Expression and clinical significance of DLK1 and MMP-9 in cholangiocarcinoma

Objective To investigate the expression of delta drosophila homolog- like 1 ( DLK1) and matrix metalloproteinase 9 ( MMP- 9) in cholangiocarcinoma tissue and to analyse their clinical significance and the correlation between DLK1 and MMP- 9. Methods Cholangiocarcinoma tissues were collected from 96 patients who were pathologically diagnosed with cholangiocarcinoma from 2001 to 2010, and normal bile duct tissues were collected from 20 normal persons. The expression of DLK1 and MMP- 9 in cholangiocarcinoma tissues or normal bile duct tissues was measured by immunohistochemical S- P method. Chi- square test was performed using SPSS 17. 0. Correlation analysis was performed by Spearman's correlation test. Results The positive expression rates of DLK1 and MMP- 9 in cholangiocarcinoma tissues were 59. 38% and 79. 17%, respectively, significantly higher than those in normal bile duct tissues ( 0 and 15%) ( χ2= 23. 35, P < 0. 05; χ2= 31. 37, P < 0. 05) . The expression of DLK1 was correlated with the differentiation degree in cholangiocarcinoma ( χ2= 7. 46, P < 0. 05) ; the expression of MMP- 9 was correlated with the differentiation degree and lymph node metastasis in cholangiocarcinoma ( χ2= 7. 28, P < 0. 05; χ2= 9. 67, P < 0. 05) , but was not correlated with sex, age, and tumor size ( P > 0. 05) . There was a positive correlation between the expression of DLK1 and MMP- 9 ( r = 0. 41, P < 0. 05) . Conclusion DLK1 and MMP- 9 are highly expressed in cholangiocarcinoma, and they are positively correlated, suggesting that they are associated with the development, progression, invasion, and metastasis of cholangiocarcinoma. The detection of the two indicators provides a reference for the diagnosis and treatment of cholangiocarcinoma.