H. Tanaka et al., Frequent expression of inducible nitric oxide synthase in esophageal squamous cell carcinomas, INT J ONCOL, 14(6), 1999, pp. 1069-1073
Nitric oxide (NO) plays important biological roles in cardiovascular, nervo
us and immune systems, and is synthesized by nitric oxide synthase (NOS). I
ntracellular NO is known to cause DNA damage as a mutagen. We examined the
expression of cytokine-inducible NOS (iNOS) in human esophageal squamous ce
ll carcinomas. Weak iNOS immunoreactivity was seen in the basal and parabas
al layers of nonneoplastic esophageal stratified squamous epithelium. iNOS
expression was detected in 50 (87.7%) of the 57 esophageal squamous cell ca
rcinomas, regardless of the depth of tumor invasion, histological different
iation and lymph node status. Early-stage cancers, i.e, mucosal squamous ce
ll carcinomas, also showed significant iNOS expression. We speculate that i
ncreased iNOS expression is associated with the carcinogenesis of human eso
phageal cancer.