Cancer

Question 1

Causes of cancer

Answer 1

• Environmental carcinogens
• Viral infections
• Genetic instability
• Inherited factors

Question 2

What was the first tumour-causing virus that was discovered?

Answer 2

Rous Sarcoma virus

Question 3

Why is RSV tumour-causing?

Answer 3

The presence of DNA sequences from the chicken genome - the v-src oncogene

Question 4

Which oncogene is associated with RSV?

Answer 4

v-src oncogene

Question 5

What does v-src encode?

Answer 5

An abnormally hyperactive version of tyrosine kinase

Question 6

What codes for a normal version of tyrosine kinase?

Answer 6

The c-src proto-oncogene

Question 7

What does the c-src proto-oncogene code for?

Answer 7

A normal version of tyrosine kinase

Question 8

What is chromosomal translocation?

Answer 8

The disruption, truncation or reassembly of genes on chromosomes

Question 9

What can chromosomal translocation of proto-oncogenes lead to?

Answer 9

Cancer

Question 10

Which chromosome is associated with chronic myeloid leukaemia?

Answer 10

The Philadelphia chromosome

Question 11

What translocation is taking place on the philadelphia chromosome?

Answer 11

BCR from chromosome 22

ABL from chromosome 9

Question 12

What is BCR-ABL?

Answer 12

Present on the translated chromosome, it encodes a hyperactive version of tyrosine kinase

Question 13

What does ABL code for?

Answer 13

Tyrosine kinase

Question 14

Examples of proto-oncogenes –> oncogene

Answer 14

ABL and BCR –> BCR-ABL

Question 15

What is a retinoblastoma?

Answer 15

A rare retinal tumour that can be either hereditary or non-hereditary

Question 16

When are retinoblastoma always hereditary?

Answer 16

When they are bilateral

Question 17

Hereditary of unilateral retinoblastomas

Answer 17

Can be either hereditary or non-hereditary

Question 18

What is retinoblastoma caused by?

Answer 18

Loss-of-function mutation in both alleles of a tumour suppressor gene - normally prevents cells from becoming cancerous

Question 19

Why might someone be more likely to acquire a tumour?

Answer 19

If hereditary, already have one mutation present so only need one more sporadic mutation

Question 20

What kind of mutation causes cancer from proto-oncogenes?

Answer 20

Dominant and gain-of-function mutations

Question 21

What kind of mutation causes cancer from tumour suppressor genes?

Answer 21

Recessive and loss-of-function mutations

Question 22

Which kind of genes do dominant, gain-of-function mutations affect?

Answer 22

Proto-oncogenes

Question 23

Name the 4 plasias

Answer 23

• Neoplasia
• Hyperplasia
• Metaplasia
• Dysplasia

Question 24

What is is neoplasia?

Answer 24

Invasive, abnormal tissue growth

Question 25

What is hyperplasia?

Answer 25

Tissue growth containing excessive number of cells

Question 26

What is metaplasia?

Answer 26

Tissue growth containing displaced and normal cells

A change in cell differentiation

Question 27

What is dysplasia?

Answer 27

Tissue growth containing cells that look abnormal under a microscope

Question 28

What is a benign tumour?

Answer 28

Tumour that is well-confined and local. Surrounded by a basement membrane so unlikely to spread

Question 29

What is a malignant tumour?

Answer 29

Tumour that breaks through the basement membrane and can spread

Question 30

What is metastasis?

Answer 30

The development of a secondary tumour at a distance from the primary growth

Question 31

What is anaplasia?

Answer 31

When cells only poorly differentiate