Progenitor gene DLK1 might be an independent prognostic factor of liver cancer

Abstract

Background: Delta-like 1 homolog (DLK1) is a marker for progenitor cells of the liver. The gene encoding DLK1 is expressed early during embryonic development but, importantly, it is also expressed in some human liver cancers. However, the prognostic value of the DLK1 gene has not been investigated. Objectives: To examine the association between the DLK1 gene and survival time and whether high levels of expression of DLK1 are a prognostic factor for liver cancer. Methods: We evaluated 60 cases of primary liver cancer, and investigated the link between the expression of DLK1 and patient survival. Clinical characteristics of the cases used for our study, such as tumor size, differentiation and staging, are statistically evenly distributed. Using RT-PCR, western blotting and immunohistochemistry, we analyzed the expression of DLK1 in the tumor samples and evaluated the results statistically. Results: DLK1 was expressed in 22 of the 60 cases (36.7%), and analysis of the survival of the patients revealed that DLK1-positive patients had a shorter survival time than DLK1-negative patients. Cox regression analysis also showed that DLK1 is a risk factor. However, DLK1 expression does not seem to correlate with other classic prognostic factors such as alpha-fetoprotein (AFP), tumor-node-metastasis (TNM) and vascular invasion, which implies that it is an independent prognostic factor.

Keywords::

• DLK1
• liver cancer
• progenitor
• prognostic

Acknowledgements

The authors thank all the staff at Center Laboratory for their assistance especially Z Li, Z Tian and H Zhang. The authors also thank to G-S Feng for his help with statistical analysis.

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