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Glutathione S ‐Transferase π in Squamous Cell Carcinoma of the Head and Neck
Author(s) -
Bentz Brandon G.,
Kenneth Haines G.,
Radosevich James A.
Publication year - 2000
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200010000-00013
Subject(s) - pathology , immunostaining , nitrotyrosine , glutathione , immunohistochemistry , head and neck squamous cell carcinoma , nitric oxide synthase , glutathione s transferase , squamous carcinoma , microbiology and biotechnology , biology , chemistry , head and neck cancer , cancer , cancer research , nitric oxide , carcinoma , medicine , biochemistry , endocrinology , enzyme , genetics
Objectives/Hypothesis Oxidative/reductive (redox) DNA damage from radical species such as nitric oxide (NO·) are increasingly being implicated in the development of cancer. Moreover, redox‐protective cellular mechanisms, such as glutathione S ‐transferase, may determine cellular susceptibility to this redox‐mediated damage. Methods Formalin‐fixed, paraffin‐embedded tissue samples of 11 normal oral mucosa, 15 reactive/dysplastic lesions, and 131 head and neck squamous cell carcinomas (HNSCCs) were immunohistochemically stained using a polyclonal antibody against glutathione S ‐transferase π (GST‐π). Slides were reviewed in a blinded fashion by the study pathologist (g.k.h.) and intensity was graded, noting the pattern of immunostaining. These staining characteristics were compared with those obtained using monoclonal antibodies against endothelial constitutive nitric oxide synthase (ecNOS) and nitrotyrosine, a marker of NO·'s pathological nitrosylation of proteins on serial sections of the same tissue. Patient charts were reviewed and clinical data collected. Results The expression of GST‐π was significantly increased in reactive/dysplastic and HNSCC samples compared with normal squamous mucosa ( P < .001 for both). Furthermore, among the carcinomas the expression of GST‐π was significantly increased in higher‐grade lesions ( P < .02). The expression of GST‐π correlated highly with the expression of ecNOS and nitrotyrosine ( P < .0001 for both). Conclusions These findings demonstrate that GST‐π is upregulated in conjunction with the NO·‐generating ecNOS isoform and implicate GST‐π in protecting HNSCC from the cytotoxic effects of high concentrations of NO· found in the tumor bed.