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Flashcards in Neoplasia 2 Deck (33)
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1
Q

What are the two categories of carcinogenic chemicals/agents?

A
  1. Direct acting

2. Indirect acting

2
Q

Name two examples of direct acting agents.

A
  1. Alkylating agents

2. Acylating agents

3
Q

What characterizes an indirect acting carcinogen? What is the consequence of this?

A

They require metabolic conversion to an ultimate carcinogen. Consequently, polymorphisms of enzymes like P450 can influence carcinogenesis.

4
Q

What are the two steps of clinical carcinogenesis?

A

Initiation and promotion.

5
Q

Is the damage incurred after initiation by a carcinogen reversible?

A

Nope

6
Q

Can carcinogenesis occur if exposure to a promoting carcinogen happens before exposure to an initiating carcinogen?

A

Nope

7
Q

Are the effects of chemical promoters reversible? Do they act directly on DNA? What do they do?

A

Yeah. They do not act directly on DNA. They promote cell proliferation.

8
Q

All initiating carcinogens are reacting _________ that react with ________ sites in the cell.

A

electrophiles that react with nucleophilic cellular sites

9
Q

Which particular UV ray type is most dangerous?

A

UV-B

10
Q

What causes melanomas? What causes determines risk for non-melanomas?

A

Melanomas are caused by intense intermittent exposure. Non-melanomas are a result of total cumulative exposure to UV radiation.

11
Q

What does UV radiation do to DNA?

A

Forms pyrimidine dimers (between adjacent cytosine nucleotides)

12
Q

By which two mechanisms can ionizing radiation cause mutations?

A

Directly on DNA or indirectly by hitting water or oxygen in the cell, generating free radicals, that can then damage DNA

13
Q

Name three oncogenic DNA viruses.

A
  1. HPV
  2. EBV
  3. Hep B
14
Q

Name an oncogenic RNA virus.

A

Human T cell lymphotrophic virus

15
Q

Name an oncogenic bacteria. What does it cause?

A

H. pylori causes gastric adenocarcinoma and MALT lymphoma

16
Q

Which HPV types are considered high risk for cervical cancer and what genes in particular must integrate into the host chromosome?

A

Types 16 and 18 are high risk. E6 and E7 genes must integrate. E6 degrades p53 and E7 sequesters Rb.

17
Q

What is the only human retrovirus implicated in carcinogenesis?

A

Human T cell lymphotrophic virus type 1.

18
Q

What type of cancer does Human T cell lymphotrophic virus cause? In what parts of the world is it most common?

A

T cell leukemia-lymphoma. Most common in Japan and the Carribean basin.

19
Q

What is the mechanism of carcinogenesis of Human T cell lymphotrophic virus?

A

It encodes a viral transcription activation protein called TAX which turns on genes for cytokines and their receptors in T cells, causing an autocrine and paracrine signaling loop that results in cell proliferation. Further mutations can result in monoclonal T cell development.

20
Q

What is the first bacteria classified as a carcinogen? What is the pathogenesis to gastric cancer?

A

Heliobacter pylori. Chronic inflammation/gastritis –> gastric atrophy –> metaplasia –> dysplasia –> cancer

21
Q

What is the cellular origin of gastric lymphomas? Hint: they are found in MALT

A

B-cells

22
Q

What is the pathogenesis of MALT marginal zone associated B cell lymphoma?

A

T cells expand to fight H. pylori, causing polyclonal B cell proliferation –> B cell mutations –> monoclonal B cell tumor

23
Q

What chemicals are thought to play a large role in cancer cachexia?

A

Cytokines produced by the tumor and host in response to the tumor such as TNF from macrophages.

24
Q

What is a paraneoplastic syndrome? How common is it?

A

When tumors randomly synthesize compounds/hormones unexpectedly. Found in 10-15% of cancer patients.

25
Q

Name two endocrinopathies with ectopic hormone production and explain what they are.

A
  1. Cushing syndrome - small cell lung carcinoma, pancreatic carcinoma, or neural tumor that secretes ACTH or an ACTH-like chemical.
  2. Hypercalcemia caused by PTH-like secretions from squamous cell carcinoma of the lung, breast carcinoma, renal carcinoma, ovarian carcinoma, or T cell leukemia/lymphoma.
26
Q

How can cancer cause thombotic endocarditis? What is thrombotic endocarditis?

A

It is when blood clots mess up heart valves. Mechanism unknown but some advanced cancers can cause hypercoagulability and cause the endocarditis.

27
Q

Grading reflects ________ _________, whereas staging reflects ________ ____ _______.

A

grading reflects cellular characteristics whereas staging reflects the extent of spread

28
Q

Describe the system of staging.

A
T = site and extent of primary tumor
N = regional lymph node involvement
M = distant metastasis
29
Q

What four methods can be employed to diagnose cancer?

A
  1. Histopathology
  2. Flow cytometry
  3. Molecular diagnostics
  4. Tumor markers
30
Q

Which HPV types cause benign squamous papillomas? Which ones have a low malignant potential?

A

Benign squamous papillomas: 1, 2, 4, 7

Low malignant potential: 6 and 11

31
Q

Does Human T cell lymphotropic virus carry an oncogene?

A

No, the TAX protein is a viral protein and is not considered an oncogene because it doesn’t integrate into the host genome to produce malignancy.

32
Q

Which infectious carcinogenic organism infects 50% of the world population while only 3% have cancer as a result?

A

H. pylori

33
Q

PSA testing is an example of which cancer diagnosis method?

A

Tumor markers