Epigenetic screening of salivary gland mucoepidermoid carcinoma identifies hypomethylation of CLIC3 as a common alteration

Zhiming Wang, Shizhang Ling, Eleni Rettig, Ryan Sobel, Marietta Tan, Elana J. Fertig, Michael Considine, Adel K. El-Naggar, Mariana Brait, Carole Fakhry, Patrick K. Ha

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Objectives The role of promoter methylation in the development of mucoepidermoid carcinoma (MEC) has not been fully explored. In this study, we investigated the epigenetic landscape of MEC. Methods The Illumina HumanMethylation27 BeadChip array and differential methylation analysis were utilized to screen for epigenetic alterations in 14 primary MEC tumors and 14 matched normal samples. Bisulfite sequencing was used to validate these results, with subsequent quantitative Methylation-Specific PCR (qMSP) to validate chloride intracellular channel protein 3 (CLIC3) in a separate cohort. Furthermore, CLIC3 immunohistochemical (IHC) staining was performed in another separate cohort of MEC. Finally, clinical and pathological characteristics were statistically analyzed for correlation with methylation status of CLIC3 and CLIC3 IHC H-scores by Wilcoxon rank sum, Kruskall-Wallis, and X2 test tests. Results We obtained 6 significantly differentially methylated gene candidates demonstrating significant promoter hyper- or hypo-methylation from the array data. Using bisulfite sequencing, we found one gene, CLIC3, which showed differential methylation between MEC tumor and normal samples in a small validation cohort. qMSP analysis of the CLIC3 promoter in a separate validation set showed significantly lower methylation level in tumor than in normal. The level of CLIC3 methylation in MECs was not statistically correlated with clinical or pathological characteristics. However, IHC staining intensity and distribution of CLIC3 were significantly increased in MECs, compared with those of normal salivary gland tissues. Conclusions Hypomethylation of CLIC3 promoter and its overexpression are significant events in MEC. Its functional role and potential therapeutic utility in MEC are worthy of further exploration.

Original languageEnglish (US)
Pages (from-to)1120-1125
Number of pages6
JournalOral Oncology
Volume51
Issue number12
DOIs
StatePublished - Dec 2015

Keywords

  • Array
  • Bisulfite sequencing
  • CLIC3
  • DNA methylation
  • H-score
  • Head and neck cancer
  • Immunohistochemistry
  • Methylation-specific PCR
  • Mucoepidermoid carcinoma

ASJC Scopus subject areas

  • Oral Surgery
  • Oncology
  • Cancer Research

Fingerprint

Dive into the research topics of 'Epigenetic screening of salivary gland mucoepidermoid carcinoma identifies hypomethylation of CLIC3 as a common alteration'. Together they form a unique fingerprint.

Cite this