College aantekeningen
College aantekeningen Nutrition and Cancer (HNH-37806)
Dit document bevat een uitgebreide samenvatting van het vak Nutrition And Cancer (HNH-37806).
[Meer zien]Voorbeeld 3 van de 88 pagina's
Voorbeeld 3 van de 88 pagina's
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Voorbeeld van de inhoud
Nutrition and CancerIntroduction to Nutrition & Cancer
Global cancer incidence
- 18.1 million new patients per year in the world (2018)
- Major cancers worldwide, new cases per year (%)
o 1. Lung 2.1 million (11.6)
o 2. Breast cancer 2.1 million (11.6)
o 3. Colorectum 1.8 million (10.2)
o 4. Prostate 1.3 million (7.1)
Cancer is one of the most frequent and lethal diseases in the world
- It affects many people
- For some types of cancer, cures are still far away
- It is going to affect more and more
- We need to know more about cancer etiology & progression and the role of diet
- We need evidence-based dietary guidelines for cancer prevention
- We need more diet & cancer researchers from various disciplines
Keep in mind: coverage of cancer registries
Cancer registries cover the majority of populations in developed regions, but almost none in emerging economies.
Cancer mortality
- 9.6 million cancer-related deaths (2018)
- Most cancer-related deaths for lung, colorectal, stomach and liver cancer
- Pancreatic cancer has a high mortality rate
Global cancer incidence and mortality: men
- Top 3: lung, prostate and colorectum
- Lung cancer is very difficult to treat (incidence and mortality is high)
- Prostate cancer has a high incidence but a low mortality, this cancer can probably be treated well
Global cancer incidence and mortality: women
- Top 3: breast, colorectum and lung
- Breast cancer has a high incidence but a lower mortality, so the treatment is probably okay
Projected cancer incidence and mortality burden from 2018 to 2040
- Incidence
o 2018: 18 million
o 2040: 29.5 million
- Mortality
o 2018: 9.6 million
o 2040: 16.5 million
- This increase is because of the world population is increasing and people become older
o Age is one of the biggest risk factors for cancer
Cancer 5 year prevalence
- 43.8 million people (above age 15) alive who had cancer diagnosed in the previous 5 years
o Most of the time: breast, colorectal and prostate
1
,Genes play a role in cancer development
~5-10% of all cancers is hereditary, for example breast cancer can be a mutation in a gen
Incidence differs between different countries
- Global incidence of colorectal cancer
o It happens a lot in Europe, north America and Australia
- Global incidence of stomach cancer
o It happens a lot in Asia and south America
Japanese migrants in Hawaii
- The incidence changes in the next generation
- It is probably the environment and dietary habits that cause this effect
Environment plays a role in cancer development
- Smoking, radiation, chemicals, viruses, sun bathing, hormones
Hallmarks of cancer
Cancer....
- Is not one disease
- Is a multistep process
- Start with single cell
- Multiple cell types involved
Accumulation of (epi)genetic changes
It all starts with this one, normal cell and as a consequence of
(epi)genetic changes, the genetic make-up of this cell might be
changed. The affected cell will continue to divide and the
daughter cells might also get this mutation. This process
continues and ends up in a population of cells that have a
different genetic make-up. At a certain moment, some essential
tasks within the cell do not function properly anymore and this
may contribute to the development of cancer.
To conclude
- Tumorigenesis is a multi-step process
- Multiple (epi)genetic alterations are required
- Development over many years
- Cancer cells less responsive to regulatory circuits of cellular proliferation and cell death
2
, Hallmarks = acquired functional capabilities that allow
cancer cells to survive, proliferate (grow) and disseminate
(spread).
The enabling characteristics (genome instability and
mutation, and tumour-promoting inflammation) are
characteristics that contribute to the other hallmarks, but
they might not be specific for cancer cells. They can also
be seen in other processes. The emerging hallmarks
(deregulating cellular energetics, and avoiding immune
destruction) are hallmarks that are probably also core
characteristics of cancer cells, but the evidence is still
emerging and the mechanisms are not fully established
yet.
Hallmarks: Growth and survival
Hallmarks directly related to growth and survival of the cancer cells
- Sustaining proliferative signalling
- Evading growth suppressors
- Resisting cell death
- Enabling replicative immortality
Cancer cells: growth
Cell cycle
The cell cycle is responsible for cell division, meaning that one mother cell
divides in two daughter cells. Usually the cell cycle starts in the G1 phase,
which is the preparation phase. Next, cells enter the S (synthesis) phase in
which the DNA is actually copied (RNA replication). G2 is another
preparation phase for the M (mitosis) phase in which the cells are divided
into two new cells. Between the different phases are so-called restriction
points to check whether the cell still functions properly. If everything is okay, the cell cycle can continue.
- Proliferation = growth
o physical growth (cells become larger) or an increasing number of cells
- Differentiation = specialisation
o E.g., a stem cell that becomes a specialized cell with a particular function in the liver
- Replication = coping of the DNA in the S phase of the cell cycle
Now, the core hallmarks sustaining proliferative signalling and evading growth suppressors are discussed.
Sustaining proliferative signalling (=chronic proliferation)
- For chronic proliferation, growth factors play a very important role
o A growth factor can bind to a growth factor receptor which is usually present in the cell
membrane
o After binding of the growth factor to the receptor, specific processes can take place. For example,
phosphorylation (= when a phosphate group is added to the receptor which leads to a change in
the structure of the receptor). E.g., two receptors come together and form a dimer, then a signal
is sent to the nucleus which indicates that proliferation should be started.
- Cancer cells use growth factors to promote proliferation.
o Increases the synthesis of growth factors by tumour cells
o Increases the synthesis of growth factors by neighbouring cells
o Increases the production of receptors at cell surface → can also lead to proliferation
o structural alterations receptors → increased response
o activation downstream pathway
3
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