220P - Cytokeratin 19, a novel prognostic biomarker for hepatocellular carcinoma, is regulated by DNA methylation

Date 28 September 2014
Event ESMO 2014
Session Poster Display session
Topics Hepatobiliary Cancers
Translational Research
Presenter Naosuke Yokomichi
Citation Annals of Oncology (2014) 25 (suppl_4): iv58-iv84. 10.1093/annonc/mdu326
Authors N. Yokomichi1, T. Nagasaka2, N. Nishida3, F. Taniguchi4, K. Yoshida1, F. Tomokazu1, T. Kawai1, Y. Takehara1, K. Kimura1, Y. Mori1, R. Inada1, Y. Umeda5, T. Yagi5, A. Goel6, T. Fujiwara5
  • 1Gastroenterological Surgery, Okayama University Graduate School of Medicine, Density, Pharmaseutical Sciences, 700-8558 - Okayama/JP
  • 2Gastroenterological Surgery, Okayama University, 700-8558 - Okayama/JP
  • 3Department Of Gastroenterology And Hepatology, Kinki University Faculty of, Osaka/JP
  • 4Gastroenterological Surgery, Okayama University Graduate School of Medicine,Denistry and Pharmaseutical Sciences, 700-8558 - Okayama/JP
  • 5Department Of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama/JP
  • 6Department Of Internal Medicine And Charles A, Baylor University Medical, Dallas/US

Abstract

Aim

The expression of CK19 protein has recently been proposed as a novel predictor for poor prognosis following curative resection in patients with hepatocellular carcinoma (HCC). While the mechanisms underlying regulation of CK19 expression in HCC remain unclear, the presence of a CpG island within its promoter region implicates DNA methylation as a potential epigenetic process in this malignancy.

Methods

A panel of 564 surgically resected HCCs at Okayama University between 2000 and 2010 were analyzed for CK19 expression and its promoter methylation status. Among all HCCs, we excluded all tumors with recurrence, cancers with TNM stage ≥IIIB, lesions with preoperative therapy, transplantation, and combined hepatocellular-cholangiocarcinomas. CK19 expression was evaluated by immunohistochemistry in FFPE tissues. CK19 promoter methylation was evaluated for region 1 and region 2 by Hi-SA - a modified COBRA by which fluorescence labeled DNA fragments are detected using a genetic analyzer (Nagasaka T et al., JNCI 2009). Molecular results were correlated with clinicopathological features, followed by Kaplan-Meier survival analysis.

Results

A total of 125 cases matched for the selection criteria. Among these, 29 HCCs demonstrated positive CK19 staining, and these patients corresponded with significantly poor survival following surgery (p = 0.025), and extra-hepatic metastasis-free survival (p = 0.017). Multivariate analysis revealed that CK19-positive was an independent prognostic factor for survival, following surgery (HR2.85, 95%CI 1.21-6.41, p = 0.018). Methylation analysis revealed that methylation rates at both regions of CK19 gene were statistically higher in HCCs with loss of CK19 expression compared to CK19-positive group (p = 0.0002, p < 0.0001, respectively). Based on the cut off value according to the ROC curve, all methylated cases in region 1 (n = 20) and region 2 (n = 22) demonstrated negative CK19 staining (p = 0.0067, p = 0.0017, respectively).

Conclusions

Our data report that CK19 expression is an important prognostic biomarker for HCC. Furthermore, since CK19's expression was strongly associated with the methylation of its promoter region, our study provides novel mechanistic insights for the participation of this epigenetic alteration in the development of HCC.

Disclosure

All authors have declared no conflicts of interest.