Yoon JH, Park YG, Nam SW, et al. - The value of serum gastrokine 1 (GKN1) protein as a diagnostic biomarker specific to gastric cancer was investigated in this study. Compared with the levels in gastric cancer patients, the serum concentration of GKN1 in healthy individuals was significantly higher. For gastric cancer, serum GKN1 protein yielded a sensitivity of 91.2% and a specificity of 96.0% at the optimum cutoff (4.94 ng/μL). At the optimum cutoff, 0.9675 was the diagnostic accuracy of the serum GKN1 protein. Patients with advanced gastric cancer vs those with early gastric cancer had lower serum GKN1 levels. With AUC values greater than 0.94, a robust differentiation of gastric cancer from colorectal, liver, lung, breast, pancreatic, ovary, and prostatic cancers was allowed by serum GKN1 levels. Overall, findings are indicative of a promising utility of serum GKN1, as well as of its high specificity as a diagnostic biomarker for the prompt identification of early and advanced gastric cancers.