“The pharma companies already have a cure for cancer, they just wont tell anyone because they wouldn’t make any money.”
The myth that Big Pharma has already cured cancer, and just isn’t telling us, has been going around for many years. It’s something I often get asked about when I tell people what I do. Unfortunately, the reality is that we are a very long way off curing cancer.
It isn’t one disease
The problem is that cancer isn’t one disease, it’s hundreds. Every single type of cell that makes up your body is capable of becoming cancerous. That’s 200 different types of cancer. And this is where the problem starts; because there are so many types of cancer, they all need treating in different ways. Even in cancers that originate from the same cell types, there can still be huge variation between what that cancer will respond to in different people. How a cancer cell will react to different drugs depends on why it started growing uncontrolably in the first place.
Doesn’t chemotherapy target all cancers?
The word ‘chemotherapy’ is actually a broader name for a whole class of drugs that are cytotoxic. Meaning, they are toxic to all cells.Chemotherapy drugs work by stopping all fast growing cells in the body, including the cells that are supposed to grow and divide faster than others.
When somebody is treated with chemotherapy, it means that their hair follicles and blood cells are also massively affected because they can’t divide like they normally do, which is why many people on chemotherapy have hair loss and are prone to infections and anaemia. When they first came out, the hope was that chemotherapy would cure cancer. However, the reality has been a bit different.
Sort of, but they can (and do) escape.
Cancer cells are very prone to picking up more mutations when they divide, because one of their hallmarks is that they’ve evaded all of the normal checkpoints in a cell that would stop them dividing if everything wasn’t quite right. Lots of these checkpoints are to check that the DNA in the cell has been copied completely and accurately. When these aren’t in place, the replication machinery becomes very sloppy and makes even more mistakes than normal. What’s worse is that these mistakes aren’t noticed and corrected like they would normally be. Due to this, cancer cells can pick up mutations that mean they escape the drugs used for chemotherapy and continue to grow.
What about treatments that specifically target the different cancers?
A lot of the recent work in drug discovery has been to target specific things in the cancer cells that are driving their growth. Scientists have had a lot of success with targeting some proteins, and more targeted drugs are becoming available, which is great news! Most of these targeted therapies work against tyrosine kinases, or hormone receptors. Some of the more ‘famous’ ones are imatinib and tamoxifen, that work against BCR-Abl tyrosine kinase in CML and the oestrogen receptor in certain breast cancers, respectively.
They can get around those too.
In a normal cell, tyrosine kinases act like a switch to send signals from the outside of the cell to the inside, turning off when their message has been relayed to the next molecule in the pathway. In cancer cells, these switches are stuck in the ‘on’ position, meaning that they keep sending their signal to the rest of the cell. When drugs target these switches, they shut them down and cut off the pathway that the cell has become addicted to. The mutations that we mentioned earlier can also mean the cells quickly develop other ways to grow that don’t rely on their original driver pathways.
These cancers are quite sneaky, can we ever beat them?
Every time scientists design a new drug, or find a new target, it seems the cancer finds a way to work around it. But people are currently being cured of cancer. The relapse-free survival rates 10 years post-diagnosis are higher now for most cancers than ever before. By combining lots of different types of drugs together, we give the cancer less of a chance to find an escape route. If, for example, we can use chemotherapy together with a targeted treatment and surgery to remove the cancer on top of that, we stand a much better chance of getting rid of it for good.
We’re getting there!
Unfortunately, not every cancer has a targeted therapy that will work for it. Sometimes the cancer can already be advanced at diagnosis, spreading into the surrounding tissues and other organs away from where it began. The prognosis isn’t as good for these cases yet, but we are working on it. If there was one drug to rule them all, we would definitely be using it already.