Lecture 8.2: Viral Infections and Cancers Flashcards
(37 cards)
What is an Oncogene?
Genetic material that carries the ability to induce cancer
What is Human Papillomavirus (HPV)?
• HPV is the most common sexually transmitted infection (STI)
How common is HPV?
80% of sexually active unvaccinated men and women get the virus at some point in their life
How to Test for HPV?
- Males –Only visual exam*
* Females –Visual exam and detection through smears
How is HPV Transmitted?
- More likely transmitted through direct contact
* With infected skin (i.e. wart is present)
What are Condylomata acuminata?
Benign anogenital warts most often caused by HPV types 6 and 11, as are laryngeal and oropharyngeal warts
What is the incubation period of warts?
1-6 months
Features of Visible Anogenital Warts (7)
- Soft
- Moist
- Minute pink or gray polyps
- Enlarge
- May become pedunculated
- Have rough surfaces
- May occur in clusters
Where do anogenital warts occur in men?
- Foreskin
- Coronal Sulcus
- Within the Urethral Meatus
- Penile Shaft
- Anus & Rectum
Where do anogenital warts occur in women?
- Vulva
- Vaginal Wall
- Cervix
- Perineum
- Urethra
- Anal Region
What types of HPV cause flat endocervical or anal warts that are difficult to see and diagnose clinically?
16 and 18
If untreated what can Condylomata acuminata lead to? (4)
- Transmission to sex partners and newborns
- Warts may grow and spread if left untreated
- May cause cervical cancer
- Block openings from anus, vagina and urethra
What HPV Types appear to cause Cervical Cancer?
HPV Type 16, 18, 31, 33, 35, or 39
What HPV Types most likely to cause cancer?
- HPV 16 and 18
- High Risk
Which HPV Types associated with benign warts?
- HPV 6 and 11
- Low Risk
Which cancer is HPV 16 most commonly linked to?
HPV16 is commonest in squamous cell carcinoma
Which cancer is HPV 18 most commonly linked to?
HPV18 is more associated with adenocarcinoma
Risk Factors for Cervical Cancer (6)
- Younger age at first intercourse
- A high lifetime number of sex partners
- Oral Contraceptives
- STIs
- Cigarette smoking
- Immunodeficiency
Symptoms of Cervical Cancer (8)
- Often Asymptomatic
- Irregular Vaginal Bleeding
- Pain during intercourse
- Foul-smelling Vaginal Discharge
- Pelvic Pain
- Obstructive Uropathy
- Back Pain
- Leg Swelling (due to venous or lymphatic obstruction)
- Pelvic examination may detect an exophytic necrotic tumor in the cervix
What is CIN (Cervical Intra-Epithelial Neoplasia)?
It is a term that describes abnormal changes of the cells that line the cervix
How is CIN (Cervical Intra-Epithelial Neoplasia) Graded?
1: Mild cervical dysplasia
2: Moderate dysplasia
3: Severe dysplasia and carcinoma in situ
CIN 1: Low Risk.
CIN 2 & 3: High Risk
Can CIN 3 Regress?
- CIN 3 is unlikely to regress spontaneously
- If untreated, over time it may penetrate the basement membrane
- Thus becoming invasive carcinoma
Mechanism of Action of HPV
1) Normal viral mode of infection
2) Viral DNA integrates with Host DNA
3) Alterations in genes can lead to carcinogenesis
What are the 3 different types of gene alterations HPV infection cause that may lead to carcinogenesis?
1) Loss of function of a tumour suppression gene
2) Enhanced expression of an oncogene
3) Interchromosomal rearrangements leading to altered gene expression in
involved regions
