We all know that cancer is bad. But what exactly is ‘cancer’? Cancer is a word we use to describe abnormal changes that happen in healthy body cells. Our body is made up of trillions of cells and they all work together to keep our body running efficiently. So, what happens? Why are cancer cells different to our normal healthy cells? If you’re curious, read on to find out more! We’re going to go through the seven ways that cancer cells are different and what they mean.
1. Shape of the cells
Normally, healthy cells look the same as each other. Cancer cells, however, look different to healthy cells and also different to each other. They are often strangely shaped and their edges are not clear, unlike in healthy cells where it is easy to see where one cell ends and the next begins. Another difference is in the size of the cell’s nucleus. Almost all healthy cells have one nucleus, which is the cell’s control centre and holds its DNA. Cancer cells can have more than one nucleus, and they are often much larger and take up too much space in the cell.
Can you see the difference between these pictures of real cells? From these microscope slides you can see how variable cancer cells are compared to healthy cells.
2. Damaged genetic code
In a cell’s nucleus, you will find your unique genetic code in the form of DNA. In healthy cells, the DNA is wound up tightly into 46 chromosomes. Cancer cells have faults in the number of chromosomes like having too many or too few which makes it more difficult for the cell to divide properly. In normal cell division, the chromosomes are lined up in a specific way to make sure each new cell has a correct copy of each chromosome. Having faulty chromosomes means that it’s harder to divide properly, so more problems happen each time as the cancer cell multiplies.
The contents of the nucleus are very different for cancer cells – they can have the wrong number of chromosomes and those that are present are often broken because of missing bits or bits added.
3. Abnormal DNA
Abnormal changes – called mutations - that happen in a cell’s DNA are what makes a cell become cancerous. Our DNA contains thousands of genes which work together to control everything from our hair colour to how many times each cell can duplicate itself.
These mutations to DNA can become dangerous when they mean that a cell can’t stop itself from duplicating, forming a tumour that grows out of control. Cancer cells can have many DNA mutations which collectively mean that they then do not follow the normal rules of the body.
The DNA that the chromosomes are made of have many errors in cancer cells. This can mean that cancer cells can duplicate themselves a lot faster than healthy cells, and gives them other abilities that healthy cells don’t have.
4. Won’t stop growing
One of the ‘rules’ that cancer cells ignore is called ‘programmed cell death’. Normally, when a cell is broken or is no longer needed, a process which kills the cell is activated. This process happens every day within our bodies without any problems. However, if a DNA mutation has broken the genes responsible for making this process happen, then the cancer cell lives to divide another day.
Another ‘rule’ is that healthy cells should wait to receive a signal from nearby cells to tell them they need to divide, so that tissue (a group of similar cells) growth is carefully managed by our bodies. However, cancer cells can divide without ever receiving this signal and so can continuously keep replicating without any limits, forming a tumour.
Healthy cells are only allowed to divide a specific number of times, but cancer cells find ways to divide infinitely, forming tumours.
5. Hides from our immune system
Cancer cells can hide from our immune system. There are a few different ways they can do this, largely by using proteins on the cell’s surface. These proteins act like a unique fingerprint, telling other cells what type of cell it is (such as muscle cells, nerve cells and so on). When a cell becomes cancerous, the surface proteins can change due to its many DNA mutations. Whilst this change should tell our immune system to kill the cell, sometimes the proteins make the cancer look like a normal cell so that the immune system will ignore it. These proteins can also attract other cells that prevent the immune system from getting to the cancer cell. These are a couple of ways that cancer cells can continue to grow and multiply enough to become a tumour.
Cancer cells find ways to hide from the immune system which wants to destroy them. Our immune system uses proteins on the cell’s surface to identify broken or dangerous cells. Cancer cells sometimes disguise themselves with healthy protein markers that ma
6. Demands nutrients
Healthy cells can signal for blood vessels to grow nearer to them. They do this only during normal growth and development, to make sure the new cells are getting the resources they need from your blood. Cancer cells signal for blood vessels all of the time – even when they don’t need any extra resources to grow. These new blood vessels feed the tumour with nutrients that make it grow even faster.
Tumours attract a lot more blood vessels than normal tissue does. This allows tumours to grow even bigger as the blood vessels bring them nutrients.
7. Spreads elsewhere in the body
The other thing that the new blood vessels do is to provide easy access to the rest of the body. When cancer cells get into the blood stream, they can settle in a new location and become ‘metastatic’, meaning that the cancer has spread from the initial tumour to a secondary location. Normal cells don’t do this because the tiny proteins on their surfaces help keep them in their proper place but, because of the mutations, cancer cells can separate from the tumour and travel around the body.
Whilst healthy cells stick together, cancer cells don’t bond to their neighbouring cells because of the DNA mutations. This means that it’s easier for them to slip into the blood stream and spread around the body.
So, there you have it – seven reasons why cancer cells are different from healthy cells. Researchers try to use these differences to find new ways of targeting cancer cells without killing healthy tissue.
As there are so many types of cancers, and they are so variable, one treatment can’t help everyone. It is important that all children and young people have the best treatments for their cancer and so we will keep funding research into new and kinder treatments until there is a cure for every young person.
Ellie Ellicott is CCLG’s Research Communication Executive.
She is using her lifelong fascination with science to share the world of childhood cancer research with CCLG’s fantastic supporters. You can find Ellie on X: @EllieW_CCLG