Neoplasia 3 8-10-15 Flashcards Preview

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Flashcards in Neoplasia 3 8-10-15 Deck (28):
1

What do carcinogenic agents do?

inflict genetic damage
-react with nucleic acids (RNA, DNA) and or proteins

2

What are direct acting vs indirect acting chemical carcinogens?

1. direct acting
-require no metabolic conversion
-ex: cancer chemotherapeutics)alkylating agents)

2. Indirect
-require metabolic conversion to become ultimate carcinogens
-ex:
-polycyclic hydrocarbons:
a. benzo(a) pyrene formed in combustion of tobacco
b. animal fats

- aromatic amines, azo dyes
a. B-naphthylamine in dye and rubber industries


*some people have enzymes that are really robust

3

What do promoters do to carcinogenicity?

compounds which themselves are non tumorigenic however they
*facilitate the induction of cell proliferation
"initiation-promotion" sequence

-some chemical carcinogens may act in concert with viruses or radiation to induce neoplasms

4

vinyl chloride

angiosarcoma of the liver

5

Nitrosamine in smoked foods

stomach cancer

6

asbestos

mesothelioma and bronchogenic carcinoma

7

Arsenic

squamous cell carcinoma of the skin

8

naphthylamine dyes

urothelial carcinoma of the bladder

9

aflatoxin B

hepatocellular carcinoma (primary liver cancer)

10

cigarette smoke

carcinoma of the oropharynx, lung, esophagus, kidney and bladder

11

What are sources of radiation carcinogens?

-sunlight-ultraviolet radiation
-x-rays
-nuclear fusion/ionizing radiation
-fission by-products
-radionuclides

12

What does ionizing radiation do?

results in chromosome breakage, translocations, point mutations, which leads to genetic damage and carcinogenesis

-associated with papillary carcinoma of the thyroid

13

What does UV light do?

damages DNA by forming pyrimidine dimers-this process is repaired by the nucleotide excision repair pathway

-associated cancers-skin squamous cell carcinoma, basal cell carcinoma, melanoma

14

Is radiation initiation reversible is continued exposure additive

-irreversible
-additive
-radiation carcinogenesis has a long latent period

15

xeroderma pigmentosum

autosomal recessive syndrome of defective DNA repair
-defect in nucleotide excision repair pathway
-markedly increased predisposition to skin cancer

16

What types of microbial things cause cancer?

1. RNA viruses
-T-cell lymphotropic virus (HTLV-1)
-->T cell leukemia/ lymphoma

2. DNA viruses
-HPV
--->benign warts and cervical cancer
-Epstein Barr Virus
--->burkitt lymphoma, nasopharyngeal carcinoma
-Hep B and C virus
-->hepatocellular carcinoma

3. Bacteria
-Heliobacter pylori
-Gastric adenocarcinoma, MALT lymphoma

17

How do cancers evade immune system?

-fail to express HLA class 1 and escape CTL(cytotoxic t lymphocytes) attack
-eliminate strong immunogenic subclone
-suppress the host immune responses-->secrete TGF B, Expressing FasL and inducing immune cell apoptosis; activating regulatory t cells
-producing a thicker coat of glycocalyx molecules blocking access to immune cells

18

What are 3 effects tumors have on the host?

1. compress adjacent tissue and ulcerate through surfaces

2. can produce hormones

3. cancer cachexia-loss of body fat, lean body mass, weakness, anorexia, anemia

19

What is cancer cachexia? What cytokines mediate it? Is there treatment?

-loss of body fat, lean body mass
-weakness, anorexia, anemia

cytokine mediated
-TNF
-proteolysis inducing factor

-no satisfactory treatment-neoplasm cannot be removed

20

Paraneoplastic Syndrom

symptoms complexes that cannot be readily explained by local or distant spread
-hormone elaboration not indigenous to tumor parenchyma

21

What is grading based on?

cytologic differentiation of the tumor cells to estimate the aggressiveness of the tumor
1. degree of cellular differentiation
2. degree of cellular pleomorphism
3. degree of loss of normal architecture
4. mitotic index

22

What is staging based (TNM system) on?

1. size of primary tumor (T1, T2, T3, T4)
2. Extent of spread to lymph nodes (NO, N1 (regional), N2, N3)
3. presence or absence of metastasis (M0 or M1)

23

Which is of greater clinical significance grading or staging?

staging
exept
-prostate cancer, chondrosarcoma

24

What are some methods that aid diagnosis?

1. histological and cytological examination (tissue vs cell)
2. histoimmunochemistry
3. biochemical studies
4. ultrastructural studies (electron microscopy)
5. molecular biology studies

25

What do you use biochemical studies for?

detection of tumor associated markers
-know they had this type of cancer, check for recurrence

26

What does Alpha fetoprotein determine?

-liver carcinomas
-tumor of yolk sac remnants
-gonadal tumors

27

what does carcinoembryonic antigen determine?

colon, pancreas, lung, stomach, breast

28

What does molecular analysis of tumors play a role in?

**Diagnosis
-prognosis
-detection of minimal residual disease
-diagnosis of hereditary predisposition to cancer
-therapeutics