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Immunohistochemical staining for DNA topoisomerase II in frozen and formalin-fixed paraffin-embedded human tissues
J A Holden1, G W Snow, S L Perkins
1Department of Pathology, University of Utah, Salt Lake City.
Abstract:
DNA topoisomerase II is the molecular target of several clinically useful chemotherapeutic drugs. The sensitivity of cells to drugs that target topoisomerase II is dependent on the cellular content of this enzyme. Drug-sensitive cells have elevated amounts of type II topoisomerase. To determine relative amounts of enzyme in malignant neoplasms, we developed an in situ immunohistochemical stain for topoisomerase II. The stain uses either polyclonal or monoclonal antibodies produced against the alpha isoform of the enzyme. Staining can be done on both frozen and formalin-fixed, paraffin-embedded tissues. By using this immunostain, we found marked differences in enzyme content in several human malignancies.
Insights
Drug sensitivity in cancer cells relies on DNA topoisomerase II levels. Researchers developed an immunohistochemical stain to measure this enzyme in tumors, revealing significant variations in human malignancies.
Area of Science:
- Molecular Biology
- Oncology
- Biochemistry
Background:
- DNA topoisomerase II is a key target for chemotherapy drugs.
- Cellular sensitivity to these drugs correlates with the enzyme's content.
- Drug-sensitive cells exhibit higher levels of DNA topoisomerase II.
Purpose of the Study:
- To quantify DNA topoisomerase II levels in malignant neoplasms.
- To develop a reliable method for assessing enzyme content in human tumors.
Main Methods:
- Development of an in situ immunohistochemical stain for DNA topoisomerase II.
- Utilized polyclonal and monoclonal antibodies targeting the alpha isoform.
- Applied the stain to both frozen and formalin-fixed, paraffin-embedded tissues.
Main Results:
- Successfully developed and applied an immunohistochemical stain for DNA topoisomerase II.
- Demonstrated marked differences in enzyme content across various human malignancies.
- The stain is effective on different tissue preservation methods.
Conclusions:
- The developed immunostain allows for the assessment of DNA topoisomerase II levels in tumors.
- Significant variability in enzyme content exists among human malignancies.
- This method can aid in understanding drug sensitivity and tumor heterogeneity.