Maspin expression and its clinicopathological significance in tumorigenesis and progression of gastric cancer

AIM:To investigate maspin expression in tumorigenesis and progression of gastric cancer and to explore its relevant molecular mechanisms.METHODS:Formalin-fixed and paraffin-embedded tissues from normal mucosa (n=182), dysplasia (n=69), cancer (n=l13) of the stomach were studied for maspin expression by immunohistochemistry. Microvessel density (MVD) in gastric cancer was labeled using anti-CD34 antibody. Maspin expression was compared with clinical parameters and MVD of tumors. Caspase-3 expression was also detected in gastric carcinoma by immunohistochemistry. The relationship between Caspase-3 and maspin expression was concerned as well.RESULTS:The positive rates of maspin expression were 79.8% (145/182), 75.4%(52/69) and 50.4%(57/113) in normal mucosa, dysplasia and cancer of the stomach,respectively.Cancer less frequently expressed maspin than normal mucosa and dysplasia (P<0.05).Maspin expression showed a significantly negative association with invasive depth, metastasis, Lauren's and Nakamura's classification (P<0.05),but not with tumor size, Borrmann's classification,growth pattern or TNIVl staging (P>0.05). The positive rate of Caspase-3 was significantly lower in gastric cancer than in normal gastric mucosa (P<0.05,32.7% vs 50.4%). It was noteworthy that maspin expression was negatively correlated with MVD, but positively correlated with expression of Caspase-3 in gastric cancer (P<0.05).CONCLUSION:Down-regulated maspin expression is a late molecular event in gastric carcinogenesis. Reduced expression of maspin contributes to progression of gastric cancer probably by inhibiting cell adhesion, enhandng cell mobility,decreasing cell apoptosis and facilitating angiogenesis.Additionally altered expression of maspin underlies the molecular mechanism of differentiation of gastric cancer and supports the different histogenetic pathways of intestinal and diffuse gastric cancers. Maspin expression can be considered as an effective and objective marker to reveal biological behaviors of gastric cancer.

Growth,invasion,metastasis,differentiation,angiogenesis and apoptosis of gastric cancer regulated by expression of PTEN encoding products

AIM: To investigate expression of PTEN in gastric cancer and to explore its roles in tumorigenesis and progression of gastric cancer.METHODS: Formalin-fixed and paraffin-embedded tissues of adjacent non-tumor mucosa and primary foci from 113cases of gastric cancers were studied for the expression of PTEN and Caspase-3 andmicrovessel density (MVD)by streptavidin-peroxidase (S-P) immunohistochemistry with antibodies against PTEN, Caspase-3, and CD34. The relationship between PTEN and Caspase 3 expression and clinicopathological parameters of tumors was compared.RESULTS: Primary gastric cancer cells expressed PTEN less frequently than adjacent epithelial cells of primary foci (54.9％ vs89.4％; P=0.000, χ2=33.474). PTEN expression was significantly associated with invasive depth (P=0.003,rs=0.274), metastasis (P=0.036, rs=0.197), growth pattern (P=0.008, rs=0.282), Lauren′s classification (P=0.000,rs=0.345), and histological classification (P=0.005, rs=0.262)of tumors, but not with tumor size (P=0.639, rs=0.045),Borrmann′s classification (P=0.544, rs=0.070) or TNM staging (P=0.172, rs=0.129). PTEN expression was negatively correlated with MDV in primary gastric cancer (P=0.020,F=5.558). Primary gastric cancer cells showed less frequent immunoreactivity to Caspase-3 than adjacent epithelial cells of primary foci (32.7 ％ vs 50.4 ％; P=0.007,χ2=7.286).Caspase-3 expression was dependent of PTEN expression in primary gastric cancer cells (P=0.000, χ2=15.266).CONCLUSION: Down-regulated expression of PTEN plays an important role in tumorigenesis, progression, growth,differentiation and angiogenesis of gastric cancer. Low expression of PTEN can decrease expression of Caspase-3to disorder apoptosis of tumor cells, which might explain the molecular mechanisms of PTEN contributions to tumorigenesis and progression of gastric cancer.

EXPRESSION OF MASPIN AND KAI1 AND THEIR CLINICOPATHOLOGICAL SIGNIFICANCE IN CARCINOGENESIS AND PROGRESSION OF GASTRIC CANCER

To investigate the roles of maspin and kai1 expression in tumorigenesis and progression of gastric cancer. Methods Maspin and kai1 expressions were detected in normal gastric mucosa (n = 182), gastric dysplasia (n = 69), and gastric cancer (n = 113) by immunohisto-chemistry. Their expressions were compared with clinicopathological parameters of tumors. Relationship between maspin and kai1 expression was also concerned in gastric cancer. Results The positive rates of maspin expression were 79.8% (145/182), 75.4% (52/69), and 50.4% (57/113) in normal gastric mucosa, gastric dysplasia, and gastric cancer, while those of kai1 expression were 81.9% (149/182), 65.2% (49/69), and 58.4% (66/113) in corresponding tissues respectively. Gastric cancer less frequently expressed maspin than the normal gastric mucosa and gastric dysplasia (P < 0.05), while dysplasia and cancer showed less frequent expression of kai1 than normal mucosa (P < 0.05). Maspin expression showed negative association with invasive depth, metastasis, Lauren’s and histological classifications (P < 0.05), but not with tumor size, Borrmann’s classification, growth pattern or TNM staging (P > 0.05). Kai1 expression was negatively correlated with invasive depth, metastasis, growth pattern, Lauren’s and histo-logical classifications (P < 0.05), but not with tumor size, Borrmann’s classification or TNM staging (P > 0.05). Maspin and kai1 were collaboratively expressed in gastric cancer (P < 0.05). Conclusions Down-regulated expressions of maspin and kai1 play an important role in gastric carcinogenesis. Abnormal expression of maspin and kai1 might have inhibitory effects on invasion and metastasis of gastric cancer and act as an effe-ctive and objective marker to indicate the pathobiological behaviors of gastric cancer.

EST-based Analysis of Gene Expression in the Porcine Brain

Since pig is an important livestock species worldwide, its gene expressionhas been investigated intensively, but rarely in brain. In order to study gene expression profilesin the pig central nervous system, we sequenced and analyzed 43,122 high-quality 5'' end expressedsequence tags (ESTs) from porcine cerebellum, cortex cerebrum, and brain stem cDNA libraries,involving several different prenatal and postnatal developmental stages. The initial ESTs wereassembled into 16,101 clusters and compared to protein and nucleic acid databases in GenBank. Ofthese sequences, 30.6% clusters matched protein databases and represented function known sequences;75.1% had significant hits to nucleic acid databases and partial represented known function; 73.3%matched known porcine ESTs; and 21.5% had no matches to any known sequences in GenBank. We used thecategories defined by the Gene Ontology to survey gene expression in the porcine brain.