A case of gastric cancer with high pepsinogen II levels in both serum and ascites

The first case of gastric cancer in which pepsinogen (PG) II levels were found to be extremely high not only in the serum but also in the ascites, with values of 603 ng/mL and 1910 ng/mL, respectively, is reported. Pepsinogen I and PG II are normally secreted into the gastric lumen and only 1% of the amount secreted enters the circulation. Although gastric cancer cells are found to produce PG II more often than PG I, elevated PG values in serum are extremely rare, and only one case has ever been reported. That patient had extremely high serum levels of PG I and PG II at the time of gastric cancer relapse. Pepsinogen has never been reported in the ascites and thus nothing is known about the mechanism of entry into the ascites. In this case report, we postulate two mechanisms to explain the increased PG II in the ascites: (i) a high level of serum PG II infiltrated the ascites and caused elevation of PG II in the ascites; or (ii) disseminated cancer cells directly produced PG II and it elevated PG II levels in the ascites.