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Oligodendroglioma: HMB-45 positivity using catalyzed signal amplification method: an immunohistochemical (HMB-45,
G L Taddei1, L Arganini, M R Raspollini
1Department of Human Pathology and Oncology, University of Florence, Italy. gl.taddei@unifi.it
Abstract:
Although melanin synthesis and the presence of melanosomes are exceptionally reported in nervous system tumors, there is no record of melanotic oligodendrogliomas in the literature. The purpose of the current study was to evaluate whether melanosomes are immunohistochemically and ultrastructurally detectable in nonmelanotic oligodendrogliomas and to verify whether these data are related to prognosis. Thirty surgical specimens (19 primary lesions and 11 recurrences) from 19 patients were examined. Median survival was 80 months. Immunohistochemical studies were performed using the monoclonal antibodies HMB-45, CD31. Mib-1, and p53. Using catalyzed signal amplification (CSA), HMB-45 positivity was noticed in 3 (10%) of the oligodendrogliomas being studied. No correlation with survival was found. Ultrastructural examination displayed the presence of melanosomelike structures. Tumor vascularization, estimated by means of CD31 antibody, was increased in 6 of 19 primary lesions but there was no significant correlation with survival. Nine of the19 primary lesions were p53 negative. In these cases, survival was longer than in p53-positive tumors (P = 0.0213). Proliferation rate, evaluated with Mib-1, was unrelated to survival, but proved greater in recurrences (10 of 11 cases) than in primary tumors (7 of 19 lesions; P = 0.007).
Insights
This study investigated melanosomes in oligodendrogliomas, finding melanosomelike structures ultrastructurally. While HMB-45 positivity was rare, p53 negativity correlated with longer survival in these brain tumors.
Area of Science:
- Neuro-oncology
- Cell Biology
- Tumor Pathology
Background:
- Melanin synthesis and melanosomes are rarely reported in nervous system tumors.
- Melanotic oligodendrogliomas have not been previously documented in medical literature.
Purpose of the Study:
- To determine if melanosomes are detectable in nonmelanotic oligodendrogliomas using immunohistochemistry and ultrastructural analysis.
- To assess the prognostic significance of melanosome presence and other markers in oligodendrogliomas.
Main Methods:
- Examined 30 surgical specimens (19 primary, 11 recurrent) from 19 oligodendroglioma patients.
- Utilized immunohistochemistry with antibodies HMB-45, CD31, Mib-1, and p53.
- Performed ultrastructural examination for melanosomelike structures.
Main Results:
- HMB-45 positivity (melanosome marker) was found in 10% of oligodendrogliomas, with no survival correlation.
- Ultrastructural analysis revealed melanosomelike structures.
- p53-negative primary oligodendrogliomas showed significantly longer survival (P = 0.0213).
- Tumor vascularization (CD31) and proliferation rate (Mib-1) did not correlate with survival, though Mib-1 was higher in recurrences.
Conclusions:
- Melanosomelike structures can be ultrastructurally identified in oligodendrogliomas.
- p53 negativity is a favorable prognostic indicator in oligodendroglioma patients.
- Further research is needed to understand the role and origin of these structures in brain tumors.