Acquired DNA mutations associated with in vivo hydroxyurea exposure

Occurrence of acute myeloid leukemia in hydroxyurea-treated sickle cell disease patient

Hydroxyurea (HU) has been widely used in sickle cell disease. Its potential long-term risk for carcinogenesis or leukemogenic risk remains undefined. Here, we report a 26 y old African-American female with Sickle Cell Disease (SCD) who developed refractory/relapsed acute myeloid leukemia (AML) 6 months after 26 months of HU use. That patient's cytogenetics and molecular genetics analyses demonstrated a complex mutation profile with 5q deletion, trisomy 8, and P53 deletion (deletion of 17p13.1). P53 gene sequence studies revealed a multitude of somatic mutations that most suggest a treatment-related etiology. The above-mentioned data indicates that the patient may have developed acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) as a direct result of HU exposure.

Platelets and Thrombosis in Myeloproliferative Diseases

The myeloproliferative disorders have been the “poor cousins” in the family of hematological malignancies for some time. Recently this field has advanced considerably with the description of a mutation in the JAK2 kinase detectable in the majority of patients and the publication of two landmark clinical trials—ECLAP and MRC PT1. But although both ECLAP and MRC PT1 inform clinical management and allude to the complexities of thrombosis we still lack fundamental knowledge, and our understanding of thrombosis in these conditions has not paralleled advances in the field of thrombosis and vascular biology. The predominant clinical complications of essential thrombocythemia and polycythemia vera are thrombotic and hemorrhagic; these significantly impact upon prognosis and quality of life. Here the current status of our knowledge is reviewed with specific emphasis upon the role of the platelet in the pathogenesis of thrombosis as well as the impact of recent data from ECLAP and MRC PT1.