Module 01 - Introduction to Evolutionary Biology of Cancer Flashcards
(24 cards)
What is Cancer?
Collection of related disease where some of the body’s cell begin to divide without stopping and spread into surrounding tissues
What is the origin of the word cancer ?
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
True of False: Research conducted in the 18th century provided some evidence that cervical cancer is a sexually transmitted cancer
True
True or False: Chemical weapons contributed to the development of chemotherapy
True
True or False: Herceptin a monoclonal antibody drug aimed at hormone-sensitive breast cancer was licensed in 1998
True
Who developed the idea of cancer growth as a Darwinian Process?
Peter Nowell, UPenn
What is natural selection?
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
What are the 3 requirements for evolution by natural selection?
1- Variation in the population
2- Variation must be heritable
3- Variation must influence survival or reproductive rates (fitness) of members of the population
What is a “clone”?
group of cells that are derived from the same parent cell
what is a “sub-clone”?
Progeny of a mutant cell arising from a clone
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?
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
What are selective pressures?
Any environmental factors or conditions that diminish the reproductive success of certain variants of a population, thus contributing to natural selection
What are the 3 types of evolution pathways?
Divergent evolution
Convergent evolution
Parallel evolution
What is Divergent Evolution? and give an example using tumour cells
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
What is Convergent Evolution? and give an example using tumour cells
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
What is Parallel Evolution? and give an example using tumour cells
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
Why is it important to understand evolutionary pathways in cancer?
Makes it easier to figure out where to target cancer treatment options if the mechanism of cell population growth are understood
What are the 4 major categories of tumour antigenic products?
mutated products
protein levels
glycolipids
oncogenic products
How have the old theories of cancer been replaced with new theories?
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
What are the 3 spheres of society cancer has impacted greatly?
economy (individual paying for treatment or universal healthcare, or time off work/available workforce)
health and well being (health costs)
Research (management, treatment, mechanisms)
What are mutated products?
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
How are abnormal protein levels antigenic?
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
How are glycolipids antigenic?
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
What are oncogenic products?
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
