0001) and inversely associated with those in HCC (P = 0.0322). No significant correlations were observed for esophageal carcinomas (P = 0.8246). p62 expression was also detected in the cytoplasm of morphologically normal columnar epithelial cells adjacent to the cancer foci of gastric and colorectal carcinomas. In 40 HCC specimens, the mean Ki-67 labeling index (LI) was (19.6±16.0)%. It was (28.3±18.73)% in 12 cases with high p62 expression (+++), (7.53±14.83)% in 13 cases without p62 expression(-). Patients with a high p62 expression showed a significantly higher level of Ki-67 staining than those without p62 expression (P<0.05, t = 2.069).

CONCLUSION: p62 expression is common in carcinomas of the digestive system and higher in carcinomas of the gastrointestinal tract than in primary HCC. p62 is a cellular differentiation-related protein. Cancer cells with a high p62 expression exhibited highgrowth fractions in HCC.

Expression of RCAS1 in esophageal squamous cell carcinoma is associated with a poor prognosis

BACKGROUND

Receptor-binding cancer antigen expressed on SiSO cells (RCAS1) has been reported to act as a ligand for a receptor present on normal peripheral lymphocytes and to induce apoptotic cell death. We aimed to elucidate the significance of RCAS1 expression in human esophageal squamous cell carcinomas (ESCC).

METHODS

RCAS1 expression was examined immunohistochemically in surgically resected esophageal carcinoma tissues from 114 patients. We also examined the relationships between RCAS1 expressions, the tumor Ki-67 indices (a marker of proliferation), and the number of CD8+ tumor-infiltrating lymphocytes (TILs).

RESULTS

RCAS1 immunoreactivity was detected in the membranes and cytoplasm of the tumor cells. Of the 114 esophageal carcinomas, 39 (34.2%) were strongly positive for RCAS1 immunostaining on the membranes of the cancer cells, 41 (36.0%) were weakly positive, and 34 (29.8%) were negative. A comparison of RCAS1 expression and clinicopathological characteristics in all 114 patients revealed significant associations between RCAS1 expression and lymph node status (P < 0.05), and pathologic stage (P < 0.05). The survival rates of patients with RCAS1-negative tumors were significantly higher than those of patients with both RCAS1-weak positive tumors and RCAS1-strong positive ones (log-rank P < 0.05). Multivariate analysis revealed that RCAS1 positivity was an independent prognostic factor (P < 0.05). The relationship between RCAS1 expression and the numbers of CD8+ T-cells in the primary tumors revealed that RCAS1-negative tumors tended to contain more of these cells than both RCAS1-weak positive tumors and RCAS1-strong positive ones (P = 0.2495).

CONCLUSIONS

RCAS1 may play a significant role in tumor progression via an immune escape mechanism; thus, RCAS1 expression could be used as a predictor of poor prognosis in patients with ESCC.

Expression of a tumor-associated antigen, RCAS1, in canine mammary tumors

Receptor-binding cancer antigen expressed on SiSo cells (RCAS1), one of novel cancer cell-surface antigens, is strongly expressed in invasive cancers. RCAS1 inhibits the in vitro growth of lymphocytes such as T cells and natural killer (NK) cells, and induces apoptotic cell death. We investigated the expression of RCAS1 in canine mammary tumor cell lines and tumor cells by immunohistochemistry, and also in situ deoxyribonucleic acid (DNA) fragmentation in tumor-infiltrating lymphocytes (TILs) by the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling (TUNEL) method. All canine mammary tumor cell lines expressed RCAS1 at both the messenger ribonucleic acid (mRNA) and protein level. Immunohistochemically, RCAS1 was negative in 100% of normal mammary glands, but was expressed in 100% of malignant tumors examined. In most malignant mammary tumors, RCAS1 was localized in the cytoplasm with no polarity of expression. In benign mammary tumors, it was detected on the luminal surface of the tumor cell. RCAS1 expression or localization was significantly correlated with malignancy. In situ DNA fragmentation of CD3-positive TILs was observed in RCAS1-expressing tumors. RCAS1-expressing tumors, indicating a possible induction of apoptotic cell death in TILs through RCAS1 expression. These observations suggest that RCAS1 probably plays an important role in tumor progression and escape from immune surveillance in canine mammary tumors.

Effect of c-myc, Ki-67, MMP-2 and VEGF expression on prognosis of hepatocellular carcinoma patients undergoing tumor resection

AIM: To explore the effect of c-myc, Ki-67, MMP-2 and VEGF expression on prognosis of hepatocellular carcinoma (HCC) patients undergoing tumor resection.

METHODS: Primary HCC patients underwent tumor resection were retrospectively analysed. The maximum size of the tumor was less than 5 cm, there was only one nodule in each patient. No chemoembolization was performed before resection. They were followed up after resection, and the time of recurrence was recorded. They were divided into 2 groups: group A (15 cases): tumor recurrence within 1 year after tumor resection, and group B (15 cases): with or without tumor recurrence 2 years after tumor resection. Pathological slices were made with tumor wax-sample. Immunohistochemistry staining was performed with c-myc, Ki-67, MMP-2 and VEGF monoclonal antibodies. Staining intensity was quantitatively analysed with a pathological diagram-writing analyzing system. The expressing intensity differences of stained molecules in cancer tissue and para-cancer were analysed.

RESULTS: c-myc, Ki-67, MMP-2 and VEGF expressing intensities in cancer tissue in group A were higher than those in group B (P values were 0.010, 0.030, 0.022 and 0.004, respectively), but they were not significantly different in para-cancer tissue in groups A and B (P values were 0.334, 0.343, 0.334 and 0.334, respectively).

CONCLUSION: The expression of c-myc, Ki-67, MMP-2 and VEGF in cancer tissue is related to the recurrence of HCC after tumor resection.