DNA methylation profiling in MEN1-related pancreatic neuroendocrine tumors reveals a potential epigenetic target for treatment

E B Conemans, L Lodewijk, C B Moelans, G J A Offerhaus, C R C Pieterman, F H Morsink, O M Dekkers, W W de Herder, A R Hermus, A N van der Horst-Schrivers, M L Drent, P H Bisschop, B Havekes, L A A Brosens, K M A Dreijerink, I H M Borel Rinkes, H Th M Timmers, G D Valk, M R Vriens

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

OBJECTIVE: Epigenetic changes contribute to pancreatic neuroendocrine tumor (PanNET) development. Hypermethylation of promoter DNA as a cause of tumor suppressor gene silencing is a well-established oncogenic mechanism that is potentially reversible and therefore an interesting therapeutic target. Multiple endocrine neoplasia type 1 (MEN1) is the most frequent cause of inherited PanNETs. The aim of this study was to determine promoter methylation profiles in MEN1-related PanNETs.

DESIGN AND METHODS: Methylation-specific multiplex ligation-dependent probe amplification was used to assess promoter methylation of 56 tumor suppressor genes in MEN1-related (n = 61) and sporadic (n = 34) PanNETs. Differences in cumulative methylation index (CMI), individual methylation percentages and frequency of promoter hypermethylation between subgroups were analyzed.

RESULTS: We found promoter methylation of a large number of potential tumor suppressor genes. CMI (median CMI: 912 vs 876, P = 0.207) was the same in MEN1-related and sporadic PanNETs. We found higher methylation percentages of CASP8 in MEN1-related PanNETs (median: 59% vs 16.5%, P = 0.002). In MEN1-related non-functioning PanNETs, the CMI was higher in larger PanNETs (>2 cm) (median: 969.5 vs 838.5; P = 0.021) and in PanNETs with liver metastases (median: 1036 vs 869; P = 0.013). Hypermethylation of MGMT2 was more frequent in non-functioning PanNETs compared to insulinomas (median: 44.7% vs 8.3%; P = 0.022). Hypermethylation of the Von Hippel-Lindau gene promoter was observed in one MEN1-related PanNET and was associated with loss of protein expression.

CONCLUSION: Promoter hypermethylation is a frequent event in MEN1-related and sporadic PanNETs. Targeting DNA methylation could be of therapeutic value in MEN1 patients with advanced PanNETs.

Original languageEnglish
Pages (from-to)153-160
Number of pages8
JournalEuropean journal of endocrinology
Volume179
Issue number3
Early online date1 Sept 2018
DOIs
Publication statusPublished - 1 Sept 2018

Keywords

  • Adult
  • Aged
  • Aged, 80 and over
  • DNA Methylation/genetics
  • Epigenesis, Genetic/genetics
  • Female
  • Genes, Tumor Suppressor
  • Humans
  • Male
  • Middle Aged
  • Multiple Endocrine Neoplasia Type 1/genetics
  • Neuroendocrine Tumors/genetics
  • Pancreatic Neoplasms/genetics
  • Promoter Regions, Genetic/genetics
  • Von Hippel-Lindau Tumor Suppressor Protein/genetics

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