Abstract: Objective To investigate the expression of secretory leucocyte protease inhibitor (SLPI) in colon cancer and their
clinical significance. Methods Immunohistochemistry was performed to detect the SLPI expression in colon cancer tissue
microarray. The expression of SLPI was scored by two pathologists and was analyzed using χ2 test to explore its influence on
the pathologic characteristics of colon carcinoma. Results SLPI was up-regulated in colon cancer tissue compared to normal
mucosa. Overexpression of SLPI protein was correlated with differentiation grade (low differentiation: 42.1% vs 57.9% ;
moderate/well differentiation: 2.3% vs 97.7%, TNM stages(III-IV:29.4% vs 70.6%;I-II:3.1% vs 96.9%), lymph node metastasis
(28.6% vs 71.4%) and distant metastasis (84.6% vs 15.4%), but not with patient age or sex. Conclusion SLPI overexpression
correlates with aggressive pathologic characteristics of colon cancer and it may server as prognostic factor of colon cancer
patients. Further research will be carried out to verify whether SLPI can become a new target for colon cancer treatment.