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CR&T awards grant to Johns Hopkins group for studies of polycythemia vera

About 50 years ago the eminent hematologist William Dameshek coined the term "myeloproliferative disorders" for four diseases originating in the bone marrow in which a mutation in a single stem cell leads to rampant overproduction of one or more types of blood cells.

Diagnosed collectively in over 20,000 Americans a year, these four disorders are chronic myeloid leukemia, polycythemia vera, essential thrombocytosis, and agnogenic myeloid metaplasia.

The first two have lately yielded exciting treatment news, as the new drug Gleevec has proved highly effective against CML and has shown preliminary signs of effectiveness against PV.

Another cause for excitement is recent progress in identifying molecular defects of blood cells in PV, a disease that has intrigued medical scientists going back to Johns Hopkins' legendary chief of medicine William Osler a century ago. Much studied though it has been, PV can be difficult to diagnose, let alone treat, even today.

Now CR&T has awarded a grant to a group at Johns Hopkins that has identified abnormalities on the surface of stem cells that appear to be associated specifically with PV.

The Johns Hopkins group has found a paucity of receptor proteins called Mpl on the surface of stem cells from PV patients. They also have found Mpl receptors from PV patients to have an abnormal structure. In addition, when this aberrant form of Mpl turns up in another myeloproliferative disease, essential thrombocytosis, that condition tends to develop into PV.

The Hopkins group, led by Dr. Jerry L. Spivak, a professor of medicine and oncology, will use the grant from CR&T to pursue these observations in mice. In some experiments they will use specially bred mice whose cells lack the receptor protein entirely. They will inject these mice with a virus carrying a gene that makes the abnormal receptor, so that they can monitor the receptorís precise effect on the mice.

In other experiments they will transfer stem cells from PV patients to special mice that lack the capacity to reject transplanted cells from humans. The scientists will then observe the effect of the stem cells as they become established in the mice.

Says Spivak, whose earlier work on the Mpl-PV connection has appeared in such leading journals as The New England Journal of Medicine: ìWeíre tremendously grateful to CR&T for supporting these studies. Ultimately, we hope, they will lead to breakthroughs in understanding the causes of PV and in suggesting drug-development strategies for this very difficult disease.î

For additional information, please contact:
Cancer Research & Treatment Fund
Phone: 212-288-6604
Fax: 212-288-7704 or 212-746-8246
e-mail: director@crt.org