From what the article says, at least it seems like chemotherapy is pretty effective against these cancers, which is a good thing. It's certainly better than having brain cancer, which usually doesn't respond to chemo very well. It's because the chemo can't get through the blood-brain barrier very well. I know that from a friend whose wife died from a glioma, which is some kind of brain cancer. You find out these kinds of facts when your life is spent in doctors' offices.
I think I've read that chemotherapy is generally effective against most blood cancers, unless there's a mutation they find that makes the cancer harder to treat. I wonder why it works so well with some cancers and not much against others.