Question: What do cancer ingections do to protect you from it?

Ee Lyn Lim answered on 23 Jun 2013:

There are many kinds of medicines that can be used in cancer injections! The ones we commonly use contain drugs that stop cells from dividing. These are supposed to harm cancer cells more than your normal healthy cells, because cancer cells are growing out of control. The drugs work in many ways – for example there are some that stick your DNA together so that they can’t be copied properly when a cell divides, or there are others that stop a cell changing shape so that it can’t split into two. Interestingly, for some of these chemotherapeutic agents we don’t even know exactly how they work! (just that they stop cells diving – but not how.) This isn’t good news, because that means that if they also affect our healthy cells (like hair follicles, as Peter said, or more seriously our immune cells!) then we don’t know how to stop it.

So scientists are now doing research to make new drugs that are a bit more specific! Cancer cells have some special features that allow them to grow really fast, but also make them a bit unstable – if we can target those, then we can kill them a lot faster, before we start hurting the healthy cells too. For example, cells usually have a few ways to repair themselves when they get damaged, but the bad news is that if they get TOO damaged then the same mechanisms will just kill them. Cancer cells don’t want that – they want to be repaired, but they don’t want to be killed! So they shut down all the mechanisms except the most basic ones, which allow them to keep growing no matter how damaged they are. What we can do now is: inject a drug that shuts down those basic mechanisms too, so that now the cancer cells have no way to repair themselves at all – so they quickly get so damaged that they can’t continue growing! The healthy cells are alright because they haven’t shut down their other repair pathways, so it’s only the cancer cells that will suffer. If we combine this kind of drug with the old kind, which damages cells, then we can get a very powerful combination attack that kills off cancer cells!

But we’re researching new types of medicines all the time, so that we can avoid having to hurt the normal cells at all, and just get rid of the cancer cells. One of the ways is to help your immune system do the job itself! My project is trying to invent a drug that will give your immune system a boost, so that they can go hunt down the cancer cells and kill them – it isn’t harmful to your normal cells at all. So what goes into the injections is changing – and hopefully getting better – all the time!