Lecture 1 - Intro

Question 1

What is cancer?

Answer 1

It is a collection of diseases that have the underlying features of uncontrolled growth and invasion.

Question 2

List the types of cancer

Answer 2

1. Carcinoma - epithelial (lung, liver, breast)
2. Sarcoma - connective tissue (bones, muscle, blood vessels)
3. Myeloma - Bone marrow (plasma cells)
4. Leukemia - bone marrow (white blood cells)
5. Lymphoma - lymph node/gland (spleen, tonsils)
6. -oma - benign tumours (lipoma, adenoma)

Question 3

Define Neoplasm.

Answer 3

It is defined as a new disorganised growth with net increased in number of dividing cells.

Question 4

What is a tumour?

Answer 4

It is a mass of abnormal cells.

Question 5

Define benign tumours

Answer 5

These tumours do not invade their surrounding nor spread beyond their initial site.

Question 6

Define malignant tumours

Answer 6

These tumours spread beyong their initial site and are the more dangerous.

Question 7

Define metastasis.

Answer 7

It is the invasion of a tumour to its surrounding tissue and spread beyond its initial site.

Question 8

Define carcinogenesis.

Answer 8

It is the process of forming a cancer.

Question 9

List the phases of cell cycle.

Answer 9

1. Gap 0 (Quiescent- resting cells)
2. Gap 1 (RNA and protein synthesis for S phase)
3. S phase (DNA synthesis)
4. Gap 2 (RNA and protein synthesis for M phase)
5. M Phase ( prophase, metaphase, anaphase and telophase)

Question 10

List the hallmarks of a cancer.

Answer 10

• Gain growth factor independence
• Insensitivity to growth inhibitor
• Proliferate without limit
• Avoid apoptosis
• Promote angiogenesis
• invade and metastasise

Question 11

Describe the hallmark 1- gain growth factor independence.

Answer 11

The cell loses requirement for growth factor to stimulate cell division. It means they gain an oncogene. The causes of this can be from secretion of growth factor, mutation in growth factor where it is always on or mutations of components in signalling pathways or transcription factors activated by growth factors

Question 12

What is an oncogene?

Answer 12

It is a gene which, when mutated or overexpressed can cause cancer.
Ras was one of the first oncogene discovered. The normal Ras (proto-oncogene) when activated, triggers other signaling events which lead to cell proliferation.
Other examples of oncogene are Bcr-Abl, myc, src and PI3. All of these gain independence from grow factors. Oncogenes are an important drug target as when blocked it will stop growth of cancer cells. Imatinib is a tyrosine kinase inhibitor that prevent growth factor signals.

Question 13

What is HER2?

Answer 13

It is an example of growth factor independence. HER2 positive cancer are more aggressive. Tratuzumab blocks the HER2 receptor.

Question 14

Describe hallmark 2 - insensitivity to growth inhibitors

Answer 14

The cell loses the control abnormal cell proliferation. It is normally the result of loss of tumour suppressor genes (pRb) or the upregulation of positive cell cycle regulators (CDC25)

Question 15

What do tumour suppressor genes do?

Answer 15

They perform the exact opposite of oncogenes, they stop tumours forming. They are normally involved in detecting DNA damage and mutations and then either trigger apoptosis or DNA repair. Examples of tumour suppressor genes are pRb, p53 and BRCA.

Question 16

Describe hallmark 3- proliferate without limit.

Answer 16

Most cells cannot proliferate more than 40-60 times and this is normally determined by the length of the telomere. Telomere normally shortens every time the cell divide exception being cancer cells and stem cells.

Tumours cells are effectively immortal because they rebuild telomeres using the enzyme telomerase.

Question 17

Describe hallmark 4 - avoid apoptosis

Answer 17

Apoptosis is normally triggered by DNA damage or viral infection, two things which can lead to the development of cancer. Chemotherapy and radiotherapy uses apoptosis to kill cancer cell.

There are 2 ways to avoid apoptosis; gain of function of pro survival factors suchs as Bcl2 or loss of function of apoptotic factors such as p53.

Question 18

Describe hallmark 5 - promote angiogenesis

Answer 18

Tumours normally stays small unless they secure a supply of blood. Increased blood supply allows continued growth due to more nutrients.
They promote new blood vessel growth by secreting angiogenic factors such as VEGF or FGF

Question 19

Describe hallmark 6 - Invasion and metastasis.

Answer 19

90% of death due to cancer is due to metastasis.
Malignant cancer cells acquire the ability to move and break away from the main tumour. The cells crawl through the ECM till they find a blood supply. These abilities can be acquired through the decreased expression of cell adhesion or secretion of proteases which break down ECM. Cells sometimes get into bloodstream and travel to a new site where a new tumour grow.

Question 20

How can cancer kill?

Answer 20

1. It interferes with normal organ function by blockage, deprivation of nutrients or pressure.
2. It can interferes with metabolic processes such as malnutrition, calcium changes, liver enzyme function, blood cell production or hormone production.
3. Muscle wasting.

Question 21

List the types of gene mutations.

Answer 21

1. Point mutations or small insertions or deletions.
2. Alteration in transcription/ splicing
3. Amplifications/ deletions of chromosomal regions.
4. Chromosomal translocation
5. Gains and losses of whole chromosomes.
6. Changes in DNA modification.

Question 22

What can cause DNA mutations?

Answer 22

• UV or other radiation
• free radicals produced during metabolic processes.
• Viruses
• Chemicals
• Copying/repair errors

Question 23

List the stages of cancer development.

Answer 23

1. Initiation (Mutations promote increased proliferation_
2. Promotion ( Further proliferation)
3. Tumour progression ( Growth and invasion of the tumour.

Question 24

How to improve survival rates?

Answer 24

Early detection, diagnosis and treatment is key

Risk factors such as smoking, alcohol, obesity, sedentary, diet (too much processed food), infections.