What happens to blood cells w... Video Transcript

Participants

, Michael Mauro MD, Gwen L. Nichols MD

Summary

Doctors understand what goes wrong in CML more than they do in most other cancers. Learn what happens in the genes of white blood cells to cause CML.

Webcast Transcript

So what goes wrong in patients who have CML in their blood? It really starts in the bone marrow. If someone were to be caught very early in their CML, we might not even see changes in the blood. So what happens is one of the early cells, or the stem cells, we think, undergoes damage, a genetic alteration known as the Philadelphia chromosome. It's a genetic translocation or swapping of genetic material. And that cell then becomes immortalized. It's not regulated any longer, and the specific event that is related to the Philadelphia chromosome essentially is like a light switch. It turns the cell on, and that cell no longer behaves normally. It grows and divides somewhat faster.

One of the main reasons that it's abnormal is it doesn't know when to die or senesce, so those cells start to build up in the marrow. And it's generally thought to be at a stem cell level, but it mainly affects the white blood cell and the platelet lineage, and that's why when someone is facing CML, those are the features we usually see, an elevated white count and an elevated platelet count.

So that starts first in the bone marrow, and those cells build up. So the bone marrow is overstuffed with blood, or hypercellular, as we call it. The blood then shows spillover, and that's why the white blood cell count and the platelet count are elevated.

The reason why we see cells that are quote-unquote &immature,& even cells to the most immature stage or blast stage in the blood is that those cells are normally in the marrow, and they're essentially being pushed out as the marrow is overfilled.