Sex, HPV, and Mouth Cancers
May 2007

Certain kinds of sexual behavior were significantly associated with oropharyngeal cancer after adjustment for confounding variables (Table 2). The association with oropharyngeal cancer increased significantly with the number of vaginal-sex partners or oral-sex partners (P for trend=0.002 and 0.009, respectively) and was markedly elevated among patients with a high lifetime number of such partners (Table 2).

Oropharyngeal cancer was also strongly associated with serologic measures of exposure to HPV-16 and with the presence of oral HPV infection (Table 3). Oropharyngeal cancer was significantly associated with seropositivity for the HPV-16 L1 capsid protein, a validated measure of lifetime HPV-16 exposure (odds ratio, 32.2; 95% CI, 14.6 to 71.3).25 The presence of an oral HPV-16 infection was strongly associated with oropharyngeal cancer (odds ratio, 14.6; 95% CI, 6.3 to 36.6), as was oral infection with any of 37 HPV types (odds ratio, 12.3; 95% CI, 5.4 to 26.4) (Table 3).

To explore whether the association between sexual behaviors and oropharyngeal cancer could be explained by HPV-16 exposure, we reevaluated the associations using multivariate models after adjusting for HPV-16 L1 serologic status. In this analysis, sexual behaviors were no longer significantly associated with oropharyngeal cancer (data not shown). However, associations of sexual behaviors with oropharyngeal cancer became stronger when the analysis was restricted to patients with an HPV-16-positive tumor (Table 2). A high lifetime number of oral-sex or vaginal-sex partners, engagement in casual sex, early age at first intercourse, and infrequent use of condoms each were associated with HPV-16-positive oropharyngeal cancer (Table 2).

In the Author Discussion they say: Our data suggest that oral HPV infection is sexually acquired. Oral-genital contact was strongly associated with oropharyngeal cancer, but we cannot rule out transmission through direct mouth-to-mouth contact or other means. Certain sexual behaviors13,14 and a history of oral HPV infection7,10 were associated with an increased risk of squamous-cell carcinomas of the head and neck in previous studies in which 25% or more of the tumors from patients were positive for HPV DNA but not those in which less than 25% of the tumors from patients were positive for HPV DNA.8,9 Discrepant findings may be explained by the heterogeneity of the case populations, with variable percentages of cancer cases attributable primarily to tobacco and alcohol use, as compared with HPV infection. In our study, the heterogeneity of case patients was minimized by restricting enrollment to patients with oropharyngeal cancer, 90% of whom had tumors on the tonsil or base of the tongue.

Although HPV-16 alone accounts for more than 90% of cases of HPV-positive squamous-cell carcinomas of the head and neck,8 a more accurate and probably higher proportion might be found by testing for other types of HPV (e.g., types 18, 31, 33, and 35), which are infrequently detected in oropharyngeal cancers.

From Different Source

MOUTH CANER AND THE HUMAN PAPILLOMA VIRUS

The human papilloma virus (HPV) is one of the most common virus groups in the world to affect the skin and mucosal areas of the body. Over eighty typs of HPV have been identified. Different types of the human papillomavirus are known to infect different parts of the body. It infects the epithelial cells of skin and mucosa. The epithelial surfaces include all areas covered by skin and/or mucosa such as the mouth, throat, tongue, tonsils, vagina, penis, and anus. Infection with the virus occurs when these areas come into contact with a virus, allowing it to transfer between epithelial cells.

Warts

The most common forms of the virus produce warts (papilloma's) on the hands, arms, legs, and other areas of the skin. The wart-like growths are called condyloma tissues. Condyloma tissue appears like a small, cauliflower-type growth on the skin. These growths are usually painless, but can cause some irritation, itching, or burning. It can be treated whenever it flares up, and is non malignant. Most HPV's of this type are very common, harmless, non cancerous, and easily treatable. Genital warts are known technically as condylomata acuminatum and are generally associated with two HPV types, numbers 6 and 11 and can be sexually transmitted.

Cervical Cancer and Oral Cancer

There are other forms of HPV which are also sexually transmitted, and are a serious problem. These are; HPV-16, HPV-18, HPV-31, and HPV-45. These cancer-associated types of HPVs cause dysplastic tissue growths that usually appear flat and are nearly invisible. Dysplastic tissue is the presence of abnormal cells on the surface of the skin. Dysplasia is not cancer, but it is a tissue change seen prior to malignancy. A highly studied topic is HPV's ability to cause cervical cancer. Dysplasia can be detected on the female cervix through a Pap smear test, or seen visually using a magnifying glass called a colposcope. The most dangerous HPV's, 16 and 18, which are transmitted through sexual contact are known to cause up to 95% of cervical cancers. Now these two HPV's are also being linked to oral cancer.

A study done by Dr. No-Hee Park showed that the mouth was, at the cellular level, structurally very similar to the vagina and cervix. Both organs have the same type of epithelial cells that are the target of HPV 16 and HPV 18. The majority of oral cancers are cancers of epithelial cells, primarily squamous cell carcinomas, not unlike the cancers that affect the cervix. Dr. Park's study also showed that smoking and drinking alcohol help promote HPV invasion.. Combine tobacco and alcohol with HPV, and the epithelial cells in the mouth, and you may have the formula for the development of an oral cancer.

A recent study conducted by Dr. Maura Gillison at the Johns Hopkins Oncology Center furthered the premise that HPV is linked with certain types of oral cancer. In 25% of 253 patients diagnosed with head and neck cancers, the tissue taken from tumors was HPV positive and HPV 16 was present in 90% of these positive HPV tissues. This information helps to confirm that there is a strong link between HPV 16 and oral cancer. 25% of those diagnosed with oral cancer are non-smokers while the other 75% of those diagnosed have used tobacco in some form during their lifetimes. The research into the relationship of HPV and oral malignancies may give us clues as to the origin of cancer in those 25% of diagnosed individuals who did not smoke. Further research is being conducted into the relationship of HPV with oral cancers.

Treatments for Warts

Although there is currently no medical cure to eliminate a papillomavirus infection, the squamous intraepithelial lesions (SILs) and warts these viruses cause can be treated. Methods used to treat SILs include cold cautery (freezing that destroys tissue), laser treatment (surgery with a high-intensity light), LEEP (loop electrosurgical excision procedure, the removal of tissue using a hot wire loop), as well as conventional surgery. Similar treatments may be used for external genital warts. In addition, two powerful chemicals (podophyllin and trichloroacetic acid) are capable of destroying external genital warts when applied directly to them. Imiquimod cream has also been recently approved by the Food and Drug Administration (FDA) as an effective drug treatment. Imiquimod works by stimulating the immune system to fight the virus.

REFERENCES:

Scully C. Oral squamous cell carcinoma; from an hypothesis about a virus, to concern about possible sexual transmission.

Oral Oncol. 2002 Apr;38(3):227-34. Review.

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