Expression of Inducible Nitric Oxide Synthase (iNOS) in Astrocytomas of Various WHO Grades with and without Malignant Progression

Serge Weis, Hella Wolf, Frank Weiner, Wolf G and Johannes Haybaeck

Division of Neuropathology, Neuromed Campus, Kepler University Hospital, School of Medicine, Johannes Kepler University, Linz, Austria
Institute of Pathology, Otto-von-Guericke University, Magdeburg, Germany
Institute of Medical Neurobiology, Otto-von-Guericke University, Magdeburg, Germany

^*Correspondance to: Serge Weis 

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Abstract:

Nitric Oxide (NO), a free radical gas implicated in a wide variety of biological processes, is generated in many mammalian cells by a family of enzymes, i.e. Nitric Oxide Synthases (NOS). Nitric oxide produced by the inducible NOS isoform (iNOS or NOS II) seems to play an important role in tumor biology showing both tumor promoter and antitumor activity. The aim of the present study was to determine the cellular localization of iNOS in astrocytoma (WHO grade II), anaplastic astrocytoma (WHO grade III) and glioblastoma (GBM) (WHO grade IV) by immunohistochemistry using commercially available antibodies, as well as to detect possible changes in astrocytomas with malignant progression compared to the non-progressive group. Positive iNOS immunostaining was detected in all samples of astrocytoma specimens, whereas non-tumorous brain tissue adjacent to the tumor did not show any iNOS positivity. The tumor tissue revealed a highly inhomogeneous staining pattern. We found uniformly stained tumor specimens and groups of markedly iNOS-positive tumor cells, besides unstained tumor tissue as well as randomly scattered individual tumor cells expressing a marked staining. Immunoreactivity was located within the cytoplasm of neoplastic astrocytes.There were no statistically significant differences among astrocytomas of WHO grades II, III, and IV, between astrocytomas with and without malignant progression. Furthermore, there was no clear correlation between the density of iNOS-immunopositive cells and survival time. Further studies will be necessary to elucidate the role of iNOS in concert with other signaling pathways played in astrocytomas in order to see how and to what extent they are functionally interrelated.

Keywords:

Inducible nitric oxide synthase (iNOS); Astrocytomas; Glioblastoma; Malignant progression

Cite the Article:

Weis S, Wolf H, Weiner F, Wolf G, Haybaeck J. Expression of Inducible Nitric Oxide Synthase (iNOS) in Astrocytomas of Various WHO Grades with and without Malignant Progression. Clin Oncol. 2017; 2: 1297.