human herpesvirus 6 and epstein - barr virus infections at different histopathological grades of oral squamous cell carcinomas

background: the aim of this study was to determine the prevalence and viral load of epstein–barr virus (ebv) and human herpesvirus‑6 (hhv‑6) in different histopathologic grades of oral squamous cell carcinoma (oscc). methods: forty‑five formalin‑fixed paraffin‑embedded tissue section of oscc patients were analyzed by quantitative real‑time polymerase chain reaction for detection of ebv and hhv‑6. results: the mean age of the patients was 58.6 years, 69% of whom were female, and 31% were male. overall, the positive rate for ebv and hhv‑6 were 16.7% and 27.1%, respectively; and the mean viral load ebv was 27.9 × 103 and 38.5 × 103 for hhv‑6. no correlation was demonstrated between the viral load of ebv dna ( p = 0.35) and hhv‑6 ( p = 0.38) at the different oscc histopathologic grades. conclusions: these findings neither lend support to the hypothesis that ebv and hhv‑6 are directly involved in oscc nor rule out the possibility that these viruses play an indirect role in carcinogenesis in this area.