PGP9.5 overexpression in esophageal squamous cell carcinoma.

BACKGROUND/AIMS PGP9.5 is a ubiquitin hydrolase widely expressed in neuronal tissue at all stages of neuronal differentiation and has been used as a neuroendocrine marker. Recently, it has been proved that PGP9.5 expression was highly observed in squamous cell carcinoma of lung cancer, suggesting that it might be a tumor marker for squamous cell carcinoma. To better characterize its role in digestive tract cancers, we examined PGP9.5 expression retrospectively in esophageal cancers. METHODOLOGY We examined PGP9.5 expression retrospectively in 40 resected esophageal cancers (squamous cell carcinoma) and 10 gastric cancers (adenocarcinoma) using immunohistochemistry. RESULTS Of 40 esophageal cancer specimens, 19 (48%) exhibited positive staining with PGP9.5 in most tumor cells, while no PGP9.5 expression was observed in any of the 10 gastric cancers. CONCLUSIONS Although the precise mechanism underlying the effect of PGP9.5 on oncogenicity remains to be proven, it was confirmed that it may be a potential marker for esophageal squamous cell carcinoma.