The role of sialyl transferases as indicator of metastatic phenotype and clinicopathologic properties in colorectal cancer

Objective: In our study we aimed to evaluate the role of sialyl transferases which are important molecules to maintain of sialic acid metabolism, in the determination of metastatic phenotype and determination of the function of selecting the metastasis target organ. Method: In this study,the expression of sialyl transferases was analyzed with multiplex PCR array methods in paraffine embedded pathological tissue samples of 26 colorectal cancer patients with peritoneal carcinomatosis or liver metastases who had undergone surgery in Dokuz Eylul University Hospital between 2004 and 2014 years. Results: In comparative analysis the expression levels of ST3GAL1, ST3GAL2, ST6GAL1 and ST6GAL2 enzymes were upregulated at peritoneal carcinomatosis while those were downregulated at liver metastases. Compared with normal mucosa the expression levels of ST6GAL1, ST3GAL1 and ST3GAL2 leves were upregulated in primary tumor (fold change 1.65; p=0.038 Mann Whitney U Test), and ST3GAL2 level was upregulated in peritoneal carcinomatosis (fold change1.87; p=0.028). While peritoneal carcinomatosis and liver metastases were compared, the expression levels of ST6GAL1 (fold change 4.52; p=0.029) and ST3GAL1 ( fold change 12,53; p=0.029) were upregulated in peritoneal carcinomatosis statistically significant, but the increase of ST3GAL2 (p=0.057) upregulation was statistically nonsignificant. Conclusion: ST3GAL1, ST3GAL2, ST6GAL1 and ST6GAL2 expression levels increase in peritoneal metastases in colorectal cancers. Expression levels of ST3GAL1, ST3GAL2 and ST6GAL1 are reduced in liver metastasis of colorectal cancers Key words: Colorectal Cancer, Peritoneal Carcinomatosis, liver metastasis, sialic acid, sialyl transferase, glycobiology.