THYMIDINE PHOSPHORYLASE EXPRESSION IN KAPOSI-SARCOMA

Aims-To examine the immunohistochemical distribution of thymidine phos phorylase (TP) in all clinicopathological subtypes of Kaposi sarcoma. Methods-Thirty two biopsy specimens of Kaposi sarcoma (29 patients) we re studied. Six of these patients represented classic, six endemic, ei ght HIV associated, seven post-immunosuppression/transplant related, a nd two unclassifed variants of Kaposi sarcoma. The average age was 49 years (range 22-83 years) and the male: female ratio 24:5. Four sample s of angiosarcoma and one of spindle cell haemangioendothelioma were s tained in parallel. All specimens were fixed in formalin, embedded in paraffin wax and processed routinely. Immunohistochemistry was carried out using an antibody directed against CD31 (JC70) and the monoclonal antibody P-GF.44C against TP. Results-All biopsy specimens showed imm unoexpression for TP. The spindle cell component stained more strongly than newly formed endothelium lined vessels and normal, resident vess els at a distance from the lesions. Conclusions-The strong immunoexpre ssion of TP suggests up-regulation of TF and a role for TP in angiogen esis in Kaposi sarcoma. The mechanism for the up-regulation of TP rema ins unknown, but viral infections may trigger it. The differential sta ining of the various cell components of Kaposi sarcoma also suggest th at TP either plays a role in the differentiation and maturation of Kap osi sarcoma or is a reflection of such changes.