Electroporation therapy of human larynx tumors HEp-2 implanted in nude mice

Background: Electroporation therapy (EPT) uses reversible membrane permeabilization of cells by electrical pulses for intracellular delivery of poorly permeating drugs like bleomycin. This treatment modality has been found to significantly increase the cytotoxic effect of the drug to tumor cells. Methods: Tumors of human epidermoid carcinoma of larynx (HEp-2) were xenografted subcutaneously in nude mice. EPT consisted of intratumoral injection of bleomycin followed by 6 x 100 mu s square wave electrical pulses of 1130 Volts. The effect of treatment on tumor growth was monitored over a period of 67 days. Results: Complete regression of the tumors was observed in 83 % of the treated mice 67 days after treatment. These findings were confirmed by histopathological analysis of tumor samples from the treated sites, which showed complete absence of tumor cells. Conclusions: The results indicate that electroporation therapy is very effective and has potential for treating laryngeal tumors clinically.