Scenario
Doug was a newly single 42-year-old man, whose reentry into thedating world led to a few casual sexual encounters with women hemet while out in bars.

After 8 months apart, Doug and his wife reconciled. He decidedit would be best not to mention the other women he had intercoursewith because he was pretty sure his wife would get upset eventhough they were not together at the time.

Signs and symptoms
Several months later, during a dentist’s appointment, the hygienistnoted what looked like a series of small bumps on the back and sideof Doug’s tongue, which had not been noted in his chart before.

At his next visit, the bumps had expanded into lesions and Dougmentioned them as a concern. The dentist noticed that his tonsil onthe side of the tongue lesions was swollen, as were the lymphnodes. He prescribed an antibiotic, which Doug took.

The lesions didn’t get better but they also got no worse. A fewweeks later Doug developed a stubborn sore throat, so he went tosee his family physician.

Testing
When Doug’s doctor saw the lesion at the back of his tongue, hesent Doug for an oral brush biopsy procedure.

When the biopsied tissue was stained with hematoxylin and eosinstain, the pathologist noted a well-differentiated squamous cellcarcinoma.

A second sample was obtained by scalpel biopsy and tested forhuman papillomavirus (HPV) DNA, specifically HPV-16 and HPV-18. Theresults were returned as positive for viral DNA.

Question 1: Referring to the image below obtainedby transmission electron microscopy (TEM), describe the followingcharacteristics of HPV: Enveloped or nonenveloped? Capsidsymmetry?

Question 2: HPV has a double-stranded DNAgenome. What is the Baltimore group for HPV?

Question 3: Other than genome, what criteriaare used in the Baltimore model to create distinct groups ofviruses?

Diagnosis
Doug’s diagnosis was stage IV squamous cell carcinoma.



Question 4: How is the detection of HPV DNA in thecancer tissue pertinent to this diagnosis?

Question 5: How does HPV facilitate thereplication of its genome and production of mRNA transcripts fromthe viral genes?

Treatment
Doug had surgery to remove the cancerous tissue, followed by sixmonths of radiation therapy. After two years, there was norecurrence of the cancer.

Question 6: A vaccine, Gardisil, is available toprevent HPV infection. How does a vaccine that protects against aviral infection prevent cancer?

Additional Considerations
Question 7: In a human host cell, where does theprocess of viral DNA replication occur?

Question 8: Where does translation of HPV mRNAoccur in an infected host cell?

Question 9: How are viral latency and lysogenyrelated?