Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Clinical and Chemical Pathology

Back ground Philadelphia chromosome{u2013}negative myeloproliferative neoplasms constitute a heterogeneous group of hematopoietic disorders manifested by a variety of morphologic changes in the bone marrow (BM).Calreticulin(CALR) is a multifunctional protein that binds Ca2+ions (a second messenger in signal transduction), rendering it inactive.The Ca2+ is bound with low affinity, but high capacity, and can be released on a signal.CALR is located in storage compartments associated with the endoplasmic reticulum. Aim of the work: The aim of this study is to describe and correlate the morphologic features ofmyeloproliferative neoplasms(MPNs) especially ET and PMF with CALR mutations. Patients and Methods: The study was conducted on 68 MPNs patients;41/68 ET ,24/68 PMF and 3/68 post ET-MF.CALR Mutations By High ReslutionMelting(HRM) Analysis and Bone marrow trephine biopsy were done. Results : CALR-mut ET patients were more likely to show dense clustering of megakaryocytes compared to CALR-wt patients 8/10 (80%) vs 13/31 (41.9%) (p = 0.036).CALR-mut PMF showed megakaryocytes that more often exhibited nuclear hyperchromasia compared to CALR-wt PMF 3 / 4(75%) cases vs 11 / 20(55%) cases ( P = .0615). All post ET-MF patients showed variable megakaryocyte morphology. 3/4(75%) were JAK 2 positive .variable morphology included more abnormal bizzare ,hypolobated morphology

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