BIO1: What Makes A Cancer?

Question 1

Define cancer

Answer 1

Uncontrolled growth of abnormal cells in the body

Cancerous cells = malignant cells

Balance shifts towards proliferation + survival

Accumulation of abnormal cells

• Increase in division
• Decrease in cell death

Question 2

Define gene

Answer 2

Bit of inherited DNA that does a job

• encodes a protein
• genes control cell divison
  
  • response to environmental clues
  • tell cell to divide, die or do neither

Question 3

Define mutation

Answer 3

Change in genetic information

• additional, removal, swapping of nucleotides
• either harmful, beneficial or neutral
• Random - not controlled by cell

Question 4

What causes cells to divide?

Answer 4

Interactions of proteins + other cellular components

Question 5

What determines which proteins are present?

Answer 5

Genes

Question 6

Changes in gene sequences affect…

Answer 6

Protein function + protein abundance

Question 7

What is the function of proto-oncogenes?

Answer 7

• Increase cell division
• Decrease cell death

Question 8

What is the function of tumour suppressor genes?

Answer 8

• Decrease cell division
• Increase cell death

Question 9

Define proto-oncogene

Answer 9

Normal gene found in a cell

• Involved in cell death

Question 10

What happens if a mutation occurs in a proto-oncogene?

Answer 10

Gene is turned on when it shouldn’t

Proto-oncogenes can turn into a malfunctioning gene called an Oncogene, which can cause the uncontrollable growth of cancer cells

Question 11

Define oncogenes

Answer 11

Mutated forms of proto-oncogenes, a gene that causes cancer.

Question 12

Define tumour suppressor genes

Answer 12

A gene which makes proteins called a tumour suppressor protein that helps control cell growth + inhibit growth of cancer cells or tumour

• Mutations in TSG can cause cancer

Question 13

What is the 3rd class of important genes?

Answer 13

Genes that maintain DNA stability by repairing DNA + protecting against accumulation of mutations

Question 14

What are the hallmarks of cancer?

Answer 14

Question 15

Examples of tumour suppressor genes

Answer 15

• p53 (TP53, tumour protein 53)
• RB1 (retinoblastoma 1)

Question 16

Examples of Proto-oncogenes

Answer 16

• MYC
• RAS

Question 17

What are the cancer genes?

Answer 17

1. Proto-oncogene/oncogne
2. Tumour suppressor gene
3. Genes that encode for proteins that maintain DNA stability in repairing DNA + protecting against accumulation of mutations

Question 18

How do cells die?

Answer 18

Necrosis

Apoptosis

Question 19

What is necrosis?

Answer 19

Spillage of contents

• leads to inflammation
• caused by damage, infection, ischaemia + cancer

Question 20

What is apoptosis?

Answer 20

Programmed cell death

• orderly suicide
• cellular contents degraded + removed

Question 21

In apoptosis, cell proliferation is balanced by cell death

Where does apoptosis occur?

Answer 21

Tumours

• limiting growth rates
• intrinsic vs extrinsic pathways - induced fromw withi cells or immune cells

Question 22

How are cancer cells resistant to apoptosis (death)?

Answer 22

Upregulation of survival signals

Downregulation of pro-apoptotic signals

• should be a balance between pro + anti-apoptotic signals found on mitochondrial membrane

Question 23

How does necrosis promote cancer?

Answer 23

Impacts neighbouring cells

• proinflammatory signals release
• immune cells recruited which promote angiogenesis
• growth factors released which promote proliferation