一种改进的Western杂交方法

Western杂交是一种检测蛋白质的免疫化学方法,已在生物科学的许多领域得到广泛应用,但以前的文献介绍的Western杂交程序过于繁琐。本文根据Western杂交的基本原理结合已报道资料进行了一些改进,并应用到猪血清瘦素蛋白的检测。该程序简单易操作,结果清晰,证明改进后的方法完全可行。

谷物中A类单端孢霉烯族真菌毒素检测方法研究进展

概述谷物中A类单端孢霉烯族真菌毒素的检测方法。描述目前最常见的A类单端孢霉烯族真菌毒素 (HT 2和T 2毒素 )的筛选和定量方法。其中包括各种现行的提取、纯化措施和色谱方法 (HPLC、GC) ,及免疫化学方法 ,特别是酶联免疫吸附测定法 (ELISA)。通过对这些方法的相互比较发现 ,到目前为止 ,可以认为ELISA是一种简单、快速。

抗人PCIA1单克隆抗体的制备及其生物特征的研究

目的:筛选制备抗人PCIA1的单克隆抗体,鉴定其生物学特征。方法:采用原核表达并纯化的PCIA1蛋白作为抗原,采用杂交瘤技术制备抗人PCIA1单克隆抗体的杂交瘤,用ELISA进行筛选和鉴定其亚类,并用细胞扒片免疫化学方法检测其反应性。结果:获得了32株分泌抗人PCIA1的McAb杂交瘤细胞,McAb-1A4的染色体呈双亲特点,该McAb与多种人肿瘤细胞株和正常肝细胞株有反应。结论:McAb-1A4可用于PCIA1的细胞内定位研究。

Expression of HMGB1 Protein in Human Cervical Squamous Epithelium Carcinoma

OBJECTIVE To investigate the expression of the high mobility group boxl（HMGB1） in human cervical squamous epithelial carcinoma （CSEC） and to explore the relationship of HMGB1 expression to the differentiation degree, size, invasion and metastasis of CSEC. METHODS Immunohistochemical staining of tissue microarrays and Western blot analysis were conducted to detect the expression of HMGB1 in the following tissue samples： 30 carcinoma in situ, 90 invasive CSEC without metastasis, 30 invasive CSEC with metastasis, 30 cases of normal cervical squamous epithelia. RESULTS The positive-expression rate of HMGB1 was 58.7% （88/150） in CSEC, showing a significant difference compared to normal cervical squamous epithelia. The expression of HMGB1 was correlated with tumor size, invasion and metastasis of CSEC （respectively, P〈0.01）, but had no relationship with the degree of differentiation （P〉0.05）. CONCLUSION The over-expression of HMGB1 in CSEC might be a useful parameter as an indication of tumor invasion, metastasis, prognosis and overall biological behavior of human CSEC, as well as a noval target site for gene therapy.

Interleukin-8, a promising predictor for prognosis of pancreatic cancer

AIM: To investigate the value of interleukin-8 (IL-8), a pro-inflammatory chemokine, in predicting the prognosis of pancreatic cancer. METHODS: Expression of IL-8 and its receptor CXCR1 was assessed by immunohistochemistry in pancreatic cancer and chronic pancreatitis samples. Enzyme-linked immunosorbent assay was used to detect the serum IL-8 levels in pancreatic cancer patients. Human pancreatic cancer tissues were heterotopically transplanted to the immune-deficiency mice to evaluate the effect of serum IL-8 on the tumorigenesis of the cancer samples.RESULTS: IL-8 and CXCR1 proteins were both overexpressed in pancreatic adenocarcinoma samples (55.6% and 65.4%, respectively) compared with the matched para-cancer tissues (25.9% and 12.3%, P < 0.01), or chronic pancreatitis (0% and 25%, P < 0.05). Serum IL-8 levels in pancreatic cancer patients (271.1 ± 187.7 ng/mL) were higher than in other digestive system tumors, such as gastric cancer (41.77 ± 9.11 ng/mL, P = 0.025), colorectal carcinoma (78.72 ± 80.60 ng/mL, P = 0.032) and hepatocellular carcinoma (59.60 ± 19.80 ng/mL, P = 0.016). In vivo tumorigenesis analysis further proved that tumor tissues from patients with higher serum IL-8 levels grew faster than those with lower IL-8 levels. CONCLUSION: IL-8 can be a fine serum marker for predicting the prognosis pancreatic cancer.

