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Foundations 2 > carcinogensis > Flashcards

carcinogensis Flashcards

1
Q

Bcl2 overexpression translocation

A

tr(14, 18), so translocates Bcl2 with Ig gene

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2
Q

What needs to happen for tumor to occur?

A

Initiator followed by promoter (regular sustained exposure)

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3
Q

Steps of carcinogenisis

A

tumor initiation (DNA damage or epigenetic changes) , tumor promotion (selective clonal expansion), malignant conversion, and tumor progression (metastasis potential)

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4
Q

What are chemical initiators like?

A

electrophilic (metabolite of drug Nzms), changes in DNA metabolism

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5
Q

Types of initiators?

A

direct: no transformation, alkylation and acylation
Indirect: metabolic conversion required

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6
Q

Features of initiators?

A

DNA adduct forms, DNA damage, and tissue specific

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7
Q

How is carcinogenic potential of initiators affected?

A

inherent reactivity, metabolite activation (CYP450) and inactivation (gluthathione-s-transferase) reactions, genetic polymorphisms

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8
Q

What do initiators do?

A

activate oncogene, alter apop pathway, inact of tumor suppressors, inact. DNA repair mech.

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9
Q

What do promoters do?

A

bind cell surface–cell proliferation, specific to tissue as interact with receptors

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10
Q

Types of general categories

A

specific promoters-interact with Receptors or in target cells defined tissues
Non-specific promoters: alter gene expression–w/o presence known receptors

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11
Q

Effects of promotors?

A

Maximal and threshold

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12
Q

mechanism of promoters

A

Epigenetic- change in gene exp. but no DNA damage; promoters induce cell prol. (mitogenic) (TPA-Phorbol esters)
less GF requirements and less responsive to inhibitors

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13
Q

Molecules for promoters mech

A

ROS, Redox metals, Polycylic aromaic compounds, (oxidative stress)

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14
Q

Eg. of Chemical carcinogen

A

Direct acting alkylating agents (guanine groups affected)–chemotherapy drugs

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15
Q

What do polycylcic hydrocarbons do?

A

initiators and promotors, metabolized by cyp450, electrophilic epoxides (cigeratte smoke have initiators and promotors, animal fat), eg. vinyl chloride

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16
Q

Chemical carcinogen: What do N-Nitrosamines do? Where is it?

A

CYP450, carbonium ion, indirect acting carcinogen; diet, tobacco smoke, drinking water (Nitrates are in water and vegetables), smoked meats, bear and whisky)

17
Q

Chemical carcinogen: What do aromatic amine and azo dyes do?

A

Naptheline, metabolite of cyp450, increased incidence of urothelial cancer and field effect

18
Q

What is field effect?

A

if exposed to entire epithelium, then cancer is likely to develop in the area (secondary tumor development)

19
Q

Chemical carcinogen: What does Aflatoxin B1 do?

A

from Aspergillus flavus (indirect carcinogen) epoxides bind to guanine in TP53–mutations; in improperly stored grain and peanuts (Hepatocellular cancer)

20
Q

What cancer does alcohol cause?

A

esophageal squamous, hepatocellular, Head and neck

21
Q

What cancer occurs due to arsenic exposure?

A

Lung squamous, skin, liver angiosarcoma; from cigeratte smoke

22
Q

What cancer occurs due to abestos exposure?

A

lung and mesothelioma (lung more though)

23
Q

What cancer occurs due to Ni, Chromium, Si, and Be exposure?

A

Lung and its occupational exposure

24
Q

What does UV radiation contribute to cancer?

A

UVB: DNA adducts, direct damage, pyrimidine dimers; and UVA: oxidation (indirect DNA damage), free radicals

25
Q

What is the result of UV radiation?

A

increase inflam, so ROS upregulates, inflam genes such as cox-2 increases PG prod.

26
Q

What is UVB induced inflammation associated with?

A

inact. or act of genes
inact. of p53;
act. of EGFR, COX2 (major role in squamous cell carcinoma) MAPKS, BCL2 (evade apop)

27
Q

What does ionizing radiation do?

A

x and gamma rays, risk for leukemia, carcinoma, breast, colon, thyroid, and lung
can be used for therapy but secondary cancers develop

28
Q

What cancer happens due to ionizing radiation?

A

AML, CML, Papillary ca. of thyroid; free radical generation

29
Q

What does HPV do?

A

inactivates Rb (By E7) and p53 (by E6)–ub protesome pathway–loss of tumor suppressor–risk of cancer

30
Q

What does EPV do?

A

Burkitt’s lymphoma-Chr translocation of tr(8,14), c-myc (chr 8) translocates to (14) with Ig –Bcell overexpresses c-myc
(Bcell lymphoma, T cell lymphoma and Hodgkin’s disease)

31
Q

How does HBV cause cancer?

A

liver cancer as Hbx binds to p53–inactivates; also liver injury–hyperplasia–> cancer

32
Q

hOW does HHV8 cause cancer?

A

Kaposi’s sarcoma–skin and gums (and certain B-cell lymphoma inusually HIV infected)
it forms neoplasm of lympathic endothelial cells

33
Q

How does HTLV-1 RNA oncovirus cause cancer?

A

tropic for CD4 T cel, activates IL-2 and IL-2R–polycolnal proliferation and 1% get leukemia

Foundations 2 (15 decks)

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