SOX9 is expressed in normal stomach, intestinal metaplasia, and gastric carcinoma in humans

Background SOX9 is a marker for stem cells in the intestine and overexpression of SOX9 is found in some types of cancer. However, the expression of SOX9 in normal stomach, precancerous intestinal metaplasia, and gastric carcinoma has not yet been clarified. This study aimed to investigate SOX9 expression in the corpus and pyloric regions of the normal human stomach, premalignant intestinal metaplasia, and gastric carcinoma by using immunohistochemistry. Methods We evaluated SOX9 expression in 46 clinical samples (early gastric well-differentiated adenocarcinoma including surrounding intestinal metaplasia) resected under esophagogastroduodenoscopy. Results A small amount of SOX9 was expressed in the neck/isthmus of the corpus region and SOX9 expression was predominantly restricted to the neck/isthmus of the pyloric region in normal human stomach. In the intestinal metaplastic mucosa, SOX9- and PCNA-positive cells were located at the base of the intestinal metaplastic mucosa. Almost all of the gastric carcinoma cells expressed SOX9. Conclusion SOX9 is expressed in intestinal metaplasia and gastric carcinoma in humans.