Cyclin D1 expression and HHV8 in Kaposi sarcoma

Background-Human herpesvirus 8 (HHV8) appears to be the agent responsible f or Kaposi sarcoma. The mechanism remains undetermined but may involve cell, cycle regulating genes including D type cyclins which are pivotal in cell cycle progression. Recent HHV8 genetic analysis has revealed the presence o f a v-cyclin which is homologous to D type cyclins. Aims-First, to assess whether there is an independent relation between endo genous cyclin D1 expression in Kaposi sarcoma and HHV8 status; second to de termine whether v-cyclin mRNA expression varies with Kaposi sarcoma stage. Methods-Cyclin D1 immunohistochemistry was performed on 17 paraffin embedde d Kaposi sarcoma samples from 16 patients. HHV8 status was assessed in 15 o f these using nested polymerase chain reaction (PCR) to ORF 26 and the newl y described technique of TaqMan(R) PCR. An additional 10 fresh Kaposi sarco ma samples (early and nodular) were examined for HHV8 v-cyclin RNA, Results-One ease, which did not contain amplifiable HHV8, showed strong cyc lin D1 staining. The remaining cases were negative or weakly staining; v-cy clin transcript load was higher in early Kaposi sarcoma, Conclusions-While endogenous cyclin D1 expression is independent of HHV8 st atus, v-cyclin transcription is higher in early lesions, supporting the "vi ral hit" hypothesis. Background-Human herpesvirus sis has revealed the pres ence of a v-cyclin which is homologous to D type cyclins. with Kaposi sarco ma stage. for HHV8 v-cyclin RNA, coma. hypothesis.