A new avenue of treatment could fight two of the most prominent cancers — effectively hitting both leukemia and breast cancer. We could soon be inhibiting tumor growth by targeting a single protein, and this could revolutionize treatments of both diseases. Two papers published this week in the Journal of Experimental Medicine examine the protein HSP90, which plays a role in the growth of tumors.

Top image: Breast cancer cells by Annie Cavanagh/Wellcome Images

Certain types of leukemia have proved difficult to combat — they involve a hyperactive version of the enzyme JAK2, but at the same time are resistent to JAK2-blocking drugs. So an approach that targets HSP90 could have way more success. In these studies, researchers discovered that inhibiting HSP90 slowed the growth of resistent leukemia in mice, and would potentially work in humans too. The HSP90 inhibitors are 100–1,000-fold more potent than drugs which target the mutant version of JAK2.


With breast cancer, the target is migration inhibitory factor (MIF) which, when present in high quantities, means aggressive tumor growth and a poor prognosis. The MIF is protected by HSP90, so when you inhibit the latter, the former loses much of its power. In tumors with MIF, HSP90-inhibition markedly slowed their growth, though it had little effect on those without the factor.

Both of these methods target the same protective protein, and both could slow tumor progression — in certain cases. Hopefully with more research, we'll be able to expand this avenue of treatment to other tumor types too.