The Pathology of Cervical Dysplasia and Malignancy

Question 1

What are the histological gradings of precancerous cervical squamous lesions?

Answer 1

HPV, CIN1-3

Question 2

What are the cytological gradings of precancerous cervical squamous lesions?

Answer 2

low grade (encompassses HPV and CIN1) or high grade (encompasses CIN 2 and CIN 3)

Question 3

What type of virus is HPV?

Answer 3

a double stranded DNA virus

Question 4

Where does HPV infect?

Answer 4

squamous epithelium - at the mouth, genitals and skin (most commonly hands)

Question 5

How many different types of HPV are there?

Answer 5

130

Question 6

What is meant by high risk and low risk HPV?

Answer 6

their oncogenic potential

Question 7

Where is there the highest incidence of HPV?

Answer 7

Africa, Asia and Latin America

Question 8

What percentage of cervical cancers are attributable to HPV?

Answer 8

100%

Question 9

Which HPV types account for the majority of cervical cancers?

Answer 9

HPV-16 and HPV-18

Question 10

Which age group has the highest prevalence of HPV?

Answer 10

20-24

Question 11

What are the late genes of the HPV DNA responsible for?

Answer 11

the capsid

Question 12

What are the early genes of the HPV DNA responsible for?

Answer 12

replication, proliferation and viral release

Question 13

How does HPV infect?

Answer 13

there has to be pre-existing damage so that HPV can gain access to the basement membrane or basal keratinocytes - as capsid gains contact it can enter cells

Question 14

How does HPV propagate throughout cells?

Answer 14

with cell replication

Question 15

How does HPV reinfect?

Answer 15

as the keratinocytes are sloughed the HPV is released so its able to reinfect

Question 16

What is the structure of the DNA within the infected cells?

Answer 16

either episomal or integrated into the host DNA

Question 17

What is the role of the HPV E2 gene?

Answer 17

supresses transcription of HPV E6 and E7 genes

Question 18

What is the role of HPV E6 and E7 genes?

Answer 18

E6 binds to p53 (a tumour supressor gene) and deactivates it, E7 binds to Rb and deactivates it - the result of their expression is squamous cell carcinoma

Question 19

When are E6 and E7 expressed?

Answer 19

when the HPV integrates with the host DNA at a breakpoint in E2

Question 20

What is the difference between low risk and high risk HPV?

Answer 20

low risk is more likely to become latent and regress where as high risk is more likely to cause SCC

Question 21

What is the transformation zone?

Answer 21

the function between the ectocervix and endocervix - it is the site that is most susceptible to HPV

Question 22

What is a cervical condyloma?

Answer 22

a genital wart - there is no dysplasia but the squamous epithelium is thickened and there are koilocytes

Question 23

What are koilocytes?

Answer 23

squamous epithelial cells with nuclear enlargement, irregularity of the nuclear membrane, hyperchromasia and nuclear halo

Question 24

What is a flat condyloma?

Answer 24

a flat cervical lesion - contains koilocytes but isnt papillomatous

Question 25

What is CIN 1?

Answer 25

cervical intraepithelial neoplasia - mild dysplasia confined to the basal 1/3rd of the epithelium

Question 26

What is CIN 2?

Answer 26

dysplasia confined to the basal 2/3rds of the epithelium

Question 27

What is CIN 3?

Answer 27

severe dysplasia in greater than 2/3rds of the epithelium

Question 28

When is the lesion regarded as squamous cell carcinoma?

Answer 28

when it becomes infiltrative

Question 29

What other type of cancer can be caused by HPV in the cervix?

Answer 29

adenocarcinoma

Question 30

What is the recommended practise for a high grade intraepithelial lesion after a pap smear?

Answer 30

follow up with a colposcopy

Question 31

What is the target of the HPV vaccine?

Answer 31

the late proteins that encode for the capsid