Why don't all cases of MDS turn into AML?

Why don't all cases of MDS turn into AML? It depends on what's going on in the bone marrow and the stem cells. So if they have high risk cytogenetics that I described, most of the times they do progress. It's only a matter of time. As I said, MDS is in the older patients and they may have other competing medical problems going on. So high risk MDS most of the times progresses. We don't know when, but most of the times they do. Low risk is, we're still learning more about what causes the progression versus not. Some patients, even if it is low risk, can progress faster versus... That's why we need more research into this area.