Immunohistochemical analysis of cell cycle-regulating-protein (p21, p27, and Ki-67) expression in gastroesophageal reflux disease

Background The aim of this study was to carry out an immunohistochemical analysis of cell cycle-regulating-protein (p21, p27, and Ki-67) expression in endoscopic biopsy samples obtained using angled biopsy forceps. Methods. The study was based on the examination of endoscopic esophageal biopsy specimens obtained from 46 patients with evidence of reflux and from 10 normal control subjects without clinical reflux. Results. The percentage of samples containing the lamina propria was 5.7% using standard forceps (n = 53) and 83.3% using the angled forceps (n = 67). The use of angled forceps allowed the detection of inflammatory cell accumulation in the lamina propria even in patients with modified Los Angeles (LA) system grades N and M. In normal esophageal mucosa, Ki-67-positive cells were detected within the lower parts of the basal zone, and p21- and p27-positive cells were not detected. In samples from grade N and M patients, no histological changes were detectable by standard H&E staining. However, the area of Ki-67-positive cells was slightly expanded compared with normal mucosa, and p21- and p27-positive cells were clearly detectable from the lower to middle part of the epithelium. The area of Ki-67-, p21-, and p27-positive cells tended to expand upward in the epithelium with gastroesophageal reflux disease (GERD) severity based on the LA classification grading. Conclusions. The use of angled biopsy forceps allows the evaluation of inflammatory responses at the level of the lamina propria and makes it possible to assess the expression of cell cycle-regulating proteins in the entire epithelium. The evaluation of these responses may be helpful in the diagnosis of endoscopically negative GERD.