I guess there could be many genes that affect the “grow uncontrollably” part or the “refuse to die” part, but can’t we just target all of them?
In: Biology
There’s a number of challenges with that. First, you have to identify what gene has the harmful mutation. This is already super difficult – people have been researching this for decades and we’re still very far from mapping every possible gene mutation that can cause cancer. It’s also worth noting that it normally takes a number of mutations across several genes in order for a cell to become cancerous, so that raises the question of which one to target (or else you’d have to target all of them, making your job that much harder). Usually earlier mutations switch off the cell’s own safety protocols that are supposed to defend against cancer, while later ones actually cause the cancerous behavior, but so it’s not as easy as just comparing a cancer cell to a healthy one and finding the places in the DNA that are different.
Second, you have to find a way to program CRISPR to reliably target the bad genes and not other genes that happen to be similar. This may take a lot of trial and error (using tissue samples from the patient), if it is even possible on a patient-by-patient basis. Get it wrong, and you may end up damaging other genes and thus causing side effects that could be severe.
Third, you then have to be able to replace the mutated sequence with a healthy alternative, which is another thing you have to get right based on the individual patient’s genome.
Fourth, you have to be able to deliver your treatment to every cancer cell (or at least to enough of them that the patient can go into remission for a long time before needing treatment again). This is also really difficult. You either need a way to target cancer cells specifically (which, if you have that, that in itself would be a much more direct route for treatment), or you need to be able to target every cell within the area that is known to be affected, e.g. entire organs or bodily systems.
There are gene-editing based cancer treatments being researched, but they tend to have a different approach: programming some of your own immune cells to target the cancer.
In general, trying to turn cancer cells back into healthy cells is kind of overkill. In the vast majority of cases, you can survive losing each and every one of those cells. So why not just destroy them? In fact, not only can you typically live without the affected cells, but often their very presence is a problem, because they are taking up space and using up resources in places where they aren’t needed. You’re not going to be healthier after turning a colon tumor back into a big lump of “normal” colon cells, because it’s not healthy to have a lump in your colon to begin with.
Latest Answers