H7

Question 1

Define carcinogenesis

Answer 1

Process which results in the transformation of normal cells to neoplastic cells by causing permanent genetic alterations

Question 2

What is a carcinogen?

Answer 2

• An agent known or suspected to participate in the causation of tumours, they are mutagenic (can cause genetic mutations)
• E.g] chemicals, viruses, radiation, hormones,
  bacteria, fungi, parasites

Question 3

What is the multistep hypothesis?

Answer 3

Often more than one carcinogen is necessary to produce tumours and the process occurs in several discrete steps.

Question 4

What are the characteristics of a neoplastic cell?

Answer 4

○ Evading apoptosis.
○ Self-sufficiency in growth signals.
○ Sustained angiogenesis.
○ Insensitivity to anti-growth signals.
○ Tissue invasion and metastases.
○ Limitless replicative potential.

Question 5

What are the main Cellular and Molecular Events that occur during carcinogenesis?

Answer 5

• Non-lethal genetic damage is central to the process of carcinogenesis.
• Genetic damage can be acquired or inherited.
• The main target of genetic damage are regulatory genes.
• The damaged cell then expands, forming cells with the same defect-clonal expansion.

Question 6

What are 4 regulatory genes?

Answer 6

○ Growth-promoting proto-oncogenes.
○ Growth-inhibiting cancer suppressor genes.
○ Genes that regulate apoptosis.
○ DNA repair genes.

Question 7

The function of which 3 groups are affected by malignancy?

Answer 7

proto-oncogenes, tumour suppressor genes and regulators of apoptosis

Question 8

What is the normal function of proto-oncogenes?

Answer 8

They are genes that code for proteins that are involved in the pathways that stimulate cell division

Question 9

How can proto-oncogenes cause malignancy?

Answer 9

Overactivity or “gain of function” of a proto-oncogene over-promotes cell division and proliferation

Question 10

What is the activation of proto-oncogenes?

Answer 10

Change from proto-oncogene to oncogene

Question 11

What are the 2 ways that proto-oncogenes can be activated?

Answer 11

• Changes in the structure of the gene, resulting in the synthesis of an abnormal gene product having aberrant function
• Changes in regulation of gene expression, resulting in enhanced or inappropriate production of the structurally normal growth-promoting protein

Question 12

What is the normal function of tumour suppressor genes?

Answer 12

Normally regulate the cells from over-proliferating

Question 13

How is the function of tumour suppressor genes affected by malignancy?

Answer 13

• Mutates and loses its function leading to loss of negative regulatory function.
• Allows proliferation to carry on unopposed

Question 14

How is the function of apoptosis affected by malignancy?

Answer 14

If this pathway is “switched off” then cells accumulate as a result of failure to die, rather than excessive proliferation

Question 15

Name 2 types of heamatological malignancies

Answer 15

leukaemia and lymphoma

Question 16

Define leukaemia

Answer 16

A malignant progressive disease in which the bone marrow and/or other blood-forming organs produce increased numbers or abnormal blood-forming cells

Question 17

Define lymphoma

Answer 17

Neoplastic proliferation of lymphoid cells

Question 18

What is acute leukamia?

Answer 18

Implies a proliferation of cells at the early stage of

development

Question 19

What is chronic leukaemia?

Answer 19

○ Cells are able to mature.
○ Often lose normal function.
○ Accumulate due to failure of apoptosis mechanisms

Question 20

What are the 2 types of lymphoma?

Answer 20

• Hodgkin (has Reed Stenberg cells)

- Non-Hodgkin lymphomas