Question: why do people get cancer? can it run in the family?

Jessica Chu answered on 15 Jun 2011:

Great questions!!

Question 1.
There a lots of answers to why do people get cancer and many of the possible answers are still being proved by doing more research.
There are many causes – the genes you get from you family, lifestyle (diet, smoking and alcohol (are both very bad for cancer) ), exposure to radiation without protection e.g. playing for hours in the sun without sun cream. Here is a list of things of what goes wrong inside a normal cell that causes it to become a cancer cell.

Some of the main reasons described by D. Hanahan and R.A. Weinberg about why cells become cancerous is because:
1. the cell’s growth signals have gone out of control
The cancer cells are able to make their own growth factors (proteins that send signals to the cell to divide and grow) rather than relying growth factors made from other cells. Or the cells have mutations in the genes that will allow it to keep growing!

2. Not responding to growth stopping signals
Normal cells can stop growing when they receive signals from outside the cell tells them to stop. However, cancer cells do not listen to these signals and do quite the opposite, which is to keep growing indefinitely!!! rebellious cells!!

3. Fighting cell death signals
Usually, a damaged normal cell will try to fix itself unless the damage is so great that it is impossible to do so then the cell will receive signals to undergo apoptosis (a fancy word but it basically mean cell death). It is normally damage in the DNA (genetic codes).
Cancer cells will not listen to these cell death signals and keep growing with the damaged DNA.

4. Unlimited potential to divide
Remember I mentioned those things called Telomeres at the end of chromosomes in cell ageing. Well they have a big role in cancer cells too! Normal cells will stop dividing after they have reached their own Hayflick limit (number of cell division) because telomeres get shorter and shorter after each round of DNA replication until no more telomeres are protecting the chromosome anymore then it will die. Cancer cells can produce its own telomere making enzymes (telomerase) and tell them to keep adding telomeres on to the end of chromosomes after each DNA replication so the cell never have to die!!

People in my lab are making drugs to target the enzyme, telomerase!

5. Making new blood vessels
Like normal cells, cancer cells need food and oxygen delivered to them via the blood vessels in order to keep growing.
But unlike normal cells, cancer cells can send signals in its surrounding to stimulate the growth of new blood vessels so they can have food delivered straight to them!! (So like when you order a pizza from dominos- they will deliver the pizza and garlic bread straight to your door!!)

6. Moving around the body
Most normal cells will stay in one place in the body until they die and again, cancer cells love doing what they are not supposed to!
So cancer cells have their own mutated enzymes (imagine the enzymes are like a pair of scissors, they are able to cut around the cancer cells from neighboring cells so they are free to move around).
As I mentioned in point 5, the cancer cells already have their own blood vessels so these cancer cells that are free to move around can travel in the blood vessels to pretty much anywhere else in the body and live there (almost like an enormous water slide!!)
At this late stage, this is when the cancer cells are at its most dangerous and can kill people ):

Question 2.
Yes certain types of cancers run in the family. For example if someone in your family have got breast cancer than you are more likely to get it too thats why doctors like to get everyone (when they are older 25+ years old) in the clinic or hospital to do some testing just incase!
An example is one type of eye cancer that affect 1 in 20, 000 children. The genes (short lengths of DNA that codes for certain proteins) they get from their parents are responsible for this cancer growth.

I hope this helps! If I didn’t explain it well- feel free to tell me and I will try again

Jess