Cancer - What is Cancer & Development Flashcards
Aoife (36 cards)
Cancer Terminology
Proliferation
The process of cell growth and cell division leading to the expansion of the cell population
Cancer Terminology
Differentiation
When early cells (for example stem cells or progenitor cells) give rise to specialised cells
Carcinogenesis
What is carcinogenesis
The process by which cancers are generated
Carcinogenesis
What does carcinogenesis result from
An accumulation of errors in vital regulatory pathways
Carcinogenesis
What is the core feature of cancer
Uncontrolled proliferation (cell division and expansion)
Carcinogenesis
What are normal cells subjected to that control cell growth and what happens to this during carcinogenesis
Internal and external inhibitory signals that control cell growth and this control is lost in carcinogenesis
Carcinogenesis
What is as important as increased proliferation for carcinogenesis and why
Decreased rate of cell death -> the longer a cell lives, the more likely for genetic errors to occur
Carcinogenesis
What are essential for a tumour to survive and what is the name for the growth of these
New blood vessels are essential for a tumour to survive. The growth of new blood vessels is called angiogenesis
Carcinogenesis
General carcinogenesis description
- carcinogenesis is a multi step mechanism
- results from an accumulation of errors in vital regulatory pathways
- uncontrolled proliferation (cell division and expansion) is the core feature of cancer
- normal cells are subject to internal and external inhibitory signals that control cell growth
- this control is lost during carcinogenesis
- cells multiply and acquire additional changes that give it a survival advantage
- these changes generate billions of cells
- decreased rate of cell death as important for carcinogenesis as increased proliferation as the longer a cell is alive, the more likely for genetic errors that generate cancer to occur
- new blood vessels are essential for tumour survival (angiogenesis)
what cancers are characterised with onset in childhood (2)
- Cancer of the eye
- Certain leukaemias
Lifestyle influences on cancer (6)
- Occupational cancers -> lab work, construction, radiographers etc…
- Free radical generation
- Carcinogens in cigarettes
- Mutations in repressor genes and oncogenes
- Inherited predisposition
- Diet
Cancer & genes
Cancers are generated by what (in terms of genes)
Changes in genes that have a role in controlling cell growth
Cancer & genes
What do gene changes in cancer cause
Changes in cell signalling pathways with the end result being uncontrolled growth
Cancer & genes
Definition of a repressor gene
A gene whose protein product inhibits a cell function
Cancer & genes
Definition of an Oncogene
A genes whose protein product contributes to carginogenesis
Cancer & genes
Definition of a Proto-oncogene
A gene present in normal cells that can as a result of a mutation become an oncogene
The 2 strategies that cancer cells use to make energy from sugar in the tumour environment
- Aerobic respiration: cells use both sugar molecules and oxygen to make energy
- Anaerobic respiration: cells that are anaerobic use sugars to make energy -> formation of toxic lactic acid which kills nearby healthy cells, making room for more cancer cells
5 cancer risk factors
- Smoking
- Diet
- Sex hormones
- Increasing age
- Family history
What is the most common cancer in Ireland and why is it so prevalent
Skin cancer (26%)
We have a thinner layer of the ozone layer
Cancer risk factors
Smoking as a risk factor for cancer
- USA: 30% of cancer deaths due to smoking
- Non smoker who lives w a smoker has a 30% higher risk of dying from lung cancer than when living w a non smoker
- Smoking linked to increase in lung, mouth, oesophagus, pharynx, kidney, bladder cancer
- Over 40 potential carvinogens isolated from tobacco
- 20 year gap between increased tobacco consumption and lung cancer changes
Cancer risk factors
Free radicals as a risk factor for cancer
- They are ions/ molecules with unpaired electrons
- They are highly reactive and likely to take part in chemical rxns
- Superoxide and hydroxyl radicals can partake in unwanted side rxns, causing cell damage
- Many cancers thought to be a result of reactions between free radicals and DNA, resulting in mutations that can affect the cell cycle and lead to malignancy
Cancer risk factors
How does the body minimise damage by free radicals
- As free radicals essential for life, body has mechanisms to minimise the cell damage done by them and to repair cell damgage that does occur
- The enzyme, superoxidase dismutase, minimises free radical induced cell damage and repairs some of the damage
- Antioxidants neutralise free radicals -> vitamins A, C, E are antioxidants
Cancer risk factors
Diet as a risk factor for cancer
- Fruit and veg (contain antioxidants) are protective against cancers
- Eastern diet containing many plant products contains many beneficial ingredients
- Western diet, opposite effect
- Mediterranean diet: good as high in fruit and veg, red wine (phenols), complex carbohydrates and low saturated fat content
Cancer risk factors
Diet - Fruit and Veg
- High fruit and veg consumption associated w decreased risk of many cancers
- High fruit and veg linked to low animal fat consumption
- Carotenoids, found in many plants, are: rich in antioxidants, precursors of Vit A which hinders cellular proliferation
- Plant derived vitamins, A,C,E have antioxidant properties
