Upregulated expression of G9a is correlated with poor prognosis of gastric cancer patients

Abstract

Abstract As one of the most serious cancers, gastric cancer (GC) represents the third leading cause of malignancy-related deaths. G9a is a histone lysine methyltransferase and has been reported to be involved in the progression of some human cancers. In the present study, we aimed to explore the expression patterns and clinical value of G9a in GC patients. The expression of G9a in 142 paired GC tissues and adjacent non-cancerous tissues (no less than 5\u200acm from tumor edge) was examined with quantitative real-time polymerase chain reaction (qRT-PCR). To estimate the association of G9a expression with clinical characteristics of GC patients, Chi-square test and t test were conducted. Kaplan–Meier survival and multivariate Cox regression analyses were performed to explore the prognostic value of G9a in GC. Upregulated expression of G9a was found in GC tissues compared with noncancerous tissues (P\u200a<\u200a.001). Elevated G9a expression was significantly correlated with patients’ lymph node metastasis (P\u200a=\u200a.007) and TNM stage (P\u200a<\u200a.001). Kaplan–Meier survival curves demonstrated that patients with high G9a expression had shorter survival time than those with low expression (log-rank test, P\u200a<\u200a.05), reaching a median OS of 24 months. According to the results of Cox regression, G9a could be considered as an independent prognostic biomarker in patients with GC (HR\u200a=\u200a3.912, 95% CI\u200a=\u200a2.213–6.915, P\u200a<\u200a.001). Additionally, the diagnosis cut-off value of G9a in GC patients was 1.515. Taken together, G9a expression was upregulated in GC tissues and could be an effective prognostic biomarker for GC.