Module 01 - Introduction to Evolutionary Biology of Cancer

Question 1

What is Cancer?

Answer 1

Collection of related disease where some of the body’s cell begin to divide without stopping and spread into surrounding tissues

Question 2

What is the origin of the word cancer ?

Answer 2

Carcinoma is the greek word for crab, it was used to describe tumours because of their round center and fingerlike projection.
Carcinoma was translated to cancer, the latin word for crab.
Another physician called tumours Oncos (greek for swelling, hence why oncologist

Question 3

True of False: Research conducted in the 18th century provided some evidence that cervical cancer is a sexually transmitted cancer

Answer 3

True

Question 4

True or False: Chemical weapons contributed to the development of chemotherapy

Answer 4

True

Question 5

True or False: Herceptin a monoclonal antibody drug aimed at hormone-sensitive breast cancer was licensed in 1998

Answer 5

True

Question 6

Who developed the idea of cancer growth as a Darwinian Process?

Answer 6

Peter Nowell, UPenn

Question 7

What is natural selection?

Answer 7

individuals with a favourable set of traits for their environments are more likely to survive and produce viable offspring than individuals with less favourable traits

Question 8

What are the 3 requirements for evolution by natural selection?

Answer 8

1- Variation in the population
2- Variation must be heritable
3- Variation must influence survival or reproductive rates (fitness) of members of the population

Question 9

What is a “clone”?

Answer 9

group of cells that are derived from the same parent cell

Question 10

what is a “sub-clone”?

Answer 10

Progeny of a mutant cell arising from a clone

Question 11

The outcomes of natural selection at the species level are very different from the outcomes of natural selection at the cellular level. What is this difference?

Answer 11

Evolution at the cellular level leads to decreased fitness of an organism as a whole - this is the opposite of evolution at the species level

Question 12

What are selective pressures?

Answer 12

Any environmental factors or conditions that diminish the reproductive success of certain variants of a population, thus contributing to natural selection

Question 13

What are the 3 types of evolution pathways?

Answer 13

Divergent evolution
Convergent evolution
Parallel evolution

Question 14

What is Divergent Evolution? and give an example using tumour cells

Answer 14

When population of a single species accumulate enough phenotypic differences to diversify and become separate species
– Constant cell division and growth result in subclones with different mutations = they are variant of each other and provide heterogeneity to tumours

Question 15

What is Convergent Evolution? and give an example using tumour cells

Answer 15

When two unrelated species develop analogous structure due to similar environmental selective pressures
– Evident when comparing mutations in subclones that have originated from different clones. While there are many possible mutations, there are also a select amount of genes that are most often mutated in a variety of cancers

Question 16

What is Parallel Evolution? and give an example using tumour cells

Answer 16

When two unrelated species evolved on a similar path to produce similar phenotypic traits throughout the entirety of their evolution
– Occurs when common mechanisms for growth and proliferation are seen acros tumour populations

Question 17

Why is it important to understand evolutionary pathways in cancer?

Answer 17

Makes it easier to figure out where to target cancer treatment options if the mechanism of cell population growth are understood

Question 18

What are the 4 major categories of tumour antigenic products?

Answer 18

mutated products
protein levels
glycolipids
oncogenic products

Question 19

How have the old theories of cancer been replaced with new theories?

Answer 19

Old theory described it as a disease of body fluids, which could be disrupted by many environmental and spiritual causes. Greater understanding of human anatomy and cellular physiology with time, particularly with the discovery of the genetic basis of cancer, shifted old theories toward new theories of cancer as a molecular process

Question 20

What are the 3 spheres of society cancer has impacted greatly?

Answer 20

economy (individual paying for treatment or universal healthcare, or time off work/available workforce)
health and well being (health costs)
Research (management, treatment, mechanisms)

Question 21

What are mutated products?

Answer 21

Mutations in genes favour uncontrolled growth and result in abnormal proteins which can be processed and displayed in the MHC class 1 or II pathway and recognized as foreign
cause: abnormal protein, ex: RAS

Question 22

How are abnormal protein levels antigenic?

Answer 22

Immune cells develop a tolerance to the low concentration of growth-related cell proteins. When these growth-related cell proteins are over-expressed in cancerous cells, the immune system is stimulated to mount an anticancer attack
Cause: abnormal expression of growth related proteins, ex: over-expression of HER2

Question 23

How are glycolipids antigenic?

Answer 23

Many cancerous cell types over-express normal or express abnormal cell surface glycated products to aid cell invasion
ex: ABO blood group glycoproteins are modified in oral cancer

Question 24

What are oncogenic products?

Answer 24

Virus-associated cancers, the viral proteins can be processed and presented to the immune cells together with MHC class I antigens. Highly immunogenic and cause strong immune response
Ex: E6and E7 proteins displayed in cervical cells infected by HPV