Expression and significance of the Wip1 proto-oncogene in colorectal cancer.

Aim: To investigate the level of expression of proto-oncogene Wip1 and its physiological significance in colorectal cancer. Methods: Immunohistochemistry, semi-quantitative RT-PCR, and Western blotting were used to analyze Wip1 mRNA and protein expression in 120 cases of colorectal cancer and normal tissues to study relationships with clinical symptoms and disease prognosis. Results: The level of Wip1 protein expression was found to be significantly higher in colorectal cancer tissues (85% (102/120)) than in normal tissues (30% (36/120)) (P < 0.05). The relative amount of Wip1 protein in colorectal cancer tissue was also found to be significantly higher (P < 0.05) than in normal tissues (1.060 +/- 0.02 and 0.640 +/- 0.023, respectively). Semi-quantitative RT-PCR showed average Wip1 mRNA expression levels to be 1.113 +/- 0.018 and 0.658 +/- 0.036 for colorectal cancer tissue and adjacent normal tissue (P < 0.05). The level of Wip1 protein expression was not correlated with age, gender, or tumor site, but appeared linked with lymph node metastasis, Dukes stage, histological grade, and liver metastasis. Individuals with high and low levels of Wip1 expression showed statistically significant differences in the five-year overall survival and recurrence-free survival rates (P < 0.05). Conclusion: Wip1 mRNA and protein are highly expressed in colorectal cancers and may be associated with colorectal cancer development and progression.