title: Acute Lymphoblastic Leukemia Arising in CALR Mutated Essential Thrombocythemia.
abstract: The development of acute lymphoblastic leukemia in an existing myeloproliferative neoplasm is rare with historical cases unable to differentiate between concomitant malignancies or leukemic transformation. Molecular studies of coexisting JAK2 V617F-positive myeloproliferative neoplasms and mature B cell malignancies indicate distinct disease entities arising in myeloid and lymphoid committed hematopoietic progenitor cells, respectively. Mutations of CALR in essential thrombocythemia appear to be associated with a distinct phenotype and a lower risk of thrombosis yet their impact on disease progression is less well defined. The as yet undescribed scenario of pro-B cell acute lymphoblastic leukemia arising in CALR mutated essential thrombocythemia is presented. Intensive treatment for the leukemia allowed for expansion of the original CALR mutated clone. Whether CALR mutations in myeloproliferative neoplasms predispose to the acquisition of additional malignancies, particularly lymphoproliferative disorders, is not yet known.
authors.affiliation: Cancer Molecular Diagnostics, St. James's Hospital, Dublin 8, Ireland.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Langabeer
authors.affiliation: Cancer Molecular Diagnostics, St. James's Hospital, Dublin 8, Ireland.
authors.forename: Karl
authors.initials: K
authors.lastname: Haslam
authors.affiliation: Department of Haematology, St. James's Hospital, Dublin 8, Ireland.
authors.forename: David
authors.initials: D
authors.lastname: O'Brien
authors.affiliation: Department of Clinical Genetics, Our Lady's Children's Hospital, Dublin 12, Ireland.
authors.forename: Johanna
authors.initials: J
authors.lastname: Kelly
authors.affiliation: Department of Haematology, St. James's Hospital, Dublin 8, Ireland.
authors.forename: Claire
authors.initials: C
authors.lastname: Andrews
authors.affiliation: Department of Histopathology, St. James's Hospital, Dublin 8, Ireland.
authors.forename: Ciara
authors.initials: C
authors.lastname: Ryan
authors.affiliation: Department of Histopathology, St. James's Hospital, Dublin 8, Ireland.
authors.forename: Richard
authors.initials: R
authors.lastname: Flavin
authors.affiliation: Department of Haematology, St. James's Hospital, Dublin 8, Ireland.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Hayden
authors.affiliation: Department of Haematology, St. James's Hospital, Dublin 8, Ireland.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Bacon