Genome-wide screening of DNA methylation associated with lymph node metastasis in esophageal squamous cell carcinoma.

Hiroaki Nagata,Naoto Fujiwara,Hidekazu Hiramoto,Tomoki Muramatsu,Satoru Miyano,Daisuke Ichikawa,Tatsuyuki Kawano,Kousuke Tanimoto,Johji Inazawa,Eigo Otsuji,Ken-Ichi Kozaki,Seiya Imoto

doi:10.18632/oncotarget.17147

Abstract

Lymph node metastasis (LNM) of esophageal squamous cell carcinoma (ESCC) is well-known to be an early event associated with poor prognosis in patients with ESCC. Recently, tumor-specific aberrant DNA methylation of CpG islands around the promoter regions of tumor-related genes has been investigated as a possible biomarker for use in early diagnosis and prediction of prognosis. However, there are few DNA methylation markers able to predict the presence of LNM in ESCC. To identify DNA methylation markers associated with LNM of ESCC, we performed a genome-wide screening of DNA methylation status in a discovery cohort of 67 primary ESCC tissues and their paired normal esophageal tissues using the Illumina Infinium HumanMethylation450 BeadChip. In this screening, we focused on differentially methylated regions (DMRs) that were associated with LNM of ESCC, as prime candidates for DNA methylation markers. We extracted three genes, HOXB2, SLC15A3, and SEPT9, as candidates predicting LNM of ESCC, using pyrosequencing and several statistical analyses in the discovery cohort. We confirmed that HOXB2 and SEPT9 were highly methylated in LNM-positive tumors in 59 ESCC validation samples. These results suggested that HOXB2 and SEPT9 may be useful epigenetic biomarkers for the prediction of the presence of LNM in ESCC.

Highlights

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal cancers in spite of recent advancements in its diagnosis and therapeutics [1, 2]
We focused on differentially methylated regions (DMRs) that were associated with Lymph node metastasis (LNM) of esophageal squamous cell carcinoma (ESCC), as prime candidates for DNA methylation markers
We confirmed that Homeobox B2 (HOXB2) and Septin 9 (SEPT9) were highly methylated in LNM-positive tumors in 59 ESCC validation samples

Summary

Introduction

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal cancers in spite of recent advancements in its diagnosis and therapeutics [1, 2]. One of the reasons for its poor prognosis is due to the development of lymph node metastasis (LNM) in the early phases [3]. Early diagnosis and treatment are essential for ESCC patients. Predicting the presence of LNM before treatment is important for deciding appropriate therapy. Indication of ESD requires early stage ESCC, in which the rate of LNM is low. If ESD is not indicated, esophagectomy with lymph node dissection is chosen as the alternative for radical treatment. Most patients are diagnosed at latestage, and are often accompanied with extensive lymph node metastases. The degree of lymph node metastasis has been regarded as the most important prognostic factor in late stage disease [4, 5]

Methods

Results

Conclusion