Pepsinogens 1 and 2 are usually written as pepsinogens I and II. They can indicate gastric diseases and ectopic pepsinogen-secreting tumors. 1. Gastric diseases: Pepsinogen I and II are precursors of pepsin secreted by the master cells of the stomach, which can be activated into pepsin under the action of gastric acid and participate in food digestion. Elevation of pepsinogen I and II represents the increase of secretion function of master cells, which leads to the damage of gastric mucosa and increase of gastric acid secretion, and usually suggests gastritis, Helicobacter pylori infection, gastric ulcer and so on; Decrease of pepsinogen I and II represents the decrease of secretion function of master cells, and usually suggests atrophic gastritis, gastric cancer and other diseases. 2. Tumors with ectopic secretion of pepsinogen: prostate cancer, breast cancer, ovarian cancer and other cancers may ectopically secrete pepsinogen and elevate the phenomenon of pepsinogen I and II. If the phenomenon of pepsinogen I and II occurs, further examination of gastroscopy, Helicobacter pylori breath test, tumor markers, abdominal ultrasound and other items are needed to find out the cause of the problem and then treat it under the guidance of doctors.