Inhibition of high-mobility group box 1 expression by siRNA in rat hepatic stellate cells

AIM:To explore the role of high-mobility group box 1 (HMGB1) protein during liver fibrogenesis and investigate the functional effects of HMGB1 gene silencing in hepatic stellate cells (HSCs) using siRNA.METHODS:Hepatic fibrosis in rats was induced through serial subcutaneous injections of dimethylnitrosamine,and expression of HMGB1 was detected by immunohistochemistry.HMGB1 siRNAs were developed and transiently transfected into HSC-T6 cells using Lipofectamine 2000.HMGB1 expression was evaluated by real-time polymerase chain reaction (PCR) and Western blotting analysis.Expression of α-smooth muscle actin (α-SMA) and collagen typesⅠand Ⅲ was evaluated by real-time PCR.Cell proliferation and the cell cycle were determined using the methyl thiazolyl tetrazolium method.Finally,collagen content in HSC supernatant was evaluated by an enzyme-linked immunosorbent assay.RESULTS:The results showed that HMGB1 was upregulated during liver fibrosis and that its expression was closely correlated with the deposition of collagen.siRNA molecules were successfully transfected into HSCs and induced inhibition of HMGB1 expression in a time-dependent manner.Moreover,HMGB1 siRNA treatment inhibited synthesis of α-SMA and collagen types Ⅰ and Ⅲ in transfected HSCs.CONCLUSION:This study suggests a significant functional role for HMGB1 in the development of liver fibrosis.It also demonstrates that downregulation of HMGB1 expression might be a potential strategy to treat liver fibrosis.

Metastasis-associated protein 1 induces VEGF-C and facilitates lymphangiogenesis in colorectal cancer

AIM:To study the correlation between high metastasisassociated protein 1(MTA1)expression and lymphangiogenesis in colorectal cancer(CRC)and its role in production of vascular endothelial growth factor-C(VEGF-C). METHODS:Impact of high MTA1 and VEGF-C expression levels on disease progression and lymphovasculardensity(LVD,D2-40-immunolabeled)in 81 cases of human CRC was evaluated by immunohistochemistry. VEGF-C mRNA and protein expressions in human LoVo and HCT116 cell lines were detected by real-time polymerase chain reaction and Western blotting,respectively,with a stable expression vector or siRNA. RESULTS:The elevated MTA1 and VEGF-C expression levels were correlated with lymph node metastasis and Dukes stages(P<0.05).Additionally,high MTA1 expression level was correlated with a large tumor size(P< 0.05).A significant correlation was found between MTA1 and VEGF-C protein expressions in tumor cells(r=0.371, P<0.05).Similar to the VEGF-C expression level,high MTA1 expression level was correlated with high LVD in CRC(P<0.05).Furthermore,over-expression of MTA1 significantly enhanced the VEGF-C mRNA and protein expression levels,whereas siRNAs-knocked down MTA1 decreased the VEGF-C expression level. CONCLUSION:MTA1,as a regulator of tumor-associated lymphangiogenesis,promotes lymphangiogenesis in CRC by mediating the VEGF-C expression.

