Human epididymis protein 4 is up-regulated in gastric and pancreatic adenocarcinomas

Abstract

Upper gastrointestinal neoplasia in the esophagus, stomach, and pancreas is associated with the formation of preneoplastic metaplasias. We have previously reported the up-regulation of human epididymis protein 4 (HE4) in all metaplasias in the stomach of humans and mice. We have now sought to evaluate the expression of HE4 in metaplasias/preneoplastic precursors and cancers of the human stomach, pancreas, and esophagus. Tissue microarrays for gastric cancers, pancreatic cancers, and esophageal adenocarcinoma were stained with antibodies against HE4. Immunostaining was quantified by digital imaging, and the results were evaluated to assess the expression in metaplasias, the expression in cancer pathological subtypes, and the effects of expression on survival in patients with cancer. In patients with gastric cancer from Korea, HE4 was detected in 74% of intestinal and 90% of diffuse cancers, whereas in a gastric cancer cohort from Johns Hopkins, HE4 was detected in 74% of intestinal-type and 92% of diffuse cancers. Nevertheless, in both cohorts, there was no impact of HE4 expression on overall survival. In the esophagus, we observed the expression of HE4 in scattered endocrine cells within Barrett esophagus samples, but Barrett columnar metaplasias and HE4 were detected in only 2% of esophageal adenocarcinomas. Finally, in the pancreas, HE4 expression was not observed in pancreatic intraepithelial neoplasia lesions, but 46.8% of pancreatic adenocarcinomas expressed HE4. Still, we did not observe any influence of HE4 expression on survival. The results suggest that HE4 is up-regulated during gastric and pancreatic carcinogenesis.

Figure 1. Immunohistochemical staining of HE4 in intestinal metaplasia and gastric cancers

A. HE4 staining in intestinal metaplasia. B, C. HE4 staining in gastric cancer specimens from Korean patient arrays. D. HE4 staining in intestinal type gastric cancer specimen from Johns Hopkins arrays. Higher magnification views are shown at right. All scale bars are 100 µm.

Figure 2. HE4 in normal esophageal tissue and Barrett’s epithelium

HE4 immunostaining was performed in human esophageal tissues.(A) Normal esophageal squamous epithelium showed no staining for HE4. (B) Barrett’s epithelium without HE4 staining. C–E. Barrett’s epithelium with HE4 staining in the bases of some glands. F. Dual immunofluorescence staining for HE4 and chromograninA in Barrett’s epithelium. HE4 immunoreactive cells in the Barrett’s epithelium were also immunoreactive for chromogranin A (dual label merged image at right: HE4 pseudocolored red and chromogranin A pseudocolored green with direct overlap seen as yellow), indicating that they are enteroendocrine cells. All scale bars are 100 µm.

Figure 3. Immunohistochemical staining of HE4 in normal pancreas, PanIN and pancreatic cancer

A. HE4 staining in normal pancreas. Note strong staining in a pancreatic islet. B. HE4 staining in a low grade PanIN lesion. C. HE4 staining in a high grade PanIN lesion. D. HE4 staining in pancreatic adenocarcinoma from same patient with PanIN lesion in C. E,F. HE4 staining in pancreatic adenocarcinomas. Higher magnification views are shown at right. All scale bars are 100 µm.

Figure 4. Outcomes in pancreatic and gastric adenocarcinoma patients associated with HE4 expression

Samples in all groups were classified based on no detectable HE4 staining or low or high staining based on the median staining observed among positively stained samples. Kaplan-Meier survival statistics were calculated for all groups. A. Survival in pancreatic cancer patients identified at Johns Hopkins. B. Survival in gastric cancer patients identified at Seoul National University, Korea. C. Survival in gastric cancer patients resected at Johns Hopkins.