In peripheral blood samples. That's important because they show that some of the epigenome changes are concentrated in specific biochemical pathways related to

In peripheral blood samples. That's important because they show that some of the epigenome changes are concentrated in specific biochemical pathways related to cancer. But, they don't find pathways specific to blood cancers, so I'm really not sure what to make of that. What does it mean that a white blood cell has epigenomic changes similar to those observed in a collection of other studies of colorectal cancer? Honestly, probably not a lot. I'm made even less certain by the finding that the epigenomic changes are strongly concentrated in pathways like "Bacterial infection of epithelial cells". That's quite obviously statistical noise, but there's not much you can do about that when you're doing these population scale biochemical/genetic studies. They also report that the cannabis smoking group had a statistically significant difference in cigarette smoking, so that's probably a big confounder, along with other lifestyle choices that you might expect between people who report never smoking weed vs those who do. It's just really really hard to make strong conclusions from a single study like this.