High expression of proenkephalin is associated with favorable outcomes in patients with gastrointestinal stromal tumors

Defeng Tang,1,2 Tianlong Lin,1 Yangyang Wang,1 Hui Cao11Department of Gastrointestinal Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, People’s Republic of China; 2Department of General Surgery, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200336, People’s Republic of ChinaPurpose: The aim of this study was to elucidate the prognostic value of proenkephalin (PENK) in gastrointestinal stromal tumors (GISTs).Patients and methods: We collected data on 268 eligible postoperative patients diagnosed with GIST between January 1, 2002, and December 31, 2011. PENK expression was detected in GIST tissues classified using the United States National Institutes of Health (NIH) risk classification system. The associations between high PENK expression and the clinicopathological characteristics were assessed. Overall survival (OS) and recurrence-free survival (RFS) were estimated by Kaplan–Meier analysis, and the log-rank test was used to compare the differences between groups. Univariate and multivariate Cox regression analyses were conducted to assess the prognostic value of PENK in GIST patients.Results: High PENK expression was more common in the low- and intermediate-risk GIST groups compared with the high-risk group (P