Ataxin-3 expression correlates with the clinicopathologic stage and prognosis of colorectal cancer

Introduction: We designed this study to investigate the expression of Ataxin-3 in human colorectal cancer (CRC) tissues, and explore its clinical pathologic significance. Methods: The expression of Ataxin-3 in CRC (n = 168) was determined by immunohistochemistry and correlated to clinicopathologic features such as TNM stage and presence of recurrence. The expression of Ataxin-3 protein in the CRC lines HT-29 was evaluated by Western blot analysis. Results: Examination of CRC sections for the immunoreactivity of Ataxin-3 showed weak Ataxin-3 staining (0 or + 1) in 132 of the 168 cases, and these were classified as the weak-positive group. The remaining 36 cases exhibited strong Ataxin-3 staining (+2 or + 3) and were classified as the strong-positive group. The immunoreactivity of Ataxin-3 in CRC specimens was markedly lower than that in noncancerous tissues. The expression levels of Ataxin-3 were compared with the clinical and pathologic characteristics of 168 patients with CRC. The levels of Ataxin-3 expression were negatively correlated with TNM stages (P < 0.05) and were significantly lower in patients with lymph node metastasis (P < 0.05) and with tumor recurrence (P < 0.05). Conclusion: Decreased expression of Ataxin-3 may play an important role in colorectal carcinogenesis.