in Gastric cancer is the second cause of cancer deaths after there is increasing need to develop reliable biomarkers

Full list of author information is available at the end of the articlelung cancer, and is a major health burden worldwide [1]. Despite advances in therapeutic modalities during the past decades, the prognosis at the advanced stage is still dismal, with an average 5-year survival rate of less than 20 % [2,3]. The cause of gastric cancer is multifactorial, and the prognosis varies widely in gastric cancer patients for predicting clinical outcomes and establishing new therapeutic and preventive strategies to this disease. Although a number of biomarkers have been demon-strated to be closely associated with poor prognosis of gastric cancer patients [5-9], most of them are concerned with the roles of nuclear DNA (nDNA) alterations in gastric tumorigenesis [10-14]. These genetic or epigenetic alterations cause gain-of-function in oncogenes and loss-of-function in tumor suppressor genes [15,16], however, * Correspondence