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Updated: Jul 18, 2026

Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells
08:32

Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells

Published on: March 16, 2017

Sarcomas often express constitutive nitric oxide synthases (NOS) but infrequently inducible NOS

Isabela W Cunha1, Ademar Lopes, Roberto Falzoni

  • 1Department of Anatomic Pathology, Medical and Research Centre, Hospital do Cancer A. C. Camargo, São Paulo, Brazil. iwcancer@hcancer.org.br

Applied Immunohistochemistry & Molecular Morphology : AIMM
|November 24, 2006
PubMed

Insights

Nitric oxide synthases (NOS) are commonly expressed in sarcomas, particularly constitutive isoforms like nNOS. Inducible NOS (iNOS) expression is less common but found in specific sarcoma types, warranting further clinical investigation.

Area of Science:

  • Oncology
  • Molecular Biology
  • Biochemistry

Background:

  • Nitric oxide (NO) exhibits dual roles in tumor progression, acting as both a pro-tumor and anti-tumor agent.
  • Nitric oxide is synthesized by three main isoforms of nitric oxide synthases (NOS): neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS).
  • While NOS expression is documented in epithelial tumors, its presence in sarcomas remains largely uninvestigated.

Purpose of the Study:

  • To investigate the expression patterns of nNOS, eNOS, and iNOS in a diverse cohort of human sarcoma specimens.
  • To identify specific sarcoma subtypes that exhibit significant expression of different NOS isoforms.
  • To lay the groundwork for understanding the potential clinical relevance of NOS and NO in sarcoma biology.

Main Methods:

  • Utilized tissue array technology to analyze NOS expression in 97 diverse sarcoma cases.
  • Performed immunohistochemical staining to detect the presence and intensity of nNOS, eNOS, and iNOS.
  • Quantified and categorized NOS expression levels across different sarcoma subtypes.

Main Results:

  • A high prevalence of nNOS expression (86.6%) was observed across most sarcomas, with notable exceptions in chondrosarcomas and liposarcomas.
  • eNOS immunostaining was detected in 44.4% of cases, with strong signals predominantly in angiosarcomas, chondrosarcomas, alveolar soft part sarcomas, and synovial sarcomas.
  • iNOS expression was less frequent, with strong signals in 9.3% and weak signals in 26.8% of cases, particularly noted in malignant peripheral nerve sheath tumors, liposarcomas, and synovial sarcomas.

Conclusions:

  • Sarcomas generally exhibit common expression of constitutive NOS isoforms, primarily nNOS.
  • Inducible NOS (iNOS) expression is restricted to a subset of sarcoma types, suggesting a potential role in specific tumor microenvironments.
  • Further research is essential to elucidate the clinical significance of NOS expression and NO production in sarcomas.

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