A plasma pepsinogen 1 (PG1) concentration <50 ng ml–1 (15% of cases) was associated with a significantly increased risk of gastric cancer (OR 4.23; (95% CI: 1.86–9.63), whereas a plasma pepsinogen 2 (PG2) concentration >6.6 ng ml–1 (75% of cases) was also associated with a significantly increased risk of gastric cancer (OR 3.62; (95% CI: 1.85–7.09). Here, DLK1 is linked to gastric cancer.