Carcinogens

Question 1

Neoplasia

Answer 1

heritably altered, relatively autonomous growth of tissue

Question 2

Benign–tissue of origin + –oma

Answer 2

fibroma, (connective tissue)
lipoma, (fatty lump often situated between skin and underlying muscle layer)
adenoma (starts in gland-like cells of the epithelial tissue (thin layer of tissue that covers organs, glands, and other structures within the body))

Question 3

common abnormal regulation of gene expression in cancer cells

Answer 3

Increased expression of onco genes and decrease of tumor suppression genes

Question 4

mesenchymal tissue origin —>sarcoma

Answer 4

fibrosarcoma;
osteosarcoma;
liposarcoma

Question 5

ectodermal tissue origin (epithelial)–> X + carcinoma;

Answer 5

epdemoid carcinoma;
hepatocellular carcinoma,
gastric adenocarcinoma

Question 6

Carcinogen

Answer 6

Carcinogen—an agent whose administration to previously untreated animals
leads to a statistically significant increased incidence of neoplasms as compared to control animals.

Question 7

Sequence of Neoplasia

Answer 7

Initiation
Promotion
Progression

Question 8

Initiation

Answer 8

a. requires one or more rounds of cell division for the fixation of the process
b. metabolism and regulation of metabolism critical - some populations are therefore more susceptible GSTM1 important for detoxing PAHs
c. DNA interaction can occur spontaneously—promotion/progression are the rate limiting steps (Uv light)
d. activates “oncogenes” or inactivates “tumor suppressor” genes (TP53 is a common tumor suppressor gene)

Question 9

Promotion

Answer 9

a. no direct interaction with DNA (just ilicest signaling that causes overexpression of cancer genes)
b. metabolism not required for effectiveness
c. Reversible
d. dependent upon continued administration of promoting agent

Question 10

Progression

Answer 10

transition from early progeny of initiated cells to malignant cell population.

Question 11

Genotoxicity-

Answer 11

direct interaction with DNA
Problematic when DNA lesions aren’t repaired and are translated into next step
Lesions often get fixed but when they don’t its the problem
But the initiation of lesions is what we base risk calculations on.

Question 12

Progression characteristics

Answer 12

Induce chromosomal aberrations

Question 13

chromosomal aberrations through breaks in DNA.

Answer 13

Clastogenic

Question 14

Progression Mechanisms

Answer 14

1. inhibit DNA repair
2. topoisomerase activity
3. gene amplification
4. Altered telomere integrity

Question 15

complete carcinogen

Answer 15

can promote all three steps.
initiation, Promotion, progression.

Question 16

nongenetic cancer-causing mechanisms

Answer 16

a. oxidative stress (Oxigen is binding DNA not the chemical but the chemical is increasing the amount of Oxigen near DNA)
b. sustained tissue damage. (increased cell division leads to more spontaneous mutations, which increases cancer potential.)

Question 17

Epidemiology

Answer 17

findings from observation rather than experimentation

Question 18

Types of Epidemiology studies

Answer 18

Retrospective Studies
Prospective studies

Question 19

IARC

Answer 19

International Agency for Research on Cancer

Question 20

IARC CLASS 1

Answer 20

Agent is carcinogenic
Sufficient human evidence

Question 21

IARC CLASS 2A

Answer 21

Agent is probably carcinogenic
Sufficient animal evidence
limited human evidence

Question 22

IARC CLASS 2B

Answer 22

Agent is possibly carcinogenic
Sufficient animal evidence
limited or inadequate human evidence

Question 23

IARC CLASS 3

Answer 23

agent is not classifiable

Question 24

IARC CLASS 4

Answer 24

Agent is probably not carcinogenic
inadequate animal evidence
inadequate human evidence

Question 25

Sufficient evidence

Answer 25

causal relationship with epidemiology data necessary

Question 26

Limited evidence

Answer 26

causal, but chance bias and confounding variables cannot be excluded

Question 27

Inadequate evidence

Answer 27

a. few pertinent data
b. studies show association, but did not exclude variables
c. studies did not show evidence of cancer

Question 28

*QSARs

Answer 28

quantitative structural activity relationships.
(statistical empirical models that relate a quantitative description of chemical structure features of a series of molecules to the responses those molecules show in an experimental system.)

Question 29

ways to graph predicted cancer risk

Answer 29

Hockey stick regression versus extrapolating back to zero.

Question 30

overnutrition and high fat diets can…

Answer 30

lead to Promotion of cancer.

Question 31

Endogenous hormone production

Answer 31

can lead to cancer in 4th decade mothers

Question 32

common exogenous cause of human cancer?

Answer 32

Tabaco. 85-90% of lung cancer cases and 30% of all cancer deaths.

Question 33

Chemical Carcinogenesis Resulting from Medical Therapy and Diagnosis

Answer 33

Synthetic Estrogens
8-16 x increase in mammary cancer –post menopausal