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Topoisomerase II-alpha expression in melanocytic nevi and malignant melanoma
1Division of Dermatopathology and Dermatology, Samuel S. Stratton Veteran Administration Medical Center and Albany Medical College, New York 12208, USA.
Abstract:
Malignant melanoma (MM) is considered to be a chemotherapy-refractory tumor. New anti-cancer drugs (e.g. etoposide) that target DNA topoisomerases (e.g. topoisomerase II-alpha (topo IIalpha)) show activity against a wide variety of solid tumors. In this study, we investigated the frequency and rate of labeling for topo IIalpha in 163 MMs (primary and metastatic) and 67 melanocytic nevi to determine whether topo IIalpha expression is elevated in MM. Primary MM exhibited significantly more frequent topo IIalpha expression compared to benign nevi (86% vs. 56%, p=0.0001). The rate of topo IIalpha labeling in dysplastic melanocytic nevi, radial growth phase MM, vertical growth phase MM and metastatic MM revealed significant differences amongst groups and a positive covariance with advancing stage (means: 0.3, 0.5, 5, and 8 '+' cells/hpf, respectively; r=0.3, all p < or = 0.02). Topo IIalpha labeling significantly correlated with increasing mitotic activity, depth of invasion and Clark's level, diminishing tumor infiltrating lymphocytes, and poor outcome (all p < or = 0.01) in primary MM. For metastatic MM, a minority (30%) exhibited marked elevation of topo IIalpha expression. These findings indicate topo IIalpha as a potential therapeutic target and marker for MM. Immunohistochemical analysis of disseminated MM may allow for correlation with clinical response and enable selection of candidates sensitive for specific chemotherapy.
Insights
Malignant melanoma (MM) shows elevated expression of topoisomerase II-alpha (topo IIalpha), a DNA-targeting enzyme. This finding suggests topo IIalpha is a potential therapeutic target and marker for melanoma treatment.
Area of Science:
- Oncology
- Molecular Biology
- Dermatopathology
Background:
- Malignant melanoma (MM) is often resistant to chemotherapy.
- DNA topoisomerases, such as topoisomerase II-alpha (topo IIalpha), are targets for novel anti-cancer drugs.
- Understanding topo IIalpha expression in melanoma is crucial for identifying new therapeutic strategies.
Purpose of the Study:
- To investigate the frequency and rate of topo IIalpha expression in primary and metastatic MM.
- To compare topo IIalpha expression between MM and benign melanocytic nevi.
- To determine the correlation of topo IIalpha expression with melanoma stage and clinical parameters.
Main Methods:
- Immunohistochemical analysis of topo IIalpha labeling in 163 MM samples (primary and metastatic) and 67 melanocytic nevi.
- Quantification of topo IIalpha labeling index and rate.
- Statistical analysis to assess correlations with clinicopathological features and outcome.
Main Results:
- Significantly higher topo IIalpha expression in primary MM (86%) compared to benign nevi (56%).
- Topo IIalpha labeling rate increased with advancing melanoma stage, from radial growth phase to metastatic disease.
- Topo IIalpha expression correlated with increased mitotic activity, invasion depth, Clark's level, and poorer outcome in primary MM.
Conclusions:
- Topo IIalpha is significantly upregulated in malignant melanoma, indicating its potential as a therapeutic target.
- Topo IIalpha expression serves as a potential biomarker for melanoma progression and patient prognosis.
- Immunohistochemical analysis of topo IIalpha in metastatic melanoma may guide patient selection for specific chemotherapy regimens.