[Recurrent somatic mutation in hairy cell leukemia.]

Semmelweis Egyetem, Általános Orvostudományi Kar I. Belgyógyászati Klinika Budapest Korányi S. u. 2/a 1083.
Orvosi Hetilap 01/2013; 154(4):123-127. DOI: 10.1556/OH.2013.29531
Source: PubMed


Hairy cell leukemia is a mature B-cell non-Hogkin lymphoma characterized by unique clinical, morphological and immunhistochemical features. Patients with hairy cell leukemia usually present with splenomegaly, progressive pancytopenia and a relative indolent clinical course. The diagnosis does not always indicate immediate treatment, as treatment depends on the clinical stage of the leukemia. Asymptomatic disease without progression requires a watchful waiting policy, while other categories usually need treatment. The treatment of choice is purin nucleosid analogues (pentostatin, cladribine) which can achieve complete remission even for decades. Interferon and monoclonal CD20 antibodies can also significantly prolong tevent free survival. Unfortunately, only the latter two therapies are easily available in Hungary. Splenectomy, which was suggested as first line treatment before the era of purin nucleosid analogues, is only recommended as ultimum refugium. Although hairy cell leukemia is a well-defined lymphoproliferative disease, sometimes it is difficult to differentiate it from other similar entities such as hairy cell leukema variant, splenic marginal zone lymphoma, small lymphocytic lymphoma etc. Making the correct diagnosis is of utmost importance because of the great difference in treatment modalities. Recently, a somatic mutation was found in all analysed hairy cell leukemia samples, but not in other splenic B-cell lymphomas. This article reviews the significance of this observation and presents the different types of methods for the detection of this mutation. Orv. Hetil., 2013, 154, 123-127.

1 Follower
8 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: In recent times BRAF V600E mutations have emerged as a genetic hallmark of hairy cell leukemia (HCL). This specific point mutation is present in virtually all cases of HCL but is exceedingly rare in other peripheral B-cell neoplasms. In this study we investigated the application of a BRAF V600E mutation-specific antibody (clone VE1) to differentiate HCL from HCL mimics, such as HCL variant and splenic marginal zone lymphoma. A total of 52 routinely processed formalin-fixed paraffin-embedded tissue specimens were investigated (bone marrow, n=46; spleen, n=6) for expression of V600E-mutated BRAF protein. All 32 cases of HCL were scored positive, and all non-HCL cases were scored negative. In 28 of 30 HCL cases the presence of a BRAF V600E mutation could be confirmed by direct sequencing, whereas no BRAF mutations were detected among 20 HCL mimics. We further screened 228 mature B-cell neoplasms with VE1 and detected 1 positive case of chronic lymphocytic leukemia. Sequencing confirmed the presence of a BRAF V600E mutation. In conclusion, we demonstrate that VE1 immunohistochemistry can be used to reliably differentiate HCL from HCL-mimicking entities. This on-slide technique might be particularly helpful in interpreting challenging biopsies with low tumor content.
    The American journal of surgical pathology 04/2012; 36(12). DOI:10.1097/PAS.0b013e3182549b50 · 5.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The somatically acquired V600E mutation of the BRAF gene has been recently described as a molecular marker of hairy cell leukemia (HCL). We developed an allele-specific PCR for this mutation and studied 62 patients with HCL, 1 with HCL variant, 91 with splenic marginal zone lymphoma, 29 with Waldenström macroglobulinemia, and 57 with B-cell chronic lymphoproliferative disorders. The BRAF V600E mutation was detected in all HCL cases and in only 2 of the remaining 178 patients. These 2 subjects had B-cell chronic lymphoproliferative disorders that did not fulfill the diagnostic criteria for HCL. Despite the positive PCR finding, the mutation could not be detected by Sanger sequencing in these 2 cases, suggesting that it was associated with a small subclone. We conclude that the BRAF V600E mutation is present in all patients with HCL and that, in combination with clinical and morphologic features, represents a reliable molecular marker for this condition.
    Blood 11/2011; 119(1):188-91. DOI:10.1182/blood-2011-08-368209 · 10.45 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hairy cell leukemia has been shown to be strongly associated with the BRAF V600E mutation. We screened 59 unenriched archived bone marrow aspirate and peripheral blood samples from 51 patients with hairy cell leukemia using high resolution melting analysis and confirmatory Sanger sequencing. The BRAF V600E mutation was detected in 38 samples (from 36 patients). The BRAF V600E mutation was detected in all samples with disease involvement above the limit of sensitivity of the techniques used. Thirty-three of 34 samples from other hematologic malignancies were negative for BRAF mutations. A BRAF K601E mutation was detected in a patient with splenic marginal zone lymphoma. Our data support the recent finding of a disease defining point mutation in hairy cell leukemia. Furthermore, high resolution melting with confirmatory Sanger sequencing are useful methods that can be employed in routine diagnostic laboratories to detect BRAF mutations in patients with hairy cell leukemia and related lymphoproliferative disorders.
    Haematologica 12/2011; 97(5):780-3. DOI:10.3324/haematol.2011.054874 · 5.81 Impact Factor
Show more