Lecture 15 3/18/24

Question 1

What are the components of a morphologic diagnosis for neoplasm?

Answer 1

-tissue
-tumor type
-whether it is metastatic

Question 2

What are the characteristics of the G1/S checkpoint?

Answer 2

-monitors DNA integrity
-irreversibly commits cell resources to DNA replication
-cell replication occurs independent to extracellular growth signals after this point

Question 3

What are the characteristics of the G2/M checkpoint?

Answer 3

-pre-mitotic checkpoint
-ensures that DNA replication is accurate before cell divides

Question 4

Which checkpoint is most important for carcinogenesis?

Answer 4

G1/S checkpoint

Question 5

What are the possible cell types, based on division?

Answer 5

-continuously dividing
-non-dividing
-quiescent/can be induced to divide

Question 6

What is the purpose of p53?

Answer 6

to stop cell division in cells with DNA damage and trigger either DNA repair or cell death

Question 7

Which irreversible DNA mutations can lead to cancer development?

Answer 7

-proto-oncogenes
-tumor suppressor genes
-DNA repair genes
-genes regulating apoptosis

Question 8

What are proto-oncogenes?

Answer 8

genes that promote autonomous cell growth

Question 9

What happens when proto-oncogenes are mutated?

Answer 9

-growth factors are over-produced
-growth factor receptors are always “on”
-cyclins are over-produced, allowing progression through cell cycle

Question 10

How many copies of a proto-oncogene must mutate to cause neoplasm?

Answer 10

one

Question 11

What are tumor suppressor genes?

Answer 11

genes that stop the cell cycle

Question 12

How many copies of a tumor suppressor gene must mutate to cause neoplasm?

Answer 12

two (both copies)

Question 13

What are the characteristics of familial cancer syndromes?

Answer 13

-mutated tumor suppressor gene is passed on to offspring
-only one additional mutation required to inactivate the gene
-cancer often occurs earlier in life

Question 14

What happens when DNA repair genes are mutated?

Answer 14

allows for the accumulation of more and more mutations in the cell genetics

Question 15

What happens when genes that regulate apoptosis are mutated?

Answer 15

cells with DNA damage are allowed to continue living

Question 16

What are the characteristics of multi-stage carcinogenesis?

Answer 16

-results from accumulation of mutations in a stepwise fashion over time
-nonlethal genetic damage is key
-tumor is formed by clonal expansion of a single precursor cell with genetic damage

Question 17

What are the characteristics of multi-stage carcinogenesis initiation?

Answer 17

-mutation of single gene
-irreversible

Question 18

What are the characteristics of multi-stage carcinogenesis promotion?

Answer 18

-proliferation of initiated cell in response to stimuli
-non-mutagenic
-reversible
-creates a proliferative environment

Question 19

What are the characteristics of multi-stage carcinogenesis progression?

Answer 19

-progression from benign to malignant
-accumulation of mutations and uncontrolled cell growth
-irreversible

Question 20

Which intrinsic factors can cause mutation?

Answer 20

-inherited
-mistakes
-reactive oxygen intermediates

Question 21

Which extrinsic factors can cause mutation?

Answer 21

-viruses
-chemical carcinogens
-radiation

Question 22

What are complete carcinogens?

Answer 22

carcinogens that can independently push a cell through initiation, promotion, and progression

Question 23

What is grading?

Answer 23

-histologic diagnosis that assesses degree of differentiation, number of mitoses, and architectural features
-links histologic/microscopic features with clinical aggressiveness

Question 24

What is staging?

Answer 24

-clinical diagnosis that assesses tumor size, degree of local invasion, lymph node involvement, and presence of distant metastases
-conveys extent of disease/neoplasia within the patient