9. Fundamentals of Neoplasia

Question 1

Where does most of the neoplasias arise from?

Answer 1

From epithelium (90%). The remainder arise from mesenchymal cells.

Question 2

What is carcinogenesis?

Answer 2

A multistep process involving a sequence of initiation (mutation) followed by promotion (proliferation).

Question 3

What are initiators?

Answer 3

They are direct-acting chemical carcinogens. These are mutagens that cause cancer directly by modifying DNA.

Question 4

What are promotors?

Answer 4

They cause cellular proliferation of mutated (initiated) cells. Proliferation of a mutated cell may lead to accumulation of additional mutations.

Question 5

What do nitrosamines cause?

Answer 5

Gastric Cancer.

Question 6

What do polycylic aromatic hydrocarbons cause?

Answer 6

Bronchogenic carcinoma.

Question 7

What does asbestos cause?

Answer 7

Bronchogenic carcinoma, mesothelioma.

Question 8

What does chromium and nickel cause?

Answer 8

Bronchogenic carcinoma.

Question 9

What does arsenic cause?

Answer 9

Squamous cell carcinomas of skin and lung, angiosarcoma of liver.

Question 10

What does vinyl chloride cause?

Answer 10

Angiosarcoma of liver.

Question 11

What does aromatic amines and azo dyes cause?

Answer 11

Hepatocellular carcinoma.

Question 12

What does alkalating agents cause?

Answer 12

Leukemia, lymphoma, other cancers.

Question 13

What does benzene cause?

Answer 13

Leukemia.

Question 14

What does napthylamine cause?

Answer 14

Bladder cancer.

Question 15

What method employs bacteria to test potential carcinogens?

Answer 15

Ames test.

Question 16

What is the effect of ultraviolet radiation on cells?

Answer 16

Produces pyrimidine dimers in DNA leading to transcriptional errors and mutations of onogenes and tumor suppressor geners.

Question 17

What is Xeroderma Pimentosum?

Answer 17

Autosomal recessive inherited defect in DNA repair; they can’t repair the pyrimidine dimers caused by UV light.

Question 18

What is the effect of ionizing radiation on cells?

Answer 18

They cause cross-linking and chain breaks in nucleic acids.

Question 19

What stage of cell cycle is most vulnerable to ionizing radiation?

Answer 19

Cells in mitosis or G2 of the cell cycle.

Question 20

What are the sources of ionizing radiation?

Answer 20

X-rays, gamma rays, alpha and beta particles, protons and neutrons, atomic bombs and uranium miners.

Question 21

Give an example of RNA oncogenic virus.

Answer 21

The human T-cell leukemia virus (HTLV-1) causes adult T-cell leukemia/lymphoma.

Question 22

What are four DNA oncogenic virus?

Answer 22

I. Hepatitis B virus. II. Epstein-Barr virus (EBV). III. Human papilloma virus (HPV). IV. Kaposi-sarcoma-associated herpesvirus (HHV8).

Question 23

What type of cancer does Hepatitis B virus cause?

Answer 23

Hepatocellular carcinoma.

Question 24

What type of cancer does Epstein-Barr virus (EBV)?

Answer 24

I. Burkitt lymphoma. II. B-cell lymphomas in immunsuppressed patients. III. Nasopharyngeal carcinoma.

Question 25

What type of cancer deos Human papilloma virus (HPV)?

Answer 25

I. Benign squamous papillomas (warts). II. Cervical cancer.

Question 26

What does p53 tumor suppresor gene do?

Answer 26

Prevents a cell with damaged DNA from entering S-phase by promoting apoptosis in said cells by stimulating bax synthesis.

Question 27

What does Rb tumor suppresor gene do?

Answer 27

Prevents the cell from entering S-phase unti the appropriate growth signals are present.

Question 28

What is Knudson's "two hit hypothesis"?

Answer 28

Both tumor suppresor genes must be inactivated for oncogenesis.

Question 29

What would be an example of a first hit in Knudson's hypothesis?

Answer 29

An inherited germ-line mutation.

Question 30

What would be an example of a second hit in Knudson's hypothesis?

Answer 30

An acquired somatic mutation.

Question 31

What are two examples of inherited germ-line mutation?

Answer 31

Familial retinoblastoma and Li-Fraumini syndrome.

Question 32

What is Familial retinoblastoma?

Answer 32

Caused by Germ-line muation of Rb on chromosome 13, it causes high rate of retinoblastoma and osteosarcoma.

Question 33

What is Li-Fraumini syndrome?

Answer 33

Caused by Germ-line muation of p53 on chromosome 17, it causes high rate of many types of tumors.

Question 34

What does bcl-2 do?

Answer 34

Prevents apoptosis. It is overexpressed in follicular lymphomas t(14:18) = Chrom14 - immunoglobulin heavy chain gene and Chrom18 - bcl-2 gene.

Question 35

Which four genes promote apoptosis?

Answer 35

bax, bad, bcl-xS, bid

Question 36

What does c-myc do?

Answer 36

Promotes cellular proliferation.

Question 37

What diseases are associated with alpha-fetoprotein (AFP)?

Answer 37

Hepatoma, nonseminomatous testicular germ-cell tumors.

Question 38

What diseases are associated with beta human chorionic gonadotropin (hCG)?

Answer 38

Trophoblastic tumors, choriocarcinoma.

Question 39

What diseases are associated with cacitonin?

Answer 39

Medullary carcinoma of the thyroid.

Question 40

What diseases are associated with carcinoembryonic antigen (CEA)?

Answer 40

Carcinomas of the lung, pancreas, stomach, breast and colon.

Question 41

What diseases are associated with alpha-fetoprotein CA-125?

Answer 41

Ovarian cancer.

Question 42

What diseases are associated with CA19-9?

Answer 42

Pancreatic cancer.

Question 43

What diseases are associated with placental alkaline phosphatase?

Answer 43

Seminoma.

Question 44

What diseases are associated with PSA?

Answer 44

Prostate cancer.

Question 45

What diseases are associated with prostatic acid phosphatase?

Answer 45

Prostate cancer.

Question 46

What does TNM staging system criteria stand for?

Answer 46

T: Size of the primary tumor. N: Extent of regional lymph node spread. M: Presence of metastatic disease.

Question 47

What is the most common rout of spread for epithelieal carcinomas?

Answer 47

Lymphatic spread.

Question 48

Which carcinomas spread through the blood?

Answer 48

Most sarcomas, renal cell carcinoma, hepatocellular carcinomas, follicular carcinoma of the thyroid, choriocarcinoma.

Question 49

Which serological marker is associated with melanomas and neural tumors?

Answer 49

S100.