Recent advances in diagnosis, molecular pathology and therapy of chronic myelomonocytic leukaemia

The clinical, morphological, and genetic heterogeneity of chronic myelomonocytic leukaemia (CMML), has made it difficult to clearly assign this entity to a distinct haematological category. In 2001, the World Health Organization transferred CMML to a new category of mixed myeloproliferative/myelodysplastic disorders, which was maintained in the last revision in 2008. Considering the rare occurrence of CMML, most pharmacotherapeutic and transplant studies combined CMML with myelodysplastic syndrome cases, but some clinical trials specifically investigated the use of demethylating agents in CMML and demonstrated stabilization of the haematological situation or even complete remission in subsets of patients. Information on the significance of other drugs is very limited. Allogeneic haematopoietic stem cell transplantation (HSCT) remains the only curative option for patients with CMML. Molecular studies revealed various novel genetic alterations in CMML - notably of the JAK2, TET2, CBL, IDH, or RUNX1 and RAS genes. This review summarizes the current status of pharmacotherapy and transplantation in CMML and outlines recent results of molecular research for diagnosis of this heterogeneous entity.