AIM OF THE STUDY: The Ras-related tumour suppressor gene aplasia Ras homolog member I (ARHI) is downregulated in many types of cancer, including ovarian cancer and hepatocellular carcinoma. In the present study, we explore the expression level and role of ARHI in colon cancer. Moreover, the mechanisms that down-regulate expression of ARHI in colon cancer will be further investigated. MATERIAL AND METHODS: ARHI expression levels were evaluated with immunohistochemistry, reverse transcriptase-PCR, and western blot. Loss of heterozygosity (LOH), single strand conformation polymorphism (SSCP), and...