Alteration of somatostatin receptor subtype 2 gene expression in pancreatic tumor angiogenesis

AIM:To explore the difference of somatostatin receptorsubtype 2 (SST2R) gene expression in pancreatic canceroustissue and its adjacent tissue,and the relationship betweenthe change of SST2R gene expression and pancreatic tumorangiogenesis related genes.METHODS:The expressions of SST2R,DPC4,p53 and rasgenes in cancer tissues of 40 patients with primary pancreaticcancer,and the expression of SST2R gene in its adjacenttissue were determined by immunohistochemiscal LSABmethod and EnVisionTMmethod.Chi-square test was usedto analyze the difference in expression of SST2R in pancreaticcancer tissue and its adjacent tissue,and the correlation ofSST2R gene expression with the expression of p53,ras andDPC4 genes.RESULTS:Of the tissue specimens from 40 patients withprimary pancreatic cancer,35 (87.5%) cancer tissues showeda negative expression of SST2R gene,whereas 34 (85%) apositive expression of SST2R gene in its adjacent tissues.Five (12.5%) cancer tissues and its adjacent tissuessimultaneously expressed SST2R.The expression of SST2Rgene was markedly higher in pancreatic tissues adjacent tocancer than in pancreatic cancer tissues (P<0.05).Theexpression rates of p53,ras and DPC4 genes were 50%,60% and 72.5%,respectively.There was a significant negativecorrelation of SST2R with p53 and ras genes (X~2=9.33,x~2=15.43,P<0.01),but no significant correlation with DPC4gene (X~2=2.08,P>0.05).CONCLUSION:There was a significant difference of SST2Rgene expression in pancreatic cancer tissues and its adjacenttissues,which might be one cause for the differenttherapeutic effects of somatostatin and its analogs onpancreatic cancer patients.There were abnormal expressionsof SST2R,DPC4,p53 and ras genes in pancreaticcarcinogenesis,and moreover,the loss or decrease of SST2Rgene expression was significantly negatively correlated withthe overexpression of tumor angiogenesis correlated p53and ras genes,suggesting that SST2R gene together withp53 and ras genes may participate in pancreatic cancerousangiogenesis.