[Histopathological examination in gastroesophageal reflux disease (GERD)]

We performed an immunohistochemical analysis of cell cycle-regulating protein (p21, p27 and Ki67) expression in endoscopic biopsy samples from the patients with gastroesophageal reflux disease (GERD) using angled-biopsy forceps. Inflammatory cell accumulation into the lamina propria was detected even in patients with modified Los Angeles (IA) system grades N and/or M. In grade N and M patients with no changes in the epithelium, the area of p21, p27 and Ki67 positive cells was expanded compared to normal mucosa. The area of p21, p27 and Ki67 positive cells tended to expand upward in the epithelium with GERD severity based on the LA classification grading. These indicate that inflammatory cell infiltration into the lamina propria is initial histological change of GERD.