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GUIDE > HUMAN PAPILLOMA VIRUS |
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MOUTH CANCER 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 types
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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