8.2 Viral infections & cancers Flashcards
cell cycle machinery controls what ?
cell proliferation
Cancer is a disease of ?
inappropriate cell proliferation
What’s oncogene ?
genetic material that carries the ability to induce cancer
A checkpoint is a ….. mechanism in the cell cycle
regulatory
What is p53 ?
human suppressor gene
What are 2 checkpoints in cell cycle ?
- G1/S checkpoint
- G2/M checkpoint
p53 exerts its effects mainly through what protein ?
p21
what does p21 inhibit ? which does what ?
cyclin-dependent kinases (CDKs), prevent the progressing to next phase
what does p53 arrest ?
cell cycle for DNA repair if damage is detected
When p53 arrests cell cycle for DNA repair if damage is detected what does it ensure ? [change ?!]
DNA repair before cell division induces DNA repair genes
If the DNA damage is irreparable , what does p53 do ?
promotes apoptosis by inducing the transcription of pro-apoptotic genes such as BAX and activation of caspases
What are oncogenic viruses ?
viruses that can cause cancer by altering the genetic material of host cells
Cancers caused by human papillomavirus (HPV) ?
- cervical
- anal
- oropharyngeal
- vulvar
- vaginal
- penile
Types of HPV ?
- high-risk HPV types include HPV-16 and HPV-18
cancers caused by epstein-barr virus ?
- Burkitt lymphoma
- Hodgkin lymphoma
- nasopharyngeal carcinoma
- gastric cancer
What is the primary mechanism by which epstein-barr virus (EBV) contributes to cancer development?
** latent infection of B cells and epithelial cells.**
[extra] During latency, the virus expresses specific genes that drive cell proliferation, prevent apoptosis, and evade immune detection.
cancers caused by heptitis B virus (HBV) ?
- hepatocellular carcinoma (liver cancer)
Mechanism of how hepatitis B virus leads to cancer ?
HBV can cause chronic liver infection, which may lead to liver cirrhosis, inflammation, and eventually hepatocellular carcinoma
cancers caused by hepatitis C virus (HCV )?
- hepatocellular carcinoma (liver cancer)
Mechanism of how hepatitis C virus leads to cancer ?
HCV can cause chronic liver infection, which may lead to liver cirrhosis, fibrosis, and eventually hepatocellular carcinoma
Cancers caused by human T-cell lymphotropic virus type 1 (HTLV-1) ?
adult T-cell leukemia/ lymphoma (ATLL)
mechanism of HTLV-1 (human T-cell lymphotropic virus type 1) to result in cancer ?
integration of viral DNA into host T-cell genome
cancers caused by Kaposi’s Sarcoma-associated Herpesvirus or Human Herpesvirus 8 (KSHV/HHV-8)
- Kaposi’s sarcoma
- primary effusion lymphoma
- multicentric Castleman disease.
mechanism of Kaposi’s Sarcoma-associated Herpesvirus or Human Herpesvirus 8 (KSHV/HHV-8) leading to causing cancer ?
latent infection in endothelial cells
cancers caused by merkel cell polyomavirus (MCV) ?
merkel cell carcinoma
mechanism for merkel cell polyomavirus (MCV) to cause cancer ?
integration of viral DNA leading to mutations
HPV is the most common….
sexually transmitted infection (STI)
Percentage of sexually active unvaccinated men and women that get the HPV virus at some point in their life ?
80%
Transmission of HPV ?
- more likely transmitted through direct contact
- with infected skin (i.e. wart is present)
testing for HPV ? males & females
- males - only visual exam
- females - visual exam & detection through smears
early proteins with HPV
E1- E7
what are HPV 6 and HPV 11 the cause of ? [remove]
- benign lesions of skin (warts)
- mucous membrane of the genital and anal areas
- extragenital (papillomas of the mouth )
- respiratory (recurrent respiratory papillomatosis)
What are HPV 16 and HPV 18 involved in the development of ?
- precancerous lesions
- cancers of various organs first and foremost the cervix
What are condylomata acuminata ?
benign anogenital warts most often caused by HPV types 6 and 11
What other types of warts other than condylomata acuminata can HPV types 6 and 11 cause?
laryngeal and oropharyngeal warts
How long is the incubation period for warts caused by HPV?
1 to 6 months
What are the characteristics of visible anogenital warts?
soft, moist, minute pink or gray polyps that can enlarge, become pedunculated, have rough surfaces, and may occur in clusters
What symptoms might patients with anogenital warts experience?
Although usually asymptomatic, some patients may experience itching, burning, or discomfort
Where do anogenital warts commonly occur in men?
commonly under the foreskin, on the coronal sulcus, within the urethral meatus, and on the penile shaft.
They may occur around the anus and in the rectum, especially in homosexual men
Where do anogenital warts commonly occur in women?
the vulva, vaginal wall, cervix, and perineum.
The urethra and anal region may also be affected.
Which HPV types usually cause flat endocervical or anal warts, and why are they difficult to diagnose?
HPV types 16 and 18
If condylomata acuminata (anogenital warts caused by HPV) gone untreated what happens ?
- 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
Cervical cancer develops from ..?
pre-cancerous stage of cervix known as cervical intraepithelial neoplasia (CIN)
change by persistence infection (dysplasia)
Cervical cancer appears to be cause by infection with what HPV types ? what’s the different between the types ?
- 16 , 18 = most common high risk , associated with pre-malignant regions
- 31, 33, 35, 39 =high risk
HPV type 16 most common which carcinoma ?
squamous cell