Human Papillomaviruses and Associated Diseases Flashcards Preview

Infectious Disease Unit 1 > Human Papillomaviruses and Associated Diseases > Flashcards

Flashcards in Human Papillomaviruses and Associated Diseases Deck (16)
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1
Q

What percent of cancers are associated with infection?

A

20%

12-15% are viral

2
Q

Structure of HPV

A

Non-enveloped double stranded DNA virus
Capsid protein L1: 360 molecules (72 X 5)
Capsid protein L2: ~ 72 molecules

3
Q

What are the oncogenes in HPV?

A

E6, E7, E8: cell proliferation, transformation, immune escape

4
Q

HPV lifecycle

A

Only infects undifferentiated proliferating basal layer cells

Produced only from fully differentiated upper layer cells

5
Q

Epidemiology of HPV

A

70-85% lifetime risk

Even bigger prevalence in developing countries

6
Q

Risk factors of HPV infection

A
Early onset intercourse
Multiple Sex Partners
History of Genital Warts
Immunosuppressive disorders
No pap smears
Oral contraceptives
Smoking
7
Q

What are the high-risk HPV types?

A

HPV16, HPV18, 31, 33, 45

8
Q

What cancers can HPV cause and what percent of them is it responsible for?

A

Cervical cancer (100%)
Head and Neck cancer (25%)
Other anogenital cancers
Non-melanoma skin cancer?

9
Q

Cytology of cervical cancer

A

ASCUS: atypical squamous cell of undetermined significance
LSIL: Low-grade squamous intraepithelial lesion
HSIL: High-grade squamous intraepithelial lesion

10
Q

How does HPV cause cancer

A

High-risk HPV is frequently integrated into host chromosome

Inhibits tumor suppressors p53 and Rb (E2F also)

11
Q

How does HPV testing work?

A
DNA detection (PCR)
mRNA detection
12
Q

Colposcopy

A

Used if pap smear is abnormal

To get a better look and take biopsies of abnormal areas

13
Q

Treatment for patients at high risk of cervical cancer

A

Surgery (Cryosurgery, Loop electrosurgical excision procedure (LEEP))

14
Q

HPV vaccines

A

Three doses

For girls and boys 11-12 years old (before sexually active)

15
Q

How to make HPV vaccine

A

Inject HPV L1 capsid protein expressing gene into yeasts, , do mass culture, purify vaccine

By only having L1 protein, get empty virus that can make immune response without risk of infection (virus-like particle)

16
Q

Limitations of HPV vaccines

A
Lack therapeutic effect
Can only reduce incidence in future generations
Don't cover all HPV genotypes
High cost 
Opposition to vaccines by some groups