Whole Blood DNA Aberrant Methylation in Pancreatic Adenocarcinoma Shows Association with the Course of the Disease: A Pilot Study

Osman El-Maarri,Albertas Dauksa,Johannes Oldenburg,Giedrius Barauskas,Rakesh K Srivastava,Antanas Gulbinas,Juozas Pundzius

doi:10.1371/journal.pone.0037509

Osman El-Maarri, Albertas Dauksa + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0037509

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Abstract

Pancreatic tumors are usually diagnosed at an advanced stage in the progression of the disease, thus reducing the survival chances of the patients. Non-invasive early detection would greatly enhance therapy and survival rates. Toward this aim, we investigated in a pilot study the power of methylation changes in whole blood as predictive markers for the detection of pancreatic tumors. We investigated methylation levels at selected CpG sites in the CpG rich regions at the promoter regions of p16, RARbeta, TNFRSF10C, APC, ACIN1, DAPK1, 3OST2, BCL2 and CD44 in the blood of 30 pancreatic tumor patients and in the blood of 49 matching controls. In addition, we studied LINE-1 and Alu repeats using degenerate amplification approach as a surrogate marker for genome-wide methylation. The site-specific methylation measurements at selected CpG sites were done by the SIRPH method. Our results show that in the patient’s blood, tumor suppressor genes were slightly but significantly higher methylated at several CpG sites, while repeats were slightly less methylated compared to control blood. This was found to be significantly associated with higher risk for pancreatic ductal adenocarcinoma. Additionally, high methylation levels at TNFRSCF10C were associated with positive perineural spread of tumor cells, while higher methylation levels of TNFRSF10C and ACIN1 were significantly associated with shorter survival. This pilot study shows that methylation changes in blood could provide a promising method for early detection of pancreatic tumors. However, larger studies must be carried out to explore the clinical usefulness of a whole blood methylation based test for non-invasive early detection of pancreatic tumors.

Highlights

Pancreatic cancer is the fourth most common cause of cancerrelated mortality worldwide, with the majority of cases leading to death within a relatively short time [1]
Using the SIRPH protocol (SNuPE combined with ion pair reverse phase HPLC) [22,23] we measured methylation at three CpG sites, in the Alu consensus sequence, while two CpG sites were analyzed at LINE-1 repeats
At tumor suppressor genes we measured one CpG site in the p16, BCL2, DAPK1, TNFRSF10C, CD44 promoter regions, while two CpG sites were measured in the APC, 3OST2, ACIN1 and RARbeta promoter regions

Summary

Introduction

Pancreatic cancer is the fourth most common cause of cancerrelated mortality worldwide, with the majority of cases leading to death within a relatively short time [1]. Pancreatic cancer is associated with no or minimal symptoms making detection of this potentially curable malignancy difficult to achieve. The overall five year survival rate following pancreaticoduodenectomy for pancreatic cancer is as low as 15–20% [2]. Reliable, and noninvasive test with the potential to increase the rates of detection and to provide early warning for the presence of the malignancy is urgently required. Such a test would increase the rate of survival and the cure rate. Knowledge on the molecular pathogenesis of pancreatic cancer and availability of possible biomarkers with clinical value to be used for the development of such a test are limited

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