Exam 1; Neoplasia II

Question 1

This refers to the process in which portions of a malignant break free and travel to distant sites where they form new tumor masses; establishes a tumor as malignant

Answer 1

metastasis

Question 2

The ability to metastasize depends on what

Answer 2

the type of tumor; some readily metastasize while others rarely do

Question 3

Approximately what percentage of newly diagnosed patients with solid tumors present with metastases

Answer 3

30%

Question 4

In general the greater the what, that greater the tendency to metatasize

Answer 4

anaplasia (less differentiated)

Question 5

What are the three pathways in which malignancies spread

Answer 5

seeding within the body cavities; peritoneal cavity
lymphatic spread
hematogenous spread

Question 6

In the US, there were an estimated how many new cases of cancer and how many deaths

Answer 6

1.66 mil new cases

589K deaths

Question 7

What differs about the rates of lung cancer

Answer 7

lung cancer rates have leveled off for men but have increased in women

Question 8

Overall, what are the stats about cancer deather

Answer 8

substantial increase in death in males, but a slight decrease in females; pap smears

Question 9

What is the proportion of cancer risk attributed to environmental sources

Answer 9

roughly 2/3rds

Question 10

In general, cancer frequency increases with what

Answer 10

Age
most ≥55 years of age
accumulation of mutations and/or decrease of immune competence

Question 11

What percentage of deaths among children does cancer attest for

Answer 11

10%

Question 12

Is cancer a heredity disease?

Answer 12

There are pre-disposing factors for some cancer, but well-defined genetic influences identified in only a few types

Question 13

What are the three broad categories of genetic predisposition to cancer

Answer 13

inherited cancer syndromes
familial cancers
defective DNA repair

Question 14

Inherited cancer syndromes are usually due to what

Answer 14

a single gene mutation and generally show autosomal dominant transmission

Question 15

What are some examples of inherited cancer syndromes

Answer 15

retinoblastoma
familial adenomatous polyposis
multiple endocrine neoplasia

Question 16

Which types of cancers have been shown to occur in familial patterns

Answer 16

colon
breast
ovarian
brain

Question 17

Probably no more than what percentage of all humans cancers have an identifiable heritable basis

Answer 17

5-10%

Question 18

What are some examples of acquired preneoplastic disorders (persistent regenerative cell replication)

Answer 18

squamous metaplasia and dysplasia of bronchial mucosa
endometrial hyperplasia and dysplastic proliferations
leukoplakia of the oral mucosa, vulva, or penis
villous adenomas of the colon

Question 19

This lies at the heart of carcinogenesis; the fact that most cancers are clonal proliferations, suggest s that tumors arise from one genetically altered cel

Answer 19

nonlethal genetic damage

Question 20

What are the three classes of normal regulatory genes that are the principal targets of genetic damage

Answer 20

protoncogenes
cancer suppressor genes
apoptosis regulatory genes

Question 21

These genes are also important in carcinogenesis; if these genes are disabled, the frequency of mutations increases, and the rate of neoplastic transformation increases

Answer 21

DNA repair genes

Question 22

Carcinogenesis is what kind of process

Answer 22

MULTI-STEP both phenotypically and genetically

Question 23

These are proteins that are similar to normal cellular proteins derived from proto-oncogenes, but lack regulation

Answer 23

oncogenes - oncoproteins

Question 24

protooncogenes are transformed to oncogenes via what two mechanisms

Answer 24

structural mutation of the gene, resulting in an abnormal product
altered regulation of gene expression, resulting in increased production of a normal growth-promoting protein

Question 25

Mutations and overexpression of these have been documented; this makes cancer cells hyper responsive to even normal levels

Answer 25

growth factors

Question 26

Overexertion of these have been found in both SCC of the lung and some breast cancers

Answer 26

overexpression of growth factor receptors; particularly the epidermal growth factor receptor family

Question 27

Approx. 30% of all human tumor contain a mutated this

Answer 27

RAS oncogene; signal transduction pathway

mutated to be always on, therefore stimulating constant cell proliferation

Question 28

What is the most commonly affected nuclear transcription factor

Answer 28

MYC

Question 29

MYC gene dysregulation leads to this

Answer 29

overexpression, leading in continuous activation of cyclin dependent kinases, driving the cells to divide
also, repression of CDK inhibitors

Question 30

These are important in determining whether a cell is going to enter the cell cycle, and this dysregulation appears to favor cell proliferation

Answer 30

cyclin dependent kinases (CDK)

Question 31

What is the activity of CDKs regulated by, and if these are dysregulated, what occurs

Answer 31

CDK inhibitors

if dysregulated, proliferation occurs

Question 32

These inhibit cell proliferation, the first one discovered was Rb gene (retinoblastoma)

Answer 32

tumor supressor genes

Question 33

What is the “two-hit” hypothesis

Answer 33

two mutations (“hits”) in the (Rb) genome of a cell are required to induce retinoblastoma

Question 34

What occurs most often in familial cases of retinoblastoma

Answer 34

a child that inherits one detective copy of Rb, its very likely that the second mutation will develop

Question 35

What is the mechanism of Rb

Answer 35

Rb is a DNA-binding protein that is a key player in the regulation of the cell cycle. It binds DNA TFs and then released them trigger DNA synthesis, if Rb is mutated the cell cycle “essentially doesn’t have any brakes”

Question 36

This is the single most common target for genetic alteration in human tumors, homozygous loss of it is found in virtually every type of cancer

Answer 36

TP53

Question 37

What is the mechanism of TP53

Answer 37

TP53 normally acts in the nucleus to inhibit cell cycle progression, when DNA is damaged, TP53 accumulates, inhibiting cell proliferation and allowing time for DNA repair. If the DNA cannot be repaired, TP53 induces apoptotic genes. Without normal TP53, the cell incorporates mutations in its genome and ultimately cancer forms

Question 38

This is an inherited defect of one TP53 allele

Answer 38

Li-Fraumeni syndrome