Matrix metalloproteinase-2 and tissue inhibitor of metallo-proteinase-2 in colorectal carcinoma invasion and metastasis

AIM: To explore the relationship between matrix metallopr- oteinase-2 (MMP-2) and tissue inhibitor of metallopr- oteinase-2 (TIMP-2) in the development of colorectal carcinoma and to provide a valuable marker for clinical diagnosis. METHODS: Twenty-five patients with colorectal carcinoma underwent surgical resection. Samples were taken from tumor sites and normal tissues. MMP-2 activity was determined by gelatin zymography. Western blot and ABC immunohist-ochemical staining were used to detect the expression levels of MMP-2 and TIMP-2 in normal and colorectal carcinoma tissues. Statistical analyses were performed using the Student's t test and one-way ANOVA. P<0.05 was considered statistically .significant. All the statistical analyses were performed using SPSS 10.0 software. RESULTS: MMP-2 activity could be detected in both normal and colorectal carcinoma tissues. MMP-2 activity in colorectal carcinoma tissues was much higher than that in normal tissues (P<0.05, t=3.916,4.227). MMP-2 activity was positively related to the colorectal carcinoma invasion depth, lymph node metastasis and Duke's stage. Western blot and ABC immunohistochemical staining demonstrated that the expression level of MMP-2 in colorectal carcinoma tissues was much higher than that in normal tissues (P<0.05, t = 9.429), but the expression level of TIMP-2 in colorectal carcinoma tissues was much lower than that in normal tissues (P<0.05, t = 7.329). The MMP-2/TIMP-2 ratio of colorectal carcinoma was much higher than that of normal tissues. With the progression of invasion depth, lymph node metastasis and tumor Duke's stage, the activity and expression level of MMP-2 and TIMP-2 gradually increased, but the MMP-2/TIMP-2 ratio gradually decreased. CONCLUSION: The balance between MMP-2 and TIMP-2 plays a crucial role in the process of colorectal carcinoma invasion and metastasis.

Expression of Bcl-2 and Bax in extrahepatic biliary tract carcinoma and dysplasia

AIM: To compare the difference of expression of Bcl-2 and Bax in extrahepatic biliary tract carcinoma and dysplasia, and to analyze the role of Bcl-2 and Bax proteins in the progression from dysplasia to carcinoma and to evaluate the correlation of Bcl-2/Bax protein expression with the biological behaviors.METHODS: Expressions of Bcl-2 and Bax were examined immunohistochemically in 27 cases of extrahepatic biliary tract carcinomas (bile duct carcinoma: n=21, carcinoma of ampulla of Vater: n=6), and 10 cases of atypical dysplasia.Five cases of normal biliary epithelial tissues were used as controls. A semiquantitative scoring system was used to assess the Bcl-2 and Bax reactivity.RESULTS: The expression of Bd-2 was observed in 10 out of 27 (37.0 %) invasive carcinomas, 1 out of 10 clysplasias, none out of 5 normal epithelial tissues. Bax expression rate was 74.1% (20/27) in invasive carcinoma, 30 % (3/10) in dysplasia,and 40 % (2/5) in normal biliary epithelium. Bcl-2 and Bax activities were more intense in carcinoma than in dysplasia,with no significant difference in Bcl-2 expression (P=0.1:10),and significant difference in Bax expression (P=0.038). Level of Bax expression was higher in invasive carcinoma than in dysplasia and normal tissue (P=0.012). Bcl-2 expression was correlated to Bax expression (P=0.0059). However, Bcl-2/Bax expression had no correlation with histological subtype,grade of differentiation, or level of invasion.CONCLUSION: Increased Bcl-2/Bax expression from dysplasia to invasive tumors supports the view that this is the usual route for the development of extrahepatic biliary tract carcinoma. Bcl-2/Bax may be involved, at least in part,in the apoptotic activity in extrahepatic biliary carcinoma.

Research and control of well water pollution in high esophageal cancer areas

AIM: In order to detect risk factors for esophageal cancer,a national research program was carried out during the Eighth Five-Year Plan (from 1991 to 1995). METHODS: Cixian County and Chichen County in Hebei Province were selected as the index and the control for the study fields with higher or lower incidence of esophagus cancer in China, respectively. In these areas, we investigated the pollution of three nitrogenous compounds in well water for drinking and the use of nitrogen fertilizer in farming. RESULTS: In well water, nitrate nitrogen, nitrite nitrogen and ammonia nitrogen were 8.77 mg/L, 0.014 mg/L and 0.009 mg/L in Cixian County in 1993, respectively. They were significantly higher than their levels (3.84 mg/L, 0.004 mg/L and 0.004 mg/L) in Chichen County (P＜0.01, t=6.281,t=3.784,t=3.775). There was a trend that the nitrogenous compounds in well water increased from 1993 to 1996.The amount of nitrogen fertilizer used in farming was 787.6 kg per hectare land in Cixian County in 1991, significantly higher than 186 kg per hectare in Chichen County (t=9.603,P＜0.001). CONCLUSION: These investigations indicate that the poilution of nitrogenous compounds in well water for drinking is closely related to the use of nitrogen fertlizer in farming, and there is a significantly positive correlation between the level of three nitrogenous compounds in well water and the mortality ofesophageal cancer (correlation coefficient =0.5992). We suggest that improvement of well system for drinking water quality should be an effective measure for esophageal cancer prevention and control in rural areas.

Clinicopathologic Observations on Small Cell Carcinoma of the Esophagus

OBJECTIVE To investigate the histogenesis and biological characteristics and factors influencing prognosis of small cell carcinoma of the esophagus(ESCC).METHODS The expression of CK, NSE, Syn, CHr-A and CD56 proteins were detected immunohistochemically in 63 cases of small cell carcinoma of the esophagus.RESULTS The ESCC cases were divided into two groups as follows: a puresmall cell group (28/63) and compound small cell group (35/63). Theimmunohistochemistry results were positive for: CK in 41.3%, NSE in 36.5%,Syn in 90.5%, CHr-A in 60.3% and CD56 in 50.8%. The difference betweenstaining of the pure small cell carcinoma and compound small cellcarcinoma was not statistically significant. The size and depth of tumorinvasion, the positive residual incision edge and lymph node metastasiswere the major factors influencing long-term survival.CONCLUSION Small cell carcinoma of the esophagus is a highly malignanttumor, which expresses neuroendocrine antigens. The histophathologicorigin is still unknown but the non-neuroepithelial origin was accepted in thisstudy.