Genes and Cancer

Question 1

What are the three gene types which are involved in cancer?

Answer 1

Oncogenes
Tumour suppressor genes
Cells that control apoptosis

Question 2

Describe oncogenes in terms of action on host cells

Answer 2

Incorporate DNA copy in their genomic RNA into host cells and transform host cells
Activation of oncogenes results in transformation of normal cells to neoplastic cells, causing gain of function

Question 3

What are the four functional groups of pathways that proto-oncogenes are responsible for?

Answer 3

Growth factors (PDGF)
Growth factor receptors
Signal transmission pathways (Ras)
Nuclear transcription factors (Myc)

Question 4

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

Answer 4

Gene amplification
Over expression of a gene/ expression at an inappropriate time
Point mutations on the oncogene
Gene rearrangement or translocation
Epigenetics

Question 5

What are the functions of tumour suppressor genes?

Answer 5

Regulation of the cell cycle/growth inhibition

Repair DNA damage/maintain genome integrity

Question 6

How do tumour suppressor genes stop working?

Answer 6

Point mutations
Loss of heterozygosity
Altered methylation
(requires hits to both alleles)

Question 7

What are the two ways that molecular mechanisms can interfere with apoptosis causing cancer?

Answer 7

Loss of expression of genes which mediate apoptosis (p53)

Up regulation of genes which block apoptosis

Question 8

Which gene is responsible for uncontrolled proliferation in chronic myeloid leukaemia?

Answer 8

BCR-ABL

Question 9

How is chronic myeloid leukaemia?

Answer 9

Bone marrow transplant

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