Background: ARID1A has been described as a tumor suppressor gene, participating in the chromatin re-modeling. We aimed to investigate the incidence of ARID1A expression loss and analyze the relationship between ARID1A status and both survival rates and clinicopathologic characteristics such as Microsatellite instability (MSI) in patients with colorectal cancer (CRC).

immunohistochemical analysis of the expression of ARID1A protein and MSI testing was performed on 27 and 18 paired CRC and adjacent normal tissues, respectively.

Among the 27 CRC tumors studied, 9 tumors (33.3 %) and 8 tumors (29.6%) showed negative or low ARID1A expression, respectively. No significant difference in ARID1A expression was observed concerning both overall survival and any of the examined clinicopathological parameters

ARID1A expression is frequently downregulated in CRC tissues. This finding confirms the involvement of loss of expression of the ARID1A in CRC development. There was no significant association between the ARID1A expression loss and any clinicopathological characteristics examined. Future in vivo analysis required to establish this role.