Intraductal neoplasm of the intrahepatic bile duct: Clinicopathological study of 24 cases

AIM: To investigate the clinicopathological features of intraductal neoplasm of the intrahepatic bile duct (INihB). METHODS: Clinicopathological features of 24 cases of INihB, which were previously diagnosed as biliary papillomatosis or intraductal growth of intrahepatic biliary neoplasm, were reviewed. Mucin immunohistochemistry was performed for mucin (MUC)1, MUC2, MUC5AC and MUC6. Ki-67, P53 and β-catenin immunoreactivity were also examined. We categorized each tumor as adenoma (low grade), borderline (intermediate grade), and malignant (carcinoma in situ , high grade including tumors with microinvasion). RESULTS: Among 24 cases of INihB, we identified 24 tumors. Twenty of 24 tumors (83%) were composed of a papillary structure; the same feature observed in intraductal papillary neoplasm of the bile duct (IPNB). In contrast, the remaining four tumors (17%) showed both tubular and papillary structures. In three of the four tumors (75%), macroscopic mucin secretion was limited but microscopic intracellular mucin was evident. Histologically, 16 tumors (67%) were malignant, three (12%) were borderline, and five (21%) were adenoma. Microinvasion was found in four cases (17%). Immunohistochemical analysis revealed that MUC1 was not expressed in the borderline/adenoma group but was expressed only in malignant lesions (P = 0.0095). Ki-67 labeling index (LI) was significantly higher in the malignant group than in the borderline/adenoma group (22.2 ± 15.5 vs 7.5 ± 6.3, P < 0.01). In the 16 malignant cases, expression of MUC5AC showed borderline significant association with high Ki-67 LI (P = 0.0622). Nuclear expression of β-catenin was observed in two (8%) of the 24 tumors, and these two tumors also showed MUC1 expression. P53 was negative in all tumors. CONCLUSION: Some cases of INihB have a tubular structure, and are subcategorized as IPNB with tubular structure. MUC1 expression in INihB correlates positively with degree of malignancy.

Oxidative stress and hypoxia-induced factor 1α expression in gastric ischemia

AIM:To investigate the relation of reactive oxygen species (ROS) to hypoxia induced factor 1α (HIF-1α) in gastric ischemia. METHODS:The animal model of gastric ischemia reperfusion was established by placing an elastic rubber band on the proximal part of the bilateral lower limb for ligature for 3 h and reperfusion for 0,1,3,6,12 or 24 h. Ischemic post-conditioning,three cycles of 30-s reperfusion and 30-s femoral aortic reocclusion were conducted before reperfusion. Histological and immunohistochemical methods were used to assess the gastric oxidative damage and the expression of HIF1-α in gastric ischemia. The malondialdehyde (MDA) content and superoxide dismutase (SOD),xanthine oxidase (XOD) and myeloperoxidase (MPO) activities were determined by colorimetric assays. RESULTS:Ischemic post-conditioning can reduce post-ischemic oxidative stress and the expression of HIF-1α of gastric tissue resulting from limb ischemia reperfusion injury. MDA,SOD,XOD and MPO were regarded as indexes for mucosal injuries from ROS,and ROS was found to affect the expression of HIF-1α under gastric ischemic conditions. CONCLUSION:ROS affects HIF-1α expression under gastric ischemic conditions induced by limb ischemia reperfusion injury. Therefore,ROS can regulate HIF-1α expression in gastric ischemia.

Clinicopathological significance of B-cell-specific Moloney murine leukemia virus insertion site 1 expression in gastric carcinoma and its precancerous lesion

