DNA topoisomerase I and IIα expression in penile carcinomas: assessing potential tumour chemosensitivity

Authors


Daniel Berney, Barts and the London, Queen Mary’s School of Medicine and Dentistry – Department of Cellular Pathology, The Royal London Hospital 80 Newark Street, London E1 2ES, UK.
e-mail: danberney@hotmail.com

Abstract

OBJECTIVE

To examine the tissue expression of DNA topoisomerase I (Topo I) and IIα (Topo II), to pursue the possibility of future chemotherapy regimens for squamous cell carcinoma of the penis (SCCP), as high expression of Topo I might indicate sensitivity to the camptothecins, whereas high Topo II might indicate sensitivity to etoposide.

PATIENTS AND METHODS

In all, 73 patients with SCCP were reviewed and then tissue samples microarrayed. These were then stained with immunohistochemistry for Topo I, Topo II and Ki-67. Tumour stage, grade and type were available.

RESULTS

Topo II showed a strong positive correlation with the proliferation index as measured by Ki-67 (P < 0.001) but no correlation with Topo I. There were also strong correlations between tumour grade and Ki-67, and Topo II expression (both P < 0.001). Tumour type was also strongly correlated with Topo II and Ki-67 expression, with the highest expression in basaloid carcinomas and the lowest in verrucous carcinomas. However, Topo I expression was not correlated with any other tumour variable.

CONCLUSION

The expression of Topo I is grade- and type-independent, and chemotherapy using the camptothecins is unlikely to be effective. The strong positivity of Topo II in high-grade and basaloid SCCPs suggests that treatment with etoposide or other Topo II ‘poisons’ might be a better target for future clinical trials.

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