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(IARC) classified the genus beta HPV types 5 and 8 as “possible carcinogenic”
biological agents in EV disease.
3.6 HPV-Related Cancer Prevention
So far, HPV vaccines have been used mainly in the prevention of cervical cancer.
Prophylactic HPV vaccines were primarily designed and produced to prevent infec-
tion with the most common HR HPVs, types 16 and 18, which cause about 70% of
cervical cancer cases. The quadrivalent vaccine (4vHPV) Gardasil, marketed by
Merck, protects against initial infection with HPV types 6, 11, 16, and 18. Another
bivalent vaccine is Cervarix by GlaxoSmithKline that is protective against HPV16
and 18 [ 53 – 55 ]. Both vaccines are highly effective in preventing cervical dysplasia.
Countries that have achieved high coverage with the 4vHPV vaccine have seen
dramatic reductions in genital warts and infection with HPV16 and 18 [ 56 , 57 ]. The
Advisory Committee on Immunization Practices (ACIP) recommends routine HPV
vaccination starting at age 11 or 12 years, though the series can be started as early
as 9 years of age. Vaccination is also recommended for female ages 13 through
26 years and for males ages 13 through 21 years who have not completed the three-
dose series. Men up to age 26 should also be vaccinated if they have sex with men
or are immunocompromised [ 2 ].
The two HPV vaccines, i.e., Gardasil and Cervarix, approved for the use in cervi-cal cancer prevention by the FDA have been also been approved for other indica-
tions. Gardasil is now approved for the prevention of genital warts and the
HPV-associated precancerous lesions in the anogenital region besides prevention of
vulvar, vaginal, and anal cancers. Cervarix is approved for the prevention of precan-
cerous cervical lesions caused by HPV infection besides cervical cancer prevention.
These vaccines have not been approved as yet in the prevention of penile or oropha-
ryngeal cancer. The vaccine is however not effective if infections or lesions in the
cervix have already been reportedly caused by HPV [ 53 ].
A new 9-valent HPV vaccine (9vHPV) was approved by the FDA in December2014 for females ages 9–26 and males ages 9–15. In addition to the four HPV sub-
types (6, 11, 16, 18) found in the quadrivalent vaccine, it includes five additional
oncogenic HPV subtypes (31, 33, 45, 52, 58), which cause an additional 15% of
cervical cancer. In March 2015, the ACIP updated their guidelines to allow substitu-
tion of the 9vHPV vaccine for the quadrivalent vaccine [ 58 ].
Cervical screening should be sought by women, even if she has received the vac-cine. Furthermore, the recommendations for screening continue to remain the same
even for females who have received the HPV vaccine. Other preventive and cost-
effective strategies continue to play an important role, especially in the context of
developing countries [ 59 ].
Great progress has also been made to develop and improve therapeutic HPV vac-cines to treat existing HPV infections and diseases. These are being targeted to E6
and E7 oncoproteins that are expressed throughout the life cycle of thevirus [ 60 , 61 ].
Y. Li and C. Xu