Case 28: HPV Flashcards
what is the clinical presentation of HPV in a female?
- small, raised lesions on the cervix
- labial venereal warts
- friable, erythematous cervix
blood labs should be fine
what diagnostic workup should you do if you suspect HPV?
- Pap smear is necessary but it’s not sufficient since there’s 50% false negative
- DNA hybridization of biopsy for HPV
- ELISA assay to detect HPV-specific IgG antibody
what are the characteristics of the HPV virion?
- naked viruses of icosahedral symmetry
- double-stranded circular DNA
do HPV viruses grow in cell cultures?
nope
so you have to test them using molecularly cloned HPV DNA of a known type as a standard
which HPV strains cause common warts on nongenital tissue?
1,2,4,26,27,29
which HPV strains cause plantar warts on nongenital skin?
1,2,4,63
which HPV strains cause epidermodysplasia verruciformis?
3,10, 27, 38
which HPV strains cause skin cancers in transplan recipients?
48, 60
which HPV strains cause anogenital warts?
6 and 11
which HPV strains cause dysplasias and cancer?
16, 18, 31, 33 and 35
how is HPV spread?
the types of HPV that infect the genital
area are spread primarily through genital contact
do HPV infections have symptoms?
not really
most HPV infections have no
signs or symptoms; therefore, most infected persons are unaware they are infected
they can still transmit the virus to a sex partner
what are the risk factors for HPV infection leading to
carcinoma of the cervix?
- sex before 15
- multiple partners
- exposure to other STDs
- mother/sister with cervical cancer
- smoking
- immunosuppression
- HIV/AIDS
- chronic corticosteroid use
what is the pathology of HPV?
HPVs infect the squamous epithelial cells of the basal layer of the skin or mucous
membrane
they enter basal cells that have been exposed through a disturbed epithelial
barrier, as would occur during sexual intercourse
where does HPV replicate?
nucleus
consequently, They enter basal cells that have been exposed through a disturbed epithelial
barrier, as would occur during sexual intercourse. like perinuclear clearing (halo) or a shrunken nucleus
sometimes in low-risk HPV strains, the HPV genome exists as a circular, episomal DNA separate from
the host cell nucleus – the infection is characterized by proliferation and thickening of
the basal layer, leading to the appearance of a wart
how do you treat HPV?
the goal is to remove symptomatic warts
whether or not removing the warts actuall decreases transmission is unknown
also no evidence indicates that the presence of genital warts or their treatment is associated with the development of cervical cancer
which HPV strains cause cervical cancer?
16 & 18
these cause carcinoma of the cervix!
HPV strains that cause genital warts aren’t the same as the HPV strains that cause cancer
how do HPV 16 & 18 cause cervical cancer?
HPV types 16 and 18 typically are integrated into the host cell DNA
integration of
the viral genome into the host cell genome is considered a hallmark of malignant transformation
HPV proteins E6 and
E7 of HPV types 16 and 18 inactivate the host’s tumor suppressor proteins p53 and retinoblastoma (Rb) and subvert the
cell growth regulatory pathways
they modify the cellular environment in order to facilitate viral replication in a cell
that is terminally differentiated and has exited the cell cycle
the result is an unregulated epithelial growth, which
begins at the basal layer and extends outward (dysplasia) and may progress to invasive squamous cell carcinoma
how do you prevent HPV?
condoms
regular Pap smears to screen for cervical cancer
