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

What percent of cancers are associated with infection?

20%
12-15% are viral

2

Structure of HPV

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

3

What are the oncogenes in HPV?

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

4

HPV lifecycle

Only infects undifferentiated proliferating basal layer cells

Produced only from fully differentiated upper layer cells

5

Epidemiology of HPV

70-85% lifetime risk

Even bigger prevalence in developing countries

6

Risk factors of HPV infection

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

7

What are the high-risk HPV types?

HPV16, HPV18, 31, 33, 45

8

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

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

9

Cytology of cervical cancer

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

10

How does HPV cause cancer

High-risk HPV is frequently integrated into host chromosome
Inhibits tumor suppressors p53 and Rb (E2F also)

11

How does HPV testing work?

DNA detection (PCR)
mRNA detection

12

Colposcopy

Used if pap smear is abnormal
To get a better look and take biopsies of abnormal areas

13

Treatment for patients at high risk of cervical cancer

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

14

HPV vaccines

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

15

How to make HPV vaccine

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

Limitations of HPV vaccines

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