[Predictive molecular pathological stratification of hematological neoplasms]. / Prädiktive molekularpathologische Stratifizierung hämatologischer Neoplasien.

The comprehensive sequencing of the complete genome of various hematological neoplasms has allowed an in-depth insight into the genomic heterogeneity and led to the discovery of new genetic aberrations, which seem to be very promising as therapeutic target structures. The molecular target structures of new therapeutic agents are, however, nearly exclusively proteins and cannot be directly identified with nucleic acid-based investigation methods. There is a great potential in investigations at the protein level that reflect an expression of the target protein and/or alterations of the signal cascade in tumor cells. In this context immunohistochemistry is a procedure that can deliver the decisive information using mutation, phosphorylation and glycosylation-specific primary antibodies. This study was carried out to comprehensively investigate the diagnostic utilization of such antibodies for hematological neoplasms. The studies summarized in this article emphasize the significance of tissue-based diagnostic approaches at the protein level and are suitable for use in patient selection for targeted treatment. A particular success of these studies was to make an essential contribution to the predictive diagnostics of multiple myeloma.

Impact of telomere length on survival in classic and variant hairy cell leukemia.

Telomeres, which protect the ends of chromosomes, are shortened in several hematologic malignancies, often with adverse prognostic implications, but their effect on prognosis of classic and variant hairy cell leukemia (HCL and HCLv) has not been reported. HCL/HCLv genomic DNA from 46 patients was studied by PCR to determine the ratio of telomere to single copy gene number (T/S). T/S was unrelated to diagnosis of HCL or HCLv (p=0.27), but shorter T/S was associated with unmutated immunoglobulin rearrangements (p=0.033) and age above the median at diagnosis (p=0.017). Low T/S was associated with shorter overall survival from diagnosis (OS), particularly T/S <0.655 (p=0.0064, adjusted p=0.019). Shorter OS was also associated with presence of unmutated (p<0.0001) or IGHV4-34+ (p<0.0001) rearrangements, or increasing age (p=0.0002). Multivariable analysis with Cox modeling showed that short T/S along with either unmutated or IGHV4-34+ rearrangements remained associated with reduced OS (p=0.0071, p=0.0024, respectively) after age adjustment. While T/S is relatively long in HCL and the disease usually indolent with excellent survival, shortened telomeres in HCL/HCLv are associated with decreased survival. Shortened T/S could represent a risk factor needing further investigation/intervention to determine if non-chemotherapy treatment options, in addition to or instead of chemotherapy, might be particularly useful.

Hairy cell leukemia: a 'hair-raising' update.

Hairy cell leukemia (HCL) is an uncommon low grade B cell leukemia that is marked by pancytopenia, splenomegaly, and characteristic cytoplasmic hairy projections. The current standard of care is treatment with purine analogs, like cladribine or pentostatin, which provide a high complete remission rate with a median duration of response of 5 years. Many patients who show initial remission will relapse, and others with refractory disease may show no response. The discovery of the BRAF mutation has created a therapeutic target exploited by oral inhibitors like vemurafenib and dabrafenib. Targeted immunotoxins remain an interesting area of study. The use of the monoclonal antibody rituximab in combination with purine analogs appears to produce even higher responses, often employed to minimize or eliminate residual disease. With our current understanding of B cell signaling pathways, the development of kinase inhibitors appears promising and may change the future therapeutic landscape of this rare disease.

Classical hairy cell leukemia and its variant: a 17-year retrospective survey in Taiwan Chinese.

BACKGROUND: Classical hairy cell leukemia (HCL-C) and its variant (HCL-V) are rare chronic B-cell lymphoproliferative disorders. Only a few reports in Chinese patients are available. METHODS: We retrospectively reviewed 16 patients with HCL-C and HCL-V in Taiwan over a 17-year period. RESULTS: Eight were HCL-C and 8 were HCL-V. All HCL accounted for 0.7% of all adult leukemias. Compared to HCL-V, HCL-C was characterized by profound leukopenia, monocytopenia, thrombocytopenia and fewer circulating hairy cells. One HCL-C and 2 HCL-V patients had second malignancies. Seven HCL-C patients achieved hematological remission after splenectomy (n = 1) or 2-chlorodeoxyadenosine (n = 6). Of the 8 HCL-V patients, 6 received splenic irradiation. Only one achieved complete remission and another had partial remission; relapse or disease progression was noted 13.4 or 25.7 months later, respectively. Two of three HCL-V patients who underwent splenectomy had stable disease. All patients with HCL-C were alive while 3 with HCL-V expired. Compared to HCL-C, HCL-V had a significantly shorter leukemia-free survival. CONCLUSION: A relatively higher proportion of HCL-V in all HCL comparing to Westerners is observed. Second malignancies are common. With an inferior outcome and dismal response to most treatment, enrollment in a clinical trial should be considered for HCL-V.

Management of hairy cell leukemia variant.

Hairy cell leukemia variant (HCL-V) is now included in the World Health Organization (WHO) classification as a provisional entity and is no longer considered to be biologically related to classic HCL (HCL-C). The clinical course of HCL-V is variable but usually more aggressive, and the median survival of patients with HCL-V is significantly shorter than that of HCL-C. The therapeutic approach to HCL-V is still debated. Various treatment approaches active in HCL-C achieve partial response (PR) or no response in HCL-V, and remission is usually shorter than in HCL-C. In addition, HCL-V seems to be resistant to therapeutic modalities usually highly effective in the treatment of HCL-C. Cladribine (2-CdA) is significantly less active in HCL-V than in HCL-C. In addition, the majority of patients with HCL-V require more than one cycle of 2-CdA to maintain PR. Patients with HCL-V treated with pentostatin also have a poorer clinical outcome and a lower response rate than those of patients with HCL-C. Recently, some reports indicate that monoclonal antibodies, rituximab and alemtuzumab, are active in HCL-V. Promising results have also been obtained with anti-CD22 immunotoxin, BL22. A new generation of CD22-specific immunotoxins, moxetumomab pasudotox (CAT-8015, HA22), highly active in refractory/relapsed HCL-C, also need clinical investigation in HCL-V. Currently, immunochemotherapy with rituximab and purine nucleoside analogs (PNAs) should be considered as the treatment of choice in previously untreated patients.

Immunophenotypic analysis of CD103+ B-lymphoproliferative disorders: hairy cell leukemia and its mimics.

CD103 is characteristically expressed in hairy cell leukemia (HCL), a B-lymphoproliferative disorder highly responsive to treatment with purine analogs. Other CD103+ diseases are rare and do not respond well to the same therapy, including HCL variant (HCLv) and splenic marginal zone B-cell lymphoma (SMZL) variants. We analyzed 215 cases of CD103+ B-lymphoproliferative disorders to further delineate their immunophenotypic features. Flow cytometric analysis revealed that 78.6% of all cases expressed CD25 and CD103, characteristic of classical HCL. Cases analyzed immunohistochemically were also invariably positive for annexin-A1; a subset coexpressed CD10 (33/169 [19.5%]) or BCL1 (26/65 [36.9%]). In contrast, 21.4% of cases lacked CD25, a subset of which was analyzed and was invariably negative for annexin-A1, CD10, and BCL1. The CD25- cases had variable morphologic features ranging from HCLv and SMZL to prolymphocytic leukemia and diffuse large B-cell lymphoma. Clinically, patients with CD25- disease tended to be older (P= .001), typically had leukocytosis (P= .014), and did not respond well to cladribine or pentostatin. We suggest categorizing CD103+ B-lymphoproliferative disorders into 2 groups. While HCL coexpresses CD25 and annexin-A1, diseases lacking CD25 and annexin-A1 behave clinically differently and can be separated from HCL on diagnosis.

Complete remission of hairy cell leukemia variant (HCL-v) complicated by red cell aplasia post treatment with rituximab.

Hairy cell leukemia variant (HCL-v) is a rare form of a chronic B-cell lymphoproliferative disorder. Unlike typical hairy cell leukemia (HCL) where the complete response (CR) rate to 2-chlorodeoxyadenosine and 2'-deoxycoformycin can approach about 90%, in HCL-v CR is rare and partial response (PR) occurs in approximately 50% with these agents. Rituximab treatment in relapsed or refractory HCL results in a CR of 13% to 53%, but its use in HCL-v has not been reported in the literature to our knowledge. We describe a patient with HCL-v, whose course was previously complicated by pure red cell aplasia who achieved CR after treatment with rituximab. We also briefly review outcomes of treatments used in HCL-v reported in the current literature.

Hairy cell leukemia variant: fact or fiction.

Hairy cell leukemia variant (HCL-V) is a poorly described, rare B-cell lymphoproliferative disorder typically positive for CD103 and CD11c, while lacking CD25. Splenic marginal zone lymphomas (SMZL) also have this unusual phenotype in 15% to 25% of cases, have other overlapping clinical or morphologic features, and are more common than HCL-V. The purpose of our study was to better characterize HCL-V and determine whether most cases could be distinguished from SMZL. Cases with an HCL-V phenotype were identified from our flow cytometry service, and 10 were selected for further study based on bone marrow or splenic tissue availability. All cases had cytologic features consistent with HCL-V, and 9 of 10 patients had lymphocytosis. Bone marrow involvement was mostly interstitial and/or sinusoidal without lymphoid nodules. Coexpression of preswitched with postswitched heavy chain isotypes, an unusual feature of HCL, was seen in 2 of 4 cases. This study better defines HCL-V and establishes that most cases do not represent SMZL.

Morphometric classification of hairy cell leukemia in bone marrow trephine biopsy.

OBJECTIVE: To analyze cytologic and histologic parameters in bone marrow trephine biopsy in an attempt to define heterogeneity of hairy cell leukemia cells. STUDY DESIGN: The study group consisted of 28 trephine biopsies. Immunohistochemistry for CD20 antigen was used. Image processing and measurements were performed with AnalySIS 3.0 image analysis system (Soft Imaging System GmbH, Germany) and custom built programs. For planimetric measurements of nuclei, automatic segmentation was implemented. The measured parameters were: surface area, perimeter, minimum, mean and maximum diameter, and a set of form factors. Relative volumes of bone trabeculae, adipose tissue, hematopoietic tissue and neoplastic infiltrate were assessed by the point counting method. Nuclear volume was measured by the point sampled intercept method. Bone marrow fibrosis was assessed using a curvilinear line test system. RESULTS: Significant variability of cell nuclei was found, and their classification into 3 types was possible. The relative frequency of those types was different in various cases and allowed subdivision of cases into 3 groups that differed in some clinical and histologic manifestations. CONCLUSION: The present study demonstrated the heterogeneity of cell populations of hairy cell leukemia.

[European-American-type hairy cell leukemia without splenomegaly, treated successfully with deoxycoformycin].

A 55-year-old Japanese man was hospitalized on October 5, 1999, because of high fever. Physical examination revealed neither lymphadenopathy nