Epigenteic Alteration of DOK7 Gene CpG Island in Blood Leukocyte of Patients with Gastric Cancer and Intestinal Methaplasia.

Background: Intestinal metaplasia (IM) is a benign lesion with no serious concern for patients' health. On the other hand, gastric cancer (GC) is a malignant lesion that has to be differentially diagnosed from benign intestinal metaplasia. Epigenetic modifications have been suggested to play an important role in cancer initiation and development, and they have been investigated as a reliable biomarker tool even for early cancer diagnosis. Whole blood leucocytes (WBC) are potentially the most accessible tissue for cancer early diagnosis, especially for GC, which is hard to diagnose in the early stage.

Objective: This study aims to investigate the methylation status of DOK7 gene CpG island in blood leukocytes of patients with IM and GC compared to normal control groups.

Material and method: DNA was extracted from the whole blood of 30 IM patients, 30 GC patients, and 34 normal controls samples, and MSRE-PCR was utilized to evaluate the loci methylation status.

Results: Significant hypermethylation of DOK7 gene CpG has been observed in GC 88.1 % (p < 0.001) and IM 66.0 % (p = 0.03) in comparison to the normal control group 56.8%. A cutoff upper than 84.5 % of hypermethylation is considered as a presence of gastric cancer malignant lesions.

Conclusions: This is the first reported on hypermethylation in DOK7 CPG in blood leukocytes of patients with GC and IM and establishing a laboratory blood based test that may be useful as a novel biomarker test in the early diagnosis and screaning of GC and IM.