PCR analysis of OSSN for detection of human viruses. A. Representative PCR analysis of tumor virus detection from OSSN tumor samples. For EBV PCR, LCL-2 105 cells which contain 20-50 copies of EBV per genome were used as positive control and distilled water as control for PCR mix. For HPV, Hela 105 cells which contain 10-20 copies of HPV-18 per genome were used as positive control and distilled water as control for PCR mix. Similarly for KSHV we used BCBL1 cells which contain 30-50 copies of KSHV per genome as positive control and distilled water as control for PCR mix. The PCR products are shown after electrophoresis on a 3% agarose gel containing 100 ng/ml ethidium bromide. PCR product size for each virus type is shown on the right side. We show representative gels showing the PCR results of which EBV was detected in 83% of the samples, HPV in 75% of the samples, KSHV in 70% of the samples and CMV in 61% of the samples. We did not detect JC and BK virus in any sample. B. Representative point mutations in HPV-L1 nucleotide and amino acid sequence variation in OSSN biopsies. We detected HPV-16, 18, 45, 39, and 68 isolates. As shown, the changes were mainly missense and nonsense mutations. C. Shows the primer sequences used in the PCR analysis of the oncogenic viruses in OSSN and pterygia tissues and probes used for in situ hybridization.