AIM： To explore the relation between B-cell-specific Moloney murine leukemia virus insertion site 1 （Bmi-1） expression and the clinicopathological features of gastric carcinoma （GC）.METHODS： Immunohistochemistry was used to detect the expression of Bmi-1 and ki-67. Doublelabeling staining was used to display the distribution of Bcl-2^＋/ki-67 cells in 162 cases of GC and its matched normal mucosa and precancerous lesion.RESULTS： The positive rate of Bmi-1 expression in GC（52.5%） was significantly higher than that in normal gastric mucosa （21.6%, X^2 = 33.088, P 〈 0.05）. The Bmi-1 expression in GC was closely related with the Lauren＇s and Borrmann＇s classification and clinicalstage （X^2 = 4.400, 6.122 and 11.190, respectively, P〈 0.05）. The expression of ki-67 was related to the Borrmann＇s classification （X^2 = 13.380, P 〈 0.05）.Bcl-2 expression was correlated with the Lauren＇s classification （Z2 = 4.725, P 〈 0.05）, and the Bmi-1 expression both in GC （rk = 0.157, P 〈 0.05） and inintestinal metaplasia （rk = 0.270, P 〈 0.05）.CONCLUSION： Abnormal Bmi-1 expression in GCmay be involved in cell proliferation, apoptosis andcancerization. This marker can objectively indicate theclinicopathological characteristics of GC.

Reduced Popdc3 expression correlates with high risk and poor survival in patients with gastric cancer

AIM： To investigate the expression of Popeye domain containing 3 （Popdc3） and its correlation with clinicopathological features and prognosis of gastric cancer.METHODS： The method of immunohistochemistry was used to investigate the expression of Popdc3 in 306 cases of human gastric cancer and 84 noncancerous gastric tissues. Simultaneously, the relationship between Popdc3 expression and the survival of the patients was retrospectively analyzed.RESULTS： Popdc3 was detected in 72 （85.71%） of 84 human nontumor mucosa. High expression of Popdc3protein was detected in 78 （25.49%） of 306 human gastric cancer cases, and low expression was detected in 228 （74.51%）. Low expression of Popdc3 correlated with depth of invasion （P 〈 0.0001）, regional lymph nodes （P 〈 0.0001） and distant metastasis （P =0.02）, and tumor, nodes, metastasis （TNM） stages （P 〈 0.0001）. On multivariate analysis, only the patient＇s gender, regional lymph node metastasis, distant metastasis, TNM stages, and the expression of Popdc3 were independent prognostic factors in patients with gastric cancer. The Kaplan-Meier plot showed that low Popdc3 expression had a much more significant effect on the survival of those patients with early-stage tumors X^2 = 104.741, P 〈 0.0001）, with a 〉 51.9% reduction in the three-year survival compared with high Popdc3 expression. In late stages, the difference was also significant X^2 = 5.930, P = 0.015）, with a 32.6% reduction in the three-year survival.CONCLUSION： Reduced expression of Popdc3 may play a significant role in the carcinogenesis and progression of gastric cancer. Popdc3 may be an independent prognostic factor.

Expression of COX-2, PCNA, Ki-67 and p53 in gastrointestinal stromal tumors and its relationship with histopathological parameters

AIM: To investigate the expression of Cyclooxygenase-2 (COX-2), proliferating cell nuclear antigen (PCNA), Ki-67 and p53 in gastrointestinal stromal tumors (GISTs) and its relationship with histopathological parameters. METHODS: Twenty-five GISTs were examined by light microscopy and immunohistochemistry. c-kit, CD34, SMA, S-100 protein, COX-2, PCNA, Ki-67 and p53 were detected immunohistochemically and the relationship was evaluated among histopathologic parameters such as mitotic index (MI), tumor grade, tumor size, COX-2, PCNA, Ki-67 and p53. RESULTS: COX-2 protein expression was found in 19 of 25 (76%) of the tumors, and expression was noted in the cytoplasm of the tumor cells. p53 was significantly related to MI and tumor grade but no relationship was found between COX-2, proliferation markers and MI, tumor grade and tumor size. CONCLUSION: COX-2 is expressed in most GISTs and it may play an important role in the proliferation and progression of these tumors or a useful marker to identify GIST. Although immunohistochemical assessment of p53 can be used for distinguishing the risk groups of GISTs, tumor size and mitotic rate should be considered at the same time.

