Calreticulin mutation specific CAL2 immunohistochemistry accurately identifies rare calreticulin mutations in myeloproliferative neoplasms

Réka Mózes, Ambrus Gángó, Adrienn Sulák, Livia Vida, Lilla Reiniger, Botond Timár, T. Krenács, Hussain Alizadeh, T. Masszi, Júlia Gaál-Weisinger, J. Demeter, Judit Csomor, A. Matolcsy, Béla Kajtár, Csaba Bödör

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Abstract

Mutations of the multifunctional protein calreticulin (CALR) are recognised as one of the main driver alterations involved in the pathogenesis of Philadelphia negative myeloproliferative neoplasms (Ph MPN) and also represent a major diagnostic criterion in the most recent World Health Organization classification of myeloid neoplasms. Nowadays, quantitative assessment of the driver mutations is gaining importance, as recent studies demonstrated the clinical relevance of the mutation load reflecting the size of the mutant clone. Here, we performed for the first time a manual and automated quantitative assessment of the CALR mutation load at protein level using CAL2, a recently developed CALR mutation specific monoclonal antibody, on a cohort of 117 patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF) and compared the CALR protein mutation loads with the CALR mutation load values established by a molecular assay. Eighteen different CALR mutations were detected in the cohort of the 91 CALR mutant cases. Mutation loads of the CALR mutations were between 13% and 94% with mean value in PMF cases significantly higher than ET cases (49.94 vs 41.09; t-test, p=0.004). Cases without CALR mutation (n=26) showed no or only minimal labelling with the CAL2 antibody, while all 18 different types of CALR mutations were associated with CAL2 labelling. The CALR mutation load showed a significant correlation (p=0.03) with the occurrence of major thrombotic events, with higher mutation load in patients presenting with these complications. We report a 100% concordance between the mutation status determined by immunohistochemistry and the CALR molecular assay, and we extend the applicability of this approach to 16 rare CALR mutations previously not analysed at protein level.

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???journalAssociation???Pathology
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Calreticulin
Immunohistochemistry
Mutation
Neoplasms
Essential Thrombocythemia
Primary Myelofibrosis
Proteins

Keywords

    ASJC Scopus subject areas

    • Pathology and Forensic Medicine

    Cite this

    Calreticulin mutation specific CAL2 immunohistochemistry accurately identifies rare calreticulin mutations in myeloproliferative neoplasms. / Mózes, Réka; Gángó, Ambrus; Sulák, Adrienn; Vida, Livia; Reiniger, Lilla; Timár, Botond; Krenács, T.; Alizadeh, Hussain; Masszi, T.; Gaál-Weisinger, Júlia; Demeter, J.; Csomor, Judit; Matolcsy, A.; Kajtár, Béla; Bödör, Csaba.

    ???in???: Pathology, 01.01.2019.

    ???family-name???: Article

    Mózes, Réka ; Gángó, Ambrus ; Sulák, Adrienn ; Vida, Livia ; Reiniger, Lilla ; Timár, Botond ; Krenács, T. ; Alizadeh, Hussain ; Masszi, T. ; Gaál-Weisinger, Júlia ; Demeter, J. ; Csomor, Judit ; Matolcsy, A. ; Kajtár, Béla ; Bödör, Csaba. / Calreticulin mutation specific CAL2 immunohistochemistry accurately identifies rare calreticulin mutations in myeloproliferative neoplasms. ???in???: Pathology. 2019.
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    title = "Calreticulin mutation specific CAL2 immunohistochemistry accurately identifies rare calreticulin mutations in myeloproliferative neoplasms",
    abstract = "Mutations of the multifunctional protein calreticulin (CALR) are recognised as one of the main driver alterations involved in the pathogenesis of Philadelphia negative myeloproliferative neoplasms (Ph– MPN) and also represent a major diagnostic criterion in the most recent World Health Organization classification of myeloid neoplasms. Nowadays, quantitative assessment of the driver mutations is gaining importance, as recent studies demonstrated the clinical relevance of the mutation load reflecting the size of the mutant clone. Here, we performed for the first time a manual and automated quantitative assessment of the CALR mutation load at protein level using CAL2, a recently developed CALR mutation specific monoclonal antibody, on a cohort of 117 patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF) and compared the CALR protein mutation loads with the CALR mutation load values established by a molecular assay. Eighteen different CALR mutations were detected in the cohort of the 91 CALR mutant cases. Mutation loads of the CALR mutations were between 13{\%} and 94{\%} with mean value in PMF cases significantly higher than ET cases (49.94 vs 41.09; t-test, p=0.004). Cases without CALR mutation (n=26) showed no or only minimal labelling with the CAL2 antibody, while all 18 different types of CALR mutations were associated with CAL2 labelling. The CALR mutation load showed a significant correlation (p=0.03) with the occurrence of major thrombotic events, with higher mutation load in patients presenting with these complications. We report a 100{\%} concordance between the mutation status determined by immunohistochemistry and the CALR molecular assay, and we extend the applicability of this approach to 16 rare CALR mutations previously not analysed at protein level.",
    keywords = "CAL2 immunohistochemistry, calreticulin mutation, mutation load, Myeloproliferative neoplasms",
    author = "R{\'e}ka M{\'o}zes and Ambrus G{\'a}ng{\'o} and Adrienn Sul{\'a}k and Livia Vida and Lilla Reiniger and Botond Tim{\'a}r and T. Kren{\'a}cs and Hussain Alizadeh and T. Masszi and J{\'u}lia Ga{\'a}l-Weisinger and J. Demeter and Judit Csomor and A. Matolcsy and B{\'e}la Kajt{\'a}r and Csaba B{\"o}d{\"o}r",
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    T1 - Calreticulin mutation specific CAL2 immunohistochemistry accurately identifies rare calreticulin mutations in myeloproliferative neoplasms

