Frequent expression of inducible nitric oxide synthase in esophageal squamous cell carcinomas

Int J Oncol. 1999 Jun;14(6):1069-73. doi: 10.3892/ijo.14.6.1069.


Nitric oxide (NO) plays important biological roles in cardiovascular, nervous and immune systems, and is synthesized by nitric oxide synthase (NOS). Intracellular NO is known to cause DNA damage as a mutagen. We examined the expression of cytokine-inducible NOS (iNOS) in human esophageal squamous cell carcinomas. Weak iNOS immunoreactivity was seen in the basal and parabasal layers of non-neoplastic esophageal stratified squamous epithelium. iNOS expression was detected in 50 (87.7%) of the 57 esophageal squamous cell carcinomas, regardless of the depth of tumor invasion, histological differentiation and lymph node status. Early-stage cancers, i.e. mucosal squamous cell carcinomas, also showed significant iNOS expression. We speculate that increased iNOS expression is associated with the carcinogenesis of human esophageal cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Squamous Cell / enzymology*
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / pathology
  • Epithelium / enzymology
  • Esophageal Neoplasms / enzymology*
  • Esophageal Neoplasms / genetics
  • Esophageal Neoplasms / pathology
  • Esophagus / enzymology
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Nitric Oxide Synthase / biosynthesis*
  • Nitric Oxide Synthase / genetics
  • Nitric Oxide Synthase Type II
  • Reverse Transcriptase Polymerase Chain Reaction


  • NOS2 protein, human
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II