Value of COX-2 and HER-2 in Judging Condition and Prognosis in Non-Small Cell Lung Cancer Patients

OBJECTIVE To investigate the expressions of cyclooxygenase 2 （COX-2） and human epidermal growth factor receptor-2 （HER-2） in non-small cell lung cancer （NSCLC） and their clinical significance in identifying the progression and prognosis of the NSCLC patients. METHODS Immunohistochemical indirect method was used to detect the expressions of the COX-2 and HER-2 protein in 54 NSCLC specimens, 16 paraneoplastic specimens, and 10 normal tissue specimens. RESULTS The positive rates of COX-2 and HER-2 protein expressions were respectively 75.9% and 40.7% in the NSCLC specimens, 25% and 12.5% in the paraneoplastic specimens, and 0 in the normal tissue. The COX-2 protein expression in lung cancer （LC） was not only related to the smoking habit of the patients and histological grades of LC, but also to the TNM stages, and lymphatic metastasis （P 〈 0.05）. HER-2 protein expression closely correlated to the pathologic types, histological grades, TNM stages, and lymphatic metastasis （P 〈 0.05）. The result of univariate analysis showed that all the histological grades, TNM stages, lymphatic metastasis, and expressions of COX-2/HER-2 correlated to the prognosis of NSCLC patients （mean of P value 〈 0.01）. The multivariate survival analysis indicated that there were signi.cant di.erences in comparison of the survival time between the COX-2 （＋＋/＋＋＋） /HER-2 （＋＋/＋＋＋） and the COX-2 （-/＋）/HER-2 （-/＋） groups （P〈 0.001）, suggesting the COX-2/HER-2 was a negative prognostic factor. CONCLUSION COX-2 and HER-2 are valuable in identifying the progression of NSCLC and predicting the prognosis of NSCLC patients. COX-2 and HER-2 are useful for judging the NSCLC patient＇s condition, and are of great value to the decision of NSCLC prognosis.

Aberrant methylation of the 3q25 tumor suppressor gene PTX3 in human esophageal squamous cell carcinoma

AIM:To identify the novel methylation-silenced gene pentraxin 3(PTX3) in esophageal squamous cell carcinoma(ESCC).METHODS:PTX3 mRNA expression was examined in six human ESCC cell lines,one human immortalized normal esophageal epithelial cell line,primary ESCC tumor tissue,and paired adjacent nontumor tissue using reverse transcription polymerase chain reaction(RTPCR).Semi-quantitative immunohistochemistry was used to examine cellular localisation and protein levels.Methylation specific PCR and bisulphite genomic sequencing were employed to investigate the methylation of the candidate gene.RESULTS:In the majority of ESCC cell lines,we found that PTX3 expression was down-regulated due to gene promoter hypermethylation,which was further confirmed by bisulphite genomic sequencing.Demethylation treatment with 5-aza-2'-deoxycytidine restored PTX3 mRNA expression in ESCC cell lines.Methylation was more common in tumor tissues(85%) than in adjacent nontumor tissues(25%)(P < 0.01).CONCLUSION:PTX3 is down-regulated through promoter hypermethylation in ESCC,and could potentially serve as a biomarker of ESCC.

Prognostic Impact of Cell Division Cycle Associated 2 Expression on Pancreatic Ductal Adenocarcinoma

