Screening of Glypican-6 Expression in Benign, Primary and Metastatic Colon Cancers

Background: The development of colon cancer has been described as a multistep process of carcinogenesis. Understanding molecular and cellular changes underlying this process is required to determine potential biomarkers and therapeutic targets in colon cancers. Several molecular entities, including glypicans, are implicated in cancer development. Among these is glypican-6, which is overexpressed in a limited number of cancers. This study aims to characterise the glypican-6 expression in different types of colon cancer. Methods: Immunohistochemistry was used to characterise glypican-6 expression in a panel of archived formalin-fixed, paraffin-embedded colon tissue types. These types included 39 normal colon tissues, 10 colon tubular adenomas, 60 colon adenocarcinomas without metastasis and 60 colon adenocarcinomas with metastasis. Glypican-6 expression relation to demographic and clinicopathologic features was also examined. Results: Glypican-6 was strongly expressed in benign, primary and metastatic colon tumours. Normal tissue samples exhibited low to undetectable levels of glypican-6. A significantly high glypican-6 expression was displayed in colon cancers with lymph node metastasis, high depth of invasion, distant metastasis, high histological grades and late stages of the disease (P < 0.05). Importantly, a significant differential in glypican-6 expression was found between normal tissues and different types of colon cancer tissues. Moreover, the highest glypican-6 expression was more frequently found in metastatic tumours, followed by primary tumours and the least in benign tumours (P < 0.05). Conclusions: Selective expression of glypican-6 may establish a basis for potential use as a tissue biomarker or as a novel therapeutic target in treatment of colon cancer.