    AU - Mózes, Réka

    AU - Gángó, Ambrus

    AU - Sulák, Adrienn

    AU - Vida, Livia

    AU - Reiniger, Lilla

    AU - Timár, Botond

    AU - Krenács, T.

    AU - Alizadeh, Hussain

    AU - Masszi, T.

    AU - Gaál-Weisinger, Júlia

    AU - Demeter, J.

    AU - Csomor, Judit

    AU - Matolcsy, A.

    AU - Kajtár, Béla

    AU - Bödör, Csaba

    PY - 2019/1/1

    Y1 - 2019/1/1

    N2 - Mutations of the multifunctional protein calreticulin (CALR) are recognised as one of the main driver alterations involved in the pathogenesis of Philadelphia negative myeloproliferative neoplasms (Ph– MPN) and also represent a major diagnostic criterion in the most recent World Health Organization classification of myeloid neoplasms. Nowadays, quantitative assessment of the driver mutations is gaining importance, as recent studies demonstrated the clinical relevance of the mutation load reflecting the size of the mutant clone. Here, we performed for the first time a manual and automated quantitative assessment of the CALR mutation load at protein level using CAL2, a recently developed CALR mutation specific monoclonal antibody, on a cohort of 117 patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF) and compared the CALR protein mutation loads with the CALR mutation load values established by a molecular assay. Eighteen different CALR mutations were detected in the cohort of the 91 CALR mutant cases. Mutation loads of the CALR mutations were between 13% and 94% with mean value in PMF cases significantly higher than ET cases (49.94 vs 41.09; t-test, p=0.004). Cases without CALR mutation (n=26) showed no or only minimal labelling with the CAL2 antibody, while all 18 different types of CALR mutations were associated with CAL2 labelling. The CALR mutation load showed a significant correlation (p=0.03) with the occurrence of major thrombotic events, with higher mutation load in patients presenting with these complications. We report a 100% concordance between the mutation status determined by immunohistochemistry and the CALR molecular assay, and we extend the applicability of this approach to 16 rare CALR mutations previously not analysed at protein level.

    AB - Mutations of the multifunctional protein calreticulin (CALR) are recognised as one of the main driver alterations involved in the pathogenesis of Philadelphia negative myeloproliferative neoplasms (Ph– MPN) and also represent a major diagnostic criterion in the most recent World Health Organization classification of myeloid neoplasms. Nowadays, quantitative assessment of the driver mutations is gaining importance, as recent studies demonstrated the clinical relevance of the mutation load reflecting the size of the mutant clone. Here, we performed for the first time a manual and automated quantitative assessment of the CALR mutation load at protein level using CAL2, a recently developed CALR mutation specific monoclonal antibody, on a cohort of 117 patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF) and compared the CALR protein mutation loads with the CALR mutation load values established by a molecular assay. Eighteen different CALR mutations were detected in the cohort of the 91 CALR mutant cases. Mutation loads of the CALR mutations were between 13% and 94% with mean value in PMF cases significantly higher than ET cases (49.94 vs 41.09; t-test, p=0.004). Cases without CALR mutation (n=26) showed no or only minimal labelling with the CAL2 antibody, while all 18 different types of CALR mutations were associated with CAL2 labelling. The CALR mutation load showed a significant correlation (p=0.03) with the occurrence of major thrombotic events, with higher mutation load in patients presenting with these complications. We report a 100% concordance between the mutation status determined by immunohistochemistry and the CALR molecular assay, and we extend the applicability of this approach to 16 rare CALR mutations previously not analysed at protein level.

    KW - CAL2 immunohistochemistry

    KW - calreticulin mutation

    KW - mutation load

    KW - Myeloproliferative neoplasms

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