Objective To examine the expression of cell division cycle associated 2(CDCA 2) in pancreatic ductal adenocarcinoma(PDAC) and investigate its role in prognosis of PDAC patients.Methods This retrospective study included 155 PDAC patients who underwent surgical treatment and complete post-operative follow-up.Clinicopathologic data were collected through clinical database.Tissue microarray was constructed and immunohistochemistry was performed to detect CDCA2 expression in the PDAC tumor tissues and adjacent non-tumor tissues.Clinicopathological characteristics between high and low CDCA2 expression were compared.Correlation of CDCA2 expressions with patients' survival was analyzed using Kaplan-Meier method and Cox regression analysis.Results Expression of CDCA2 in PDAC cells was significantly higher than that in adjacent non-tumor tissues(U=4056.5,P<0.001).Univariate analysis showed that CDCA2 expression [hazard ratio(HR)=1.574,95% confidence interval(CI)=1.014-2.443,P=0.043] and node metastasis(HR=1.704,95%CI=1.183-2.454,P=0.004) were significantly associated with prognosis.Cox regression analysis showed CDCA2 expression was not an independent prognostic risk factor(HR=1.418,95%CI=0.897-2.242,P=0.135) for PDCA patients.Stratification survival analysis demonstrated CDCA2 expression as an independent prognostic risk factor in male patients(HR=2.554,95%CI=1.446-4.511,P=0.003) or in non-perineural invasion patients(HR=2.290,95%CI=1.146-4.577,P=0.012).Conclusions CDCA2 is highly expressed in PDAC tumor tissue.Although CDCA2 is not an independent prognostic risk factor for PDAC patients,it might be used to help predict prognosis of male or non-perineural invasion patients of PDAC.

The Significance of CXCR4 Expression for the Prediction of Lymph Node Metastasis in Breast Cancer Patients

OBJECTIVE The chemokine receptor(CXCR4)CXC chemokine receptor 4)plays an important role in cancer metastasis.We therefore studied differential expression of the CXCR4,as well as that of the biomarker HER2,so as to evaluate whether these biomarkers can be used to predict axillary lymph node metastasis in breast cancer patients. METHODS Immunohistochemistry was used to evaluate the CXCR4 and HER2 expressions and to examine the paraffin sections of the breast cancers at various stages.Positive lymph node expression was found in 80 of the cases,and in 7 there was negative expression. RESULTS Compared to the cases with negative lymph nodes, there was a high expression of CXCR4(26.3% vs.14.3%,P=0.013), and an over-expression of HER2(28.8% vs.14.3%,P=0.011). Moreover,there was a direct correlation between the CXCR4 and HER2 expressions and the tumor staging(P=0.000)and lymph node metastasis(P=0.032).When the two biomarkers,i.e.CXCR4 and HER2,were concurrently labeled,a high expression of one of the biomarkers could be seen in the cases with positive lymph nodes(51.3% vs.28.6%,P<0.003). CONCLUSION The chemokine receptor,CXCR4,is a new-type biomarker in predicting axillary lymph-node metastasis in breast cancers.Compared with the other markers,such as HER2 etc., assessment of CXCR4 can improve the prediction of the presence and extent of lymph node involvement.

Expression of caveolin-1 in clear cell renal cell carcinoma and its correlation with microvessel density

Objective:The aim of the study was to investigate the clinicopathologic significance of caveolin-1 expression in clear cell renal cell carcinoma (CCRCC) and its correlation with microvessel density (MVD).Methods:The expression of caveolin-1 was detected by the immunohistochemistry method,while the microvessel density was detected by the immunohistochemistry expression of CD34.Results:In the CCRCCs,the positive rate of caveolin-1 was 67.4%,the over expression of caveolin-1 was not related with sex and age,but related with clinicopathologic parameter,such as tumor sizes,clinical TMN stage,nuclear stage and survival time (P < 0.05).The MVD of positive caveolin-1 cases was significantly higher than that without caveolin-1 expression (P < 0.05).Conclusion:The expression of caveolin-1 is helpful in the prognostic evaluation of CCRCCs and it may be involved in the tumor angiogenesis.

Clinical Significance of CENP-H Expression in Uterine Cervical Cancer

Objective This work aims to investigate the expression pattern and clinicopathologic significance of centromere protein H(CENP-H) in uterine cervical cancer(UCC). Methods The level of CENP-H expression in the paraffin sections of 62 UCC cases was determined by the SP immunohistochemical method,with complete clinicopathologic data in all cases.Statistical analysis was conducted to evaluate the prognostic and diagnostic significance of CENP-H using SPSS13.0 software package. Results Immunohistochemical assay showed strong CENP-H expression in 61.29% (38/62) of the paraffin-embedded cervical cancer tissues.Statistical analysis revealed a strong correlation between the CENP-H expression and the clinical classification(P=0.038) of the cervical carcinoma.The expression increased with rise of the stages.The analysis of Cox proportional hazards regression model suggested that CENP-H expression(P=0.002) and tumor stage(P=0.001) were independent prognostic markers for the survival of UCC patients.The survival analysis showed that the survival rate was significantly lower in patients with high expression of CENP-H than in those with low expression of CENP-H(P=0.001). Conclusions CENP-H is likely to be a valuable marker for carcinogenesis and progression of UCC.It might be used as the important diagnostic and prognostic marker for cervical carcinoma patients,especially for those at early stage.

Strong expression of CD133 is associated with increased cholangiocarcinoma progression

AIM:To determine the role of CD133 in cholangiocarcinoma progression. METHODS:CD133 protein expression was evaluated by immunohistochemistry in 34 cholangiocarcinoma specimens.In addition,proliferation,chemoresistance and invasive properties of CD133-enriched(CD133 + ) and CD133-depleted(CD133 )RMCCA1 cholangiocarcinoma cells were studied and compared. RESULTS:Strong CD133 expression was observed in 67.6%(23/34)of the cholangiocarcinoma specimens. Strong expression of CD133 was significantly associated with nodal metastasis(P=0.009)and positive surgical margin status(P=0.011).In the in vitro study, both the CD133 + and CD133 cells had similar proliferation abilities and resistance to chemotherapeutic drugs.However,the CD133 + cells had a higher invasive ability compared with CD133 cells. CONCLUSION:CD133+cells play an important role in the invasiveness of cholangiocarcinoma.Targeting of the CD133+cells may be a useful approach to improve treatment against cholangiocarcinoma.

Expression and clinical significance of PTEN protein in osteosarcoma

Objective： To investigate the expression and significance of cancer inhibitory gene PTEN protein in osteosar-coma. To analyze the level of its expression in different histological classification of osteosarcoma. To determine the possibility of taking PTEN protein as a marker gene for diagnosing osteosarcoma. To observe the clinical value of PTEN expression levels as a reference index for osteosarcoma classification. Methods： 43 specimens collected from osteosarcoma excision were studied. 30 specimens collected during the same period from benign lesion of bone （osteochondroma） operation were taken as the control group. Immunohistochemistry staining （ElivisonTM two steps method） was used to detect the expression of PTEN protein in 43 cases of osteosarcoma. SPSS 10.0 was used in statistical analysis. Results： Immunohistochemistry staining showed that the positive reaction of PTEN protein was all oriented to cytoplasm, which were brown or yellowish- brown granules. By way of X^2 test, the significant difference of the positive expressions of PTEN protein between bone benign lesion and osteosarcoma （X^2 = 7.976, P 〈 0.01） was observed. Osteosarcoma with different degrees of histodifferentiation showed different level expression of PTEN protein. There was significant difference between well-differentiated osteosarcoma （grades Ⅰ-Ⅱ） and poorly-differentiated osteosarcoma （grade Ⅲ） statistically （P 〈 0.01）. The level of expression of PTEN was negatively correlated to the histological grade of osteosarcoma. There was great significance statistically （rs=-0.4922, P 〈 0.01）. Conclusion： PTEN protein may be used as candidate gene of cancer inhibitory gene： PTEN protein is a cancer suppressor gene protein which has expression in bone tumors. It might not only be used in the study of pulmonary carcinoma and neurogliocytoma, but also in the study of bone tumor; the expression of PTEN is related to benignancy or malignancy of bone tumor and their degree of differentiation. The expression of PTEN is positively correlated with degree of differentiation.