Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Foundations of Disease and Therapy > Viruses and Cancer > Flashcards

Viruses and Cancer Flashcards

1
Q

Development of Adult T Cell Leukemia

A

HTLV-1 encodes Tax, which is an growth-promoting gene that causes replication and proliferation of the host cell

As T Cells proliferate, immune cells begin to recognize Tax

Normally, this is enough to prevent cancer, but can lead to cancer in immunocompromised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

B Cell Lymphoma Immunotherapy

A

Rituximab as a monoclonal antibody that targets CD 20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Progression of EBV and KSHV to Cancer

A

Disease is caused by unregulated proliferation of infected cells and is associated with immunosuppression

Diseases are associated with latency - viral genes are transcribed during this period (compared to HSV where no genes are transcribed)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Burkitt’s Lymphoma

A

Unexplained swollen painless lymph nodes, may have expanding abdominal mass

Endemic to Africa

Malaria is a cofactor for development of Burkitt Lymphoma

Involves dysregulated form of c-MYC from t(8,14) translocation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Diagnosis and Treatment of Merkel Cell Carcinoma

A

Tumor cells express Cytokeratin 20 and MCV Large T

Treat with surgical excision, lymph node surgery, ratiation, and chemotherapy

Treat the Tumor, not the virus!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Merkel Cell Virus

A

Polyoma Virus that encodes Large T oncoprotein

Causes Merkel Cell Carcinoma, a rare neuroendocrine carcinoma of the skin that affects mostly older white men

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Tropism of EBV and KSHV

A

EBV: B cells and epithelial cells

KSHV: endothelial, epithelial, and B cells (much less prevalent in population than EBV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pap Smear

A

Includes Nuclear stain, Orange keratin stain, and light green stain for Cytoplasm of other cells

A normal pap smear should show no keratin, and cells should have a small, dense nucleus

Abnormal pap smear shows keritinization, dyskaryosis, microvascularization, and perinuclear clearing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Low risk HPV

A

The E6 and E7 proteins of low-risk HPV do not suppress activity of p53 and Rb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does HPV lead to cancer?

A

E6 and E7 are only expressed when virus integrates into genome

This is because the Circular DNA of HPV breaks at the center of the L1 gene and E2 gene

E2 protein blocks transcription of E6 and E7

Lack of L1 helps virus evade immunity

0.8% of infected people develop cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Characteristics of human tumor viruses

A
  1. High rates of infection, low rates of cancer
  2. Cancer occurs many years after infection
  3. Virus causes initiation events and allows cells to outlive their lifespan or removes cell cycle breaks
  4. Viral genomes become integrated into host cell genome
  5. Often activate signaling proteins or express oncogenes
  6. Patient’s immune response plays a role - chronic immune response in regerative tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

EBV and Lymphomas

A

Burkitt’s Lymphoma - Common in African Children, t(8,14)

CNS Lymphomas - 100% caused by EBV, associated with AIDS

Hodgkin’s Disease - Hispanic, men, HIV+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Important proteins in HPV

A

L1 Protein - encodes the capsid - target for vaccine and new PCR diagnostics

E6 - inactivates p53

E7 - inactivates Rb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where does HPV preferentially infect?

A

Narrow transformation zone at transition between columnar epithelium and squamous epithelium

This transition occurs in cervix and rectum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

HPV Vaccine

(strains, approved for, protection percent)

A

Protects against HPV 6, 11, 16, and 18

Vaccine is against L1 Proteins

Approved for women and men age 9-26

Protects against 90% of genital warts and 70% of cervical cancer

Newer vaccine protects against 9 strains and covers 90% of cervical cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pros and Cons of PCR test for HPV

A

Pros: Cheaper and easier

Cons: Doesn’t detect non-HPV Cervical Cancer (about 10%), doesn’t identify later stage of virus after it integrates (no more L1 protein)

17
Q

Primary Effusion Lymphoma

A

Usually occurs in people who are both EBV and KHSV positive

Lymphoma of pleural cavity

Highly resistant to therapy

Treat with chemotherapy - not HAART

18
Q

HPV and Oral Cancer

A
  • Commonly affects males
  • HPV-related oropharyngeal cancers have better prognosis than other forms because it’s more responsive to treatment
  • Most commonly caused by HPV 16
19
Q

Diseases of EBV

A
  1. Oral Hairy Leukoplakia
  2. Nasopharyngeal Carcinoma
  3. EBV Mononucleosis (characterized by heterophile antibodies)
  4. Bukitt’s lumphoma
  5. Hodgkin’s Lymphoma
20
Q

Why does HIV lead to cancer if it just affects CD 4 cells?

A

CD 4 cells have a required co-signal to efficiently activate CD 8 cells

If CD 8 cells are not efficiently activated, they cannot stop cancer

This is why you can treat many cancers by fixing the underlying immunocompromised state

21
Q

Inflammation and Cancer

A

Hepatitis B and Hepatitis C cause chronic inflammation in liver cells, which generates reactive oxygen species and constant regeneration

Eventually this may lead to mutations that accumulate and cause cancer

22
Q

How EBV transforms B Cells

A

Normal B cells require T Cell co-signal in order to proliferate; and they commit apotposis when they stop receiving this signal (CD 40 on B Cell binds CD 40L on T Cell)

EBV Latency proteins induce antigen-independent B Cell proliferation and differentiation without the need for co-stimulatory signal

This results in large proliferation of B Cells, which can lead to cancer. Normally this proliferation is controlled by killer T cells, but can be dysregulated in immunocompromised

23
Q

Why don’t viruses that actively replicate cause cancer?

A

Active viral replication causes cell lysis, which prevents the cell from becoming cancerous

24
Q

Oral Hairy Leukoplakia

A

White plaque on tongue that cannot be scraped off

Caused by EBV in immunocompromised

25
Q

Treatment for Lymphomas

A

Treating the HIV can treat the cancer

Use HAART to restore immune response

26
Q

Name some ways viruses can cause a cell to progress towards cancer

A
  1. Damage to DNA
  2. Impaired Apoptosis (p53)
  3. Inactivation of tumor suppressor genes (Rb)
  4. Activation of growth-promoting oncogenes
  5. Altered gene products (proteins); abnormal structural and regulatory proteins
27
Q

Viral proteins that attack Rb

A

E7 (papilloma viruses) and Large T (polyoma viruses)

28
Q

EBV Nasopharyngeal Carcinoma

A

Rare in US; Common in China/Taiwan

Difficult to diagnose

29
Q

Ways to screen for cancer caused by HPV

A
  1. Pap Smear
  2. PCR for L1 protein
30
Q

HTLV-1

(disease, infectivity)

A

Causes Adult T Cell Leukemia in 1-4% of people it infects; cancer occurs 20-30 years after infection

HTLV-1 genome is integrated with host genome

31
Q

Enzymes that activate antiviral drugs in Alpha Herpes Virus vs Beta Herpes Viruses and CMV

A

Alpha: Thymidine Kinase

Beta and CMV: Phosphotransferase

32
Q

Risk factors for Merkel Cell Carcinoma

A

UV A exposure

Weakened immune system (HIV, organ transplant)

White males over 50

33
Q

proteins that attack p53

A

E6 (papilloma viruses) and Large T (polyoma viruses)

34
Q

Differences between Papilloma and Polyoma Viruses

A

The differences are the oncogenic proteins;

Papilloma Viruses contain E6 and E7

Polyoma Viruses contain Large T

35
Q

Why it’s important for viruses to inactivate p53

A

Viral DNA looks like damaged DNA to the cell, so inactivating p53 helps prevents Apoptosis and/or removal of viral DNA

36
Q

KSHV (HHV-8)

A

Kaposi’s Sarcoma - AIDS defining malignancy

Multicentric neoplasm consisting of multiple vascular nodules in skin

Treated with HAART

37
Q

Know the types of Papilloma Virus and what diseases they cause

A

Types 1 and 2 - Common warts

Types 6 and 11 - Genital warts

Types 16 and 18 - Cervical Cancer

38
Q

PD-1

A

Protein found on Killer T cells that makes their activation less likely

Many tumors express a PD-1 ligand to prevent Cytotoxic Cell Destruction

New Monoclonal Antibodies (Avelumab and Pembrolizumab) target this receptor to allow T Cells to kill cancer

39
Q

Percent of human cancers related to viruses

A

up to 35%

Foundations of Disease and Therapy (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions