title: Alteration of extracellular superoxide dismutase expression is associated with an aggressive phenotype of oral squamous-cell carcinoma.
abstract: Oxidative stress results in damage to cellular structures and has been linked to numerous diseases, including cancer. Extracellular superoxide dismutase (EC-SOD) is a principal enzymatic antioxidant in extracellular space. The purpose of this study was to determine whether the expression of EC-SOD protein is altered in the carcinogenetic process of oral squamous-cell carcinoma (OSCC). Immunohistochemical analysis was carried out in matched normal and tumour specimens collected from 58 OSCCs and 20 oral premalignant lesions (OPLs). Correlations between the EC-SOD expression levels and clinicopathological features of OSCC patients were evaluated by Fisher's exact test. Although EC-SOD protein was consistently expressed on the plasma membrane of cells in normal tissues, plasma membranous EC-SOD expression was lost in almost all the OSCC specimens examined (98%). Instead, positive EC-SOD expression was detected in the cytoplasmic compartments of cancerous cells in both OPLs (65%) and OSCCs (52%), together with a high incidence of lymph node metastasis (p=0.0397). These results suggest that the dysregulation of EC-SOD protein expression is a frequently occuring and early event in oral carcinogenesis, and that cytoplasmic EC-SOD may contribute to the increased aggressiveness of OSCC.
authors.affiliation: Division of Dentistry and Oral-Maxillofacial Surgery, Chiba University Hospital;
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yokoe
authors.forename: Hitomi
authors.initials: H
authors.lastname: Nomura
authors.forename: Yukio
authors.initials: Y
authors.lastname: Yamano
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Fushimi
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: Katsunori
authors.initials: K
authors.lastname: Ogawara
authors.forename: Masashi
authors.initials: M
authors.lastname: Shiiba
authors.forename: Hiroki
authors.initials: H
authors.lastname: Bukawa
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Uzawa
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Takiguchi
authors.forename: Hideki
authors.initials: H
authors.lastname: Tanzawa