Am J Blood Res 2013;3(2):181-185
Brief Communication
Absence of BRAF exon 15 mutations in multiple myeloma and Waldenström’s
macroglobulinemia questions its validity as a therapeutic target in plasma cell
neoplasias
Eleftheria Hatzimichael, Samuel Murray, Evangelos Briasoulis
Academic Department of Haematology, University Hospital of Ioannina, Ioannina, Greece; Computational Medicine Center,
Jefferson Medical College, Thomas Jefferson University, Philadelphia, USA; Biomarker Solutions Ltd, London, UK; GeneKor
R&D, Athens, Greece
Received January 23, 2013; Accepted March 11, 2013; Epub May 5, 2013; Published May 15, 2013
Abstract: Purpose: Recent whole genome and/or exome sequencing in a cohort of 32 Multiple Myeloma (MΜ) patients
reported the incidence of BRAF mutations at 4%, while in another exome sequencing study, BRAF mutations were reported in
up to 13% of cases tested. We ran a confirmatory study by using High Resolution Melting Analysis (HRMA), which is a low-
cost, straightforward and sensitive screening test for detection of BRAF exon 15 mutations in MM and Waldenström’s
macroglobulinemia (WM) patients, in order to investigate their incidence in every day clinical practice. We considered this
investigation to be of clinical relevance following the recent emergence of potent anti-BRAF compounds. Patients and
Methods: We used genomic DNA isolated from 31 bone marrow aspirates obtained from 25 MM patients and 3 patients with
WM (14 female; 14 male) who signed an informed consent. Patients’ median age was 69 years (range 43-86) and median
follow-up time was 45 months. Myeloma subtypes were as follows: 7 IgGκ, 6 IgGλ, 7 IgAλ, 4 IgAλ and 1 non-secretory. The
bone marrow plasma cells ranged from 12 to 100% (mean/median value 45%). By International Staging System (ISS) 9/25
patients were stage Ι, 6/25 stage ΙΙ, 7/25 stage ΙΙΙ, while in 3 cases staging information was missing. In 3 MM cases matched
paired samples at diagnosis and at relapse were also available. DNA samples were screened using HRMA. HRMA results
were confirmed by subsequent ds-bi-directional sequencing (Sanger method) for somatic mutations in exon 15 of BRAF.
Results: At a limit of detection ≥2.5% mutant allelic content by HRMA, we did not detect any BRAF mutations in exon 15 in any
of our 31 samples. Conclusions: By using HRMA we do not confirm previously reported results. Lack of detection of BRAF
exon 15 mutations in our MM and WM series may be related to different sensitivity of the assays used and/or the relatively
small sample size. In any case, we consider that existing data should be taken into account when considering the clinical
development of BRAF inhibitors in plasma cell neoplasms. (AJBR1301004).
Keywords: Multiple myeloma, BRAF, mutation, Waldenström’s macroglobulinemia, high resolution melting analysis
Address correspondence to: Dr. Eleftheria Hatzimichael, Haematologist, Computational Medicine Center, Jefferson Medical
College, Thomas Jefferson University, 1020 Locust Str, Suite M#81, PA 19107 Philadelphia, USA. E-mail: eleftheria.
chatzimichail@jefferson.edu
Brief Communication
Absence of BRAF exon 15 mutations in multiple myeloma and Waldenström’s
macroglobulinemia questions its validity as a therapeutic target in plasma cell
neoplasias
Eleftheria Hatzimichael, Samuel Murray, Evangelos Briasoulis
Academic Department of Haematology, University Hospital of Ioannina, Ioannina, Greece; Computational Medicine Center,
Jefferson Medical College, Thomas Jefferson University, Philadelphia, USA; Biomarker Solutions Ltd, London, UK; GeneKor
R&D, Athens, Greece
Received January 23, 2013; Accepted March 11, 2013; Epub May 5, 2013; Published May 15, 2013
Abstract: Purpose: Recent whole genome and/or exome sequencing in a cohort of 32 Multiple Myeloma (MΜ) patients
reported the incidence of BRAF mutations at 4%, while in another exome sequencing study, BRAF mutations were reported in
up to 13% of cases tested. We ran a confirmatory study by using High Resolution Melting Analysis (HRMA), which is a low-
cost, straightforward and sensitive screening test for detection of BRAF exon 15 mutations in MM and Waldenström’s
macroglobulinemia (WM) patients, in order to investigate their incidence in every day clinical practice. We considered this
investigation to be of clinical relevance following the recent emergence of potent anti-BRAF compounds. Patients and
Methods: We used genomic DNA isolated from 31 bone marrow aspirates obtained from 25 MM patients and 3 patients with
WM (14 female; 14 male) who signed an informed consent. Patients’ median age was 69 years (range 43-86) and median
follow-up time was 45 months. Myeloma subtypes were as follows: 7 IgGκ, 6 IgGλ, 7 IgAλ, 4 IgAλ and 1 non-secretory. The
bone marrow plasma cells ranged from 12 to 100% (mean/median value 45%). By International Staging System (ISS) 9/25
patients were stage Ι, 6/25 stage ΙΙ, 7/25 stage ΙΙΙ, while in 3 cases staging information was missing. In 3 MM cases matched
paired samples at diagnosis and at relapse were also available. DNA samples were screened using HRMA. HRMA results
were confirmed by subsequent ds-bi-directional sequencing (Sanger method) for somatic mutations in exon 15 of BRAF.
Results: At a limit of detection ≥2.5% mutant allelic content by HRMA, we did not detect any BRAF mutations in exon 15 in any
of our 31 samples. Conclusions: By using HRMA we do not confirm previously reported results. Lack of detection of BRAF
exon 15 mutations in our MM and WM series may be related to different sensitivity of the assays used and/or the relatively
small sample size. In any case, we consider that existing data should be taken into account when considering the clinical
development of BRAF inhibitors in plasma cell neoplasms. (AJBR1301004).
Keywords: Multiple myeloma, BRAF, mutation, Waldenström’s macroglobulinemia, high resolution melting analysis
Address correspondence to: Dr. Eleftheria Hatzimichael, Haematologist, Computational Medicine Center, Jefferson Medical
College, Thomas Jefferson University, 1020 Locust Str, Suite M#81, PA 19107 Philadelphia, USA. E-mail: eleftheria.
chatzimichail@jefferson.edu
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