Chapter 6 - Carcinogenesis / Mutagenesis Flashcards Preview

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Flashcards in Chapter 6 - Carcinogenesis / Mutagenesis Deck (76):
0

All of the following are true of nongenotoxic carcinogens except...

A. There is a threshold

B. They are mutagenic

C. They cause no direct DNA damage

D. They can be tissue specific

B. They are mutagenic

1

Which of the following benin-malignant neoplasm pairs is incorrect?

A. Lipoma-liposarcoma
B. Hemangioma-angiosarcoma
C. Squamous cell papilloma-squamous cell sarcoma
D. Bronchial adenoma-bronchogenic carcinoma

C. Squamous cell papilloma-squamous cell sarcoma

2

All of the following are possible outcomes for initiated cells in the neoplastic process except...

A. Cell death via apoptosis

B. immediate distant metastatic spread

C. Can remain in static, nondividing state

D. Can undergo cell division to increase population of initiated cells

B. immediate distant metastatic spread

3

The progression state of carcinogenesis...

A. Is reversible

B. Involves conversion from preneoplasm to neoplasm

C. Does not involve DNA modification

D. Always forms a carcinoma

B. Involves conversion from preneoplasm to neoplasm

4

All of the following are true of the promotion stage of carcinogenesis except...

A. Multiple cell divisions are necessary

B. Only a single treatment is needed

C. DNA is not directly modified

D. Decrease in apoptosis may be a mechanism

B. Only a single treatment is needed

5

The carcinogenicity of inorganic arsenic is unusual in that...

A. It causes cancer in humans, but probably not animals

B. It causes different cancers in humans and animals

C. It causes cancer in animals but not humans

D. It causes cancer in plants, but not animals

A. It causes cancer in humans, but probably not animals

6

The most prevalent DNA adduct is...

A. 5-hydroxyuracil

B. thymine glycol

C. 8-hydroxyguanine

D. 9-oxoguanine

C. 8-hydroxyguanine

7

Malignant neoplasms of epithelial origin are called...

A. Sarcomas

B. Fibromas

C. Carcinomas

D. Papilloma

C. Carcinomas

8

Malignant neoplasms of mesenchymal origins are called...

A. Sarcomas

B. Fibromas

C. Carcinomas

D. Papilloma

C. Carcinomas

9

A carcinogen is an agent that when administered to animals...

A. Increases the incidence of malignant neoplasms

B. increases the incidence of benign neoplasms

C. Increases the incidence of background neoplasms

D. All of the above

D. All of the above

10

An IARC carcinogenic classification of 2A means...

A. The chemical is probably carcinogenic in humans

B. Animal data is positive for cancer development

C. Human epidemiology data is suggestive of cancer causation

D. All of the above

D. All of the above

11

Which of the following occupational carcinogen-cancer type pairs is incorrect?

A. Formaldehyde-astrocytoma

B. arsenic-skin cancer

C. Nickel-nasal sinus cancer

D. Benzidine-bladder carcinoma

A. Formaldehyde-astrocytoma

12

The development of tumors in rodents after the implantation of solid material is known as...

A. Multiple-hit carcinogenesis

B. Solid-state carcinogenesis

C. Single-hit carcinogenesis

D. Non-mutational carcinogenesis

B. Solid-state carcinogenesis

13

Alpha 2u globulin nephropathy from hydrocarbons and gastric neuroendocrine cell neoplasia from omeprazole are examples of neoplastic effects in rodents with...

A. No significance in humans

B. Some evidence for human cancer asso

C. Strong evidence for human cancer asso

D. IARC 2B classification in human

A. No significance in humans

14

Cosmetic preparations applied to the skin of the SKH1 albino hairless mouse would likely involve a test for...

A. Tumor progression

B. solid-state carcinogenesis

C. Photochemical carcinogenesis

D. Anticarcinogenesis

C. Photochemical carcinogenesis

15

The Syrian hamster embryo (SHE) assay is an example of a/an...

A. In vivo assay

B. 2-year bioassay

C. Organ specific assay

D. Transformation assay

D. Transformation assay

16

In a classic experimental demonstration of cancer development in mouse skin, croton oil was used as...

A. An initiator

B. a promoter

C. A vehicle

D. A placebo

B. a promoter

17

All of the following are true of the chronic (2-year) carcinogenicity bioassay except...

A. FDA mandates use of dogs and monkeys

B. A vehicle control and 2 or 3 doses of test chemical

C. Male and female animals are used

D. At necropsy, the number, location and pathology of each tumor are assessed

A. FDA mandates use of dogs and monkeys

18

Which of the following lifestyle-cancer associations is incorrect?

A. Dietary fat-melanoma

B. tobacco smoking-bladder cancer

C. Ethanol-oral cancer

D. Moldy food-liver cancer

A. Dietary fat-melanoma

19

Which of the following drug-cancer associations is incorrect?

A. Thorotrast-angiosarcoma of the liver

B. phenacetin-carcinoma of the renal pelvis

C. Diethylstilbestrol-clear cell vaginal carcinoma

D. Estrogens-prostate cancer

D. Estrogens-prostate cancer

20

Which of the following tumor suppressor gene-neoplasm pairs is incorrect?

A. P16-melanoma

B. Rb1-small cell lung carcinoma

C. BRCA1-osteosarcoma

D. WT1-lung cancer

C. BRCA1-osteosarcoma

21

All of the following are true of the p53 gene except...

A. it is essential for checkpoint control during cell division

B. the active form is a hexamer of 6 identical subunits

C. Enhanced MDM2 in tumor cells decreases functional p53

D. Mutations are asso w/ lung, colon and breast cancer

B. the active form is a hexamer of 6 identical subunits

22

All of the following are true of carcinogens that initially at lower doses demonstrate protection against carcinogenesis except...

A. Induction of P450 enzymes as a possible mechanism

B. Exhibit a J-shaped dose-response curve

C. Simulation of adaptive responses that dominate at low doses

D. A mechanism that is only exhibited by tumor promoters

D. A mechanism that is only exhibited by tumor promoters

23

Which pair of the following chemoprotective agent-mechanism pair is incorrect?

A. Vitamin D - inhibition of cytochrome P450

B. Vitamin C - antioxidant

C. Vanillin - increase in DNA repair

D. Folic acid - correct DNA methylation imbalances

A. Vitamin D - inhibition of cytochrome P450

24

Big Blue and Muta Mouse are examples of...

A. In vitro gene mutation assays

B. Assays that test for tumor promoters and not initiators

C. Transgenic models

D. None of the above

C. Transgenic models

25

All of the following statements are true regarding gap-junctional intracellular communication except...

A. Small molecules less than 1 kDa can be exchanged through neighboring cells

B. It is inhibited by tumor promoters

C. Carcinogens that interfere with it are not tissue and species specific

D. It is achieved by connexin hexamers that form a pore between adjacent cells

C. Carcinogens that interfere with it are not tissue and species specific

26

All of the following are true statements regarding GSTM1 except...

A. It demonstrates high reactivity toward epoxides

B. humans possessing the null isoform have a higher risk for bladder and gastric cancer

C. It is primarily a detox enzyme

D. The null isoform is protective in breast cancer

D. The null isoform is protective in breast cancer

27

All of the following are true regarding proto-oncogenes except...

A. There are no known oncogenic virus analogues

B. They are dominant

C. Somatic mutations can be activated during all stages of carcinogenesis

D. Germ line inheritance of these genes is rarely involved in cancer development

A. There are no known oncogenic virus analogues

28

All of the following are true regarding oncogenes except...

A. No known oncogenic virus analogue

B. They are recessive

C. Broad tissue specificity for cancer development

D. Somatic mutations activated during all stages of carcinogenesis

B. They are recessive

29

All of the following are true regarding tumor suppressor genes except...

A. BRCA1 is an example

B. they are recessive

C. No oncogenic virus analogues

D. Germ line inheritance is never involved in cancer development

D. Germ line inheritance is never involved in cancer development

30

Which of the following species develops cancer after exposure to a PPAR agonist?

A. Monkey

B. pig

C. Mouse

D. Guinea pig

C. Mouse

31

All of the following are PPAR agonists except...

A. 3-methylcholanthrene

B. clofibrate

C. Trichloroethylene

D. Diethylhexyl phthalate

A. 3-methylcholanthrene

32

What do PPAR alpha agonists, phenobarbital and TCCD have in common?

A. They all cause human cancer

B. They all bind to response elements that modulate gene tx

C. They all bind to nuclear receptors that induce cytochrome 2D6

D. They are all genotoxic in at least one species

B. They all bind to response elements that modulate gene tx

33

All of the following are agonists at the estrogen receptor except...

A. DES

B. bisphenol A

C. Nonylphenol

D. Tamoxifen

D. Tamoxifen

34

Chemicals that increase reactive oxygen species can affect expression of genes regulating...

A. Proliferation

B. Differentiation

C. Apoptosis

D. All of the above

D. All of the above

35

Melamine causes nongenotoxic carcinogenicity by the mechanism of...

A. Altered DNA methylation

B. induction of oxidative stress

C. Cytotoxicity

D. Stimulation of PPAR alpha receptors

C. Cytotoxicity

36

All of the following are true of aromatic amines except...

A. They are ultimate carcinogens

B. Aniline dyes are examples

C. They are associated with bladder cancer

D. They form reactive metabolites after phase I biotransformation

A. They are ultimate carcinogens

37

The carcinogenicity of nongenotoxic chemicals that cause cytotoxicity is due to...

A. Hormonal factors

B. Increase in spontaneous mutations from secondary hyperplasia

C. Acidosis

D. Acute phase reactants

B. Increase in spontaneous mutations from secondary hyperplasia

38

All of the following produce renal tumors in male rats except...

A. Inorganic arsenic

B. D-limonene

C. 1,4 dichlorobenzine

D. Trimethylpentane

A. Inorganic arsenic

39

PPAR agonists produce all of the following tumor types in rats except...

A. Hepatocellular carcinoma

B. pancreatic acinar cell tumors

C. Leydig cell tumors

D. Glioblastoma

D. Glioblastoma

40

Which of the following statements is true?

A. Ethylating carcinogenic agents produce adducts mostly in the phosphate backbone of DNA.

B. Oxidative DNA adducts occur only on adenine

C. The presence of a DNA adduct is sufficient for carcinogenesis

D. There is no repair for oxidative damage

A. Ethylating carcinogenic agents produce adducts mostly in the phosphate backbone of DNA.

41

All of the following are true statements except?

A. The predominant adduct formed from methylating agents is 7-methyl guanine

B. unpaired electrons on S, O, and N are nucleophillic targets of electrophiles

C. Hypomethylated genes are rarely transcribed

D. Chemical carcinogens react with proteins

C. Hypomethylated genes are rarely transcribed

42

Which of the following carcinogen-DNA damage pairs is incorrect?

A. Mustards-DNA crosslinks

B. UV light - pyrimidine dimers

C. Nongenotoxic carcinogens - 7-alkylguanine

D. Ionizing radiation - double stranded breaks

C. Nongenotoxic carcinogens - 7-alkylguanine

43

Which of the following statements is incorrect?

A. Mutations in an oncogene can result in a clonal cell population with a survival advantage

B. DNA damage leads to cell death or neoplasms, never to synthesis of abnormal proteins

C. Human cancer is usually the result of chronic exposure to a carcinogen

D. DNA polymerases can correct miscopied DNA bases during replication

B. DNA damage leads to cell death or neoplasms, never to synthesis of abnormal proteins

44

All of the following are examples of DNA repair except...

A. Reverse transcriptive repair

B. mismatch repair

C. Excision repair

D. End-joing repair of nonhomologous DNA

A. Reverse transcriptive repair

45

All of the following are reactive carcinogenic electrophiles except...

A. Strained lactones

B. carbonium ions

C. Selenium ions

D. Epoxides

C. Selenium ions

46

Direct-acting carcinogens include all of the following except...

A. Mustard gas

B. Imines

C. Sulfate esters

D. Aromatic rings

D. Aromatic rings

47

Which of the following is an ultimate carcinogen?

A. Safrole

B. Aflatoxin B1

C. Benzidine

D. Benzo(a)pyrine 7,8-diol 9,10 epoxide

D. Benzo(a)pyrine 7,8-diol 9,10 epoxide

48

Which of the following are true of the dominant lethal assay except...

A. Males are the treated sex

B. Both germ cell and somatic cell mutations are measured

C. Embryonic death is the endpoint

D. The mouse or rat are usually used

B. Both germ cell and somatic cell mutations are measured

49

The first indication that a chemical is a mutagen is often its...

A. pKa

B. chemical structure

C. Octanol-water coefficient

D. Dielectric constant

B. chemical structure

50

Smokers are likely to have...

A. Increased numbers of SCE

B. Increased frequency of chromosomal abberations

C. Increased number of DNA adducts

D. All of the above

D. All of the above

51

The detection of chromosomal aberrations has been made easier by the development of...

A. FISH

B. HERS

C. BASH

D. NORM

A. FISH

52

Mutation by chemicals usually causes all of the following except...

A. DNA adducts

B. Base substitutions

C. Double-stranded DNA breaks

D. Errors of DNA replication

C. Double-stranded DNA breaks

53

Aneuploidy can be defined as...

A. The gain of one or more chromosomes

B. The loss of one or more chromosomes

C. Both A and B

D. Neither A or B

C. Both A and B

54

All of the following statements are true except...

A. About 0.01% of newborns are afflicted with genetic diseases

B. about 5% of all recognized pregnancies contain chromosomal abnormalities

C. The frequency of aneuploidy in human sperm is 3-4%

D. About 30% of all spontaneous abortions and fetal deaths are associated with chromosomal abnormalities

A. About 0.01% of newborns are afflicted with genetic diseases

55

All of the following are true regarding endogenous DNA damage except...

A. DNA replication is error prone and contributes to incorrect base sequences

B. Endogenous agents are responsible for 3 errors per 100 cells per day

C. Generation of ROS contributes to errors

D. Deamination of cytosines and 5-methylcytosines contribute to errors

B. Endogenous agents are responsible for 3 errors per 100 cells per day

56

All of the following statements are true regarding DNA repair except...

A. Error-free repair restores DNA to its undamaged state

B. error-prone repair restores DNA to an improved but still modified state

C. Certain polymerases can bypass lesions that would otherwise block replication

D. If DNA damage is extensive, the cell will always undergo necrosis

D. If DNA damage is extensive, the cell will always undergo necrosis

57

Radiometric chemicals are defined as...

A. Those that are mutagenic to germ cells but not somatic cells

B. those that are mainly in the S-phase of the cell cycle

C. Those that are mutagenic to somatic cells but not germ cells

D. Those that are mutagenic in all stages of the cell cycle

D. Those that are mutagenic in all stages of the cell cycle

58

The battle between DNA repair and DNA replication is regulated towards the repair side by the presence of...

A. H-Ras

B. EGFR

C. p53

D. PDGF

C. p53

59

The male germ cell that can accumulate genetic change is...

A. Spermatogonial stem cell

B. spermatocyte

C. Spermatid

D. Spermatozoa

A. Spermatogonial stem cell

60

Which of the following are true?

A. Chromosomal abnormalities caused by ionizing radiation are caused by errors in DNA replication on a damaged DNA template

B. The oocyte is resistant to the formation of mutations by nonradiometric chemicals

C. The oocyte is resistant to the mutagenic effects of radiation

D. None of the above

B. The oocyte is resistant to the formation of mutations by nonradiometric chemicals

61

Aneuploidy has been assoc w/...

A. Griseofulvin and colchicine

B. amoxicillin and cephalexin

C. Methicillin and cephalotoxin

D. All of the above

A. Griseofulvin and colchicine

62

In genetic toxicity testing, the move from short-term tests to more complicated mammalian tests has an associated increase in...

A. Cost

B. Time

C. Relevance to humans

D. All of the above

D. All of the above

63

Which of the following is true of both genotoxic and non-genotoxic carcinogens?

A. Mutagenicity

B. no theoretical threshold

C. Tumorigenicity is dose responsive

D. No direct DNA damage

C. Tumorigenicity is dose responsive

64

Which of the following is a common characteristic of both the initiation and progression stages of chemical carcinogenesis?

A. Reversibility

B. Irreversibility

C. Multiple hits are necessary

D. Can be genotoxic or nongenotoxic

B. Irreversibility

65

All of the following are direct acting carcinogens except...

A. Sulfur mustards

B. methyl methanesulfonate

C. Bis (chloromethyl) ether

D. N-nitrosamines

D. N-nitrosamines

66

All of the following statements are generally true of direct-acting chemical carcinogens except...

A. They are highly species specific

B. They test positive in the Ames test without metabolic activation

C. They include epoxides and imines

D. They include chemotherapeutic drugs

A. They are highly species specific

67

Chloroform-induced liver tumors are postulated to form via which mechanism?

A. Oxidative stress

B. cytotoxicity

C. Hormonal

D. Receptor mediated

B. cytotoxicity

68

The gold standard for determining whether chemicals have the potential to cause cancer in humans is...

A. Ames test

B. mouse lymphoma assay

C. Chinese hamster ovary assay

D. 2 year study in lab rodents

D. 2 year study in lab rodents

69

Which of the following is true of asbestos?

A. Its asso w/ lung cancer is greatly increased in the presence of cigarette smoke

B. it causes only peritoneal mesothelioma

C. It causes cancer by DNA adduct formation

D. It is not asso w/ any other lung injury except neoplasms

A. Its asso w/ lung cancer is greatly increased in the presence of cigarette smoke

70

A test that has a greater than 85% concordance with the 2-year rodent bioassay is...

A. In vitro prokaryote mutagenesis

B. Syrian hamster embryo

C. Mouse lymphoma assay

D. Chinese hamster ovary

B. Syrian hamster embryo

71

All of the following are examples of genotoxicity and not mutagenicity except...

A. Unscheduled DNA synthesis

B. Sister chromatid exchange

C. Purine transition

D. DNA strand breaks

C. Purine transition

72

Which of the following statements are true regarding a forward mutation assay?

A. The Ames test is an example

B. It has greater than 95% concordance with the 2 year rodent carcinogenicity test

C. The response is usually broader than a reverse mutation assay

D. It directly measures chemical adducts to DNA

C. The response is usually broader than a reverse mutation assay

73

A membrane-bound structure that is a simple indicator of chromosome damage is...

A. ER

B. Micronucleus

C. Microsome

D. Histone

B. Micronucleus

74

The difference between mutagenic and genotoxic is...

A. Genotoxicity only causes birth defects

B. Mutagenicity produces transmissible genetic alterations

C. Mutagenicity only refers to chemicals and not ionizing radiation

D. Genotoxicity produces transmissible genetic alterations.

B. Mutagenicity produces transmissible genetic alterations

75

Which of the following statements is true?

A. Structure-activity relationships have been of little value in predicting mutagenesis

B. Nongenotoxic chemicals can be species specific

C. There is no statistical difference in the frequency of chromosomal aberrations between human smokers and nonsmokers

D. Chromosomal aberrations have not been shown to increase with age in humans


C. There is no statistical difference in the frequency of chromosomal aberrations between human smokers and nonsmokers