Methylation status of oncogene S100A4 and antioncogene ppENK in pancreatic carcinoma

Abstract

Objective The aim of this study was to investigate the association between methylation of ppENK and S100A4 and pancreatic carcinoma. Methods 31 samples of human tissues of pancreatic cancer and adjacent tissues, five pancreatic carcinoma cell lines and one sample of normal pancreas were collected. ppENK methylation status was detected by MSP and S100A4 methylation status was detected by COBRA. The expression of S100A4 and ppENK protein was investigated by immunohistochemistry and RT-PCR. The association of methylation status of ppENK gene or S100A4 with clinical parameters of pancreatic carcinoma was analyzed. Results No methlation of ppENK was detected in normal pancreatic tissue. SI00A4 gene was highly methylated. Methylation of ppENK was detected in 90.3% of the pancreatic carcinoma tissue in 31 patients; there were no correlation between the status of ppENK methylation with clinical parameters of pancreatic carcinoma. The hypomethylation rate of S100A4 gene was 71%, and it was only related to the serum level of CA 19-9 (P=0.011, OR=0.05) ; the expression rate of S100A4 protein in pancreatic cancer tissue was 87.1%, and the expression rates were correlated with the differentiation of the tumor, namely, poorly differentiated tumor highly expressed S100A4 protein. S100A4 hyomethylation was highly correlated with ppENK methylation (P=0.019). Methylated ppENK was detected in five pancreatic cancer cell lines, and there was no ppENK mRNA expression; S100A4 gene was hypomethylated, while S100A4 mRNA was highly expressed in five pancreatic cancer cell lines. Conclusions ppENK was hypermethylated, while S100A4 was hypomethylated in pancreatic cancer tissue. Key words: Pancreatic meplasms; Methylation; ppENK; S100A4