Overexpression of PAK-1 is an independent predictor of disease recurrence in colorectal carcinoma

Background: Colorectal carcinoma (CRC) is a significant cause of major morbidity and mortality. PAK-1 is a protein that regulates cytoskeletal dynamics and cell motility. The purpose of the present study is to investigate the relationship between PAK-1 immunoexpression and CRC progression and its validity as an independent prognostic factor. Patients and methods: Paraffin blocks of 103 primary CRCs and 37 nodal metastases were retrieved and tissue microarrays were constructed. Immunohistochemistry was performed using anti-PAK-1 antibody. Immunostaining was scored and results were analysed in relation to clinicopathological parameters. Results: PAK-1 was overexpressed in primary CRC (P<0.001). No difference between low and high expression in nodal metastasis (P=0.139). There was no difference between PAK-1 immunoexpression in primary and nodal metastasis (P=0.275). High PAK-1 immunoexpression was associated with disease recurrence (P=0.03). However, there was no association with most clinicopathological parameters. PAK-1 overexpression was detected as an independent predictor of disease recurrence (P=0.05). No association was found between PAK-1 immunoexpression and disease free survival (log-rank =1.287, P=0.257). Conclusion: PAK-1 overexpression may be involved in CRC progression and could be considered an independent predictor of disease recurrence. Further in vivo and in vitro molecular studies are needed to investigate the role of PAK-1 in colorectal carcinogenesis.