Professor Luke O'Neill

An increased risk of colorectal cancer in that case.

Another one, bacteroides fragilis, that was shown again to increase the risk of colorectal cancer.

And one reason for that is that type of bacteria makes a nasty toxin, because many bacteria make toxins, that will disrupt the epithelium, which is in the gut.

That's the name of the barrier in the gut.

causing real irritation and increasing the risk of colorectal cancer.

And then one last example that I like, because it's relevant to my own research, a bacteria called Enterococcus faecalis.

That will irritate the gut hugely and damage the DNA.

And most cancers are actually caused by a mutation in the DNA.

And the gene changes and you give rise to the overexpression of a nasty broken protein that promotes cancer development.

So all that's been kicking around for a while, that those bacteria increase risk.

Now, of course, people have tried then to clear these bacteria in various ways.

You can't selectively take out one species.

You can use antibiotics, of course, but the trouble is they come with other problems.

they can increase sort of all kinds of issues, really.

Overuse of antibiotics wouldn't be the best thing necessarily.

So even though we know some of these bacteria are a risk factor, you can take antibiotics to clear helicobacter, and that will indeed decrease your risk of gastric cancer, which is a good thing.

But it's a very active area.

Can we limit these bacteria to protect against cancer?

Now, the second area, though, is this.

Can the bacteria in your gut predict responsiveness to therapies we have already used?