Alteration of somatostatin receptor subtype 2 gene expression in pancreatic tumor angiogenesis.
OBJECTIVE
To explore the difference of somatostatin receptor subtype 2 (SST2R) gene expression in pancreatic cancerous tissue and its adjacent tissue, and the relationship between the change of SST2R gene expression and pancreatic tumor angiogenesis related genes.


METHODS
The expressions of SST2R, DPC4, p53 and ras genes in cancer tissues of 40 patients with primary pancreatic cancer, and the expression of SST2R gene in its adjacent tissue were determined by immunohistochemiscal LSAB method and EnVision(TM) method. Chi-square test was used to analyze the difference in expression of SST2R in pancreatic cancer tissue and its adjacent tissue, and the correlation of SST2R gene expression with the expression of p53, ras and DPC4 genes.


RESULTS
Of the tissue specimens from 40 patients with primary pancreatic cancer, 35 (87.5%) cancer tissues showed a negative expression of SST2R gene, whereas 34 (85%) a positive expression of SST2R gene in its adjacent tissues. Five (12.5%) cancer tissues and its adjacent tissues simultaneously expressed SST2R. The expression of SST2R gene was markedly higher in pancreatic tissues adjacent to cancer than in pancreatic cancer tissues (P<0.05). The expression rates of p53, ras and DPC4 genes were 50%, 60% and 72.5%, respectively. There was a significant negative correlation of SST2R with p53 and ras genes (chi(1)(2)=9.33, chi(2)(2)=15.43, P<0.01), but no significant correlation with DPC4 gene (chi(2)=2.08, P>0.05).


CONCLUSIONS
There was a significant difference of SST2R gene expression in pancreatic cancer tissues and its adjacent tissues, which might be one cause for the different therapeutic effects of somatostatin and its analogs on pancreatic cancer patients. There were abnormal expressions of SST2R, DPC4, p53 and ras genes in pancreatic carcinogenesis, and moreover, the loss or decrease of SST2R gene expression was significantly negatively correlated with the overexpression of tumor angiogenesis correlated p53 and ras genes, suggesting that SST2R gene together with p53 and ras genes may participate in pancreatic cancerous angiogenesis.
Qin
Ren-Yi
RY
Department of Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, Province, China. ryqin@tjh.tjmu.edu.cn
Fang
Ru-Liang
RL
Gupta
Manoj Kumar
MK
Liu
Zheng-Ren
ZR
Wang
Da-Yu
DY
Chang
Qing
Q
Chen
Yi-Bei
YB
D000230:Adenocarcinoma / Q000473:pathology / Q000503:physiopathology*; D000328:Adult; D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology / Q000503:physiopathology*; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000473:pathology / Q000503:physiopathology*; D010190:Pancreatic Neoplasms / Q000473:pathology / Q000503:physiopathology*; D017481:Receptors, Somatostatin / Q000235:genetics*; D051901:Smad4 Protein; D015534:Trans-Activators / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D018631:ras Proteins / Q000235:genetics
D004268:DNA-Binding Proteins; D017481:Receptors, Somatostatin; C497796:SMAD4 protein, human; D051901:Smad4 Protein; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; C093733:somatostatin receptor 2; D018631:ras Proteins