cancer as a genetic disease

Question 1

oncogenes definition

Answer 1

promote growth and proliferation; gain function

Question 2

dominant oncogenes

Answer 2

only one gene copy mutated; when active, override apoptosis

Question 3

oncogenic gene fusions in leukaemia

Answer 3

92 chromosomes→improper separation→45 (monosomy)/47 (trisomy)

Question 4

tumour suppressors definition

Answer 4

regulate cell division (G1→S and in S); if DNA damage, no division, leading to apoptosis or repair

Question 5

recessive tumour suppressors

Answer 5

both mutated copies (most can function normally with one non-mutated allele)

Question 6

Knudson’s 2-hit hypothesis

Answer 6

2 alleles: hit 1 causes a decrease in transcription rate but no phenotypic effect (point mutation); hit 2 causes a total loss of transcription so malignant potential (deletion)

Question 7

genetic disease causing a mutated tumour

Answer 7

genetic disease → age → malignant clone by mutations (e.g. aneupoloidy, translocation macro-deletions/insertions, point mutations) → polyclonal (tumour mutates)