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Andreas Giannopoulos
Niki Rougkala
Theodoros Loupis
Marina Mantzourani
Nora-Athina Viniou
Eleni Variami
Theodoros Vassilakopoulos
George Dryllis
Ioannis Kotsianidis
Theodora Gougopoulou
Marianna Politou
Konstantinos Konstantopoulos
George Vassilopoulos *
(*) Corresponding Author:
George Vassilopoulos |


Background and Objectives

Somatic mutations in the calreticulin gene (CALR) are detected in approximately 70% of patients with essential thrombocythemia (ET) and primary or secondary myelofibosis (MF), lacking the JAK2and MPLmutations. To determine the prevalence of CALRframeshift mutations in a population of MPN patients of Greek origin, we developed a rapid low-budget PCR-based assay and screened samples from 5 tertiary Haematology units. This is a first of its kind report of the Greek patient population that also disclosed novel CALRmutants.



MPN patient samples were collected from different clinical units and screened for JAK2and MPLmutations after informed consent was obtained. Negative samples were analyzed for the presence of CALRmutations. To this end, we developed a modified post Real Time PCR High Resolution Melting Curve analysis (HRM-A) protocol. Samples were subsequently confirmed by Sanger sequencing.



Using this protocol we screened 173 MPN, JAK2and MPLmutation negative, patients of Greek origin, of whom 117 (67.63%) displayed a CALRexon 9 mutation. More specifically, mutations were detected in 90 out of 130 (69.23%) essential thrombocythaemia cases (ET), in 18 out of 33 (54.55%) primary myelofibrosis patients (pMF) and in 9 out of 10 (90%) cases of myelofibrosis secondary to ET (post-ET sMF). False positive results were not detected. The limit of detection (LoD) of our protocol was 2%. Furthermore, our study reavealed 6 rare novel mutations which are to be added in the COSMIC database. 



Overall, our method could rapidly and cost-effectively detect the mutation status in a representative cohort of Greek patients; the mutation make-up in our group was not different from what has been published for other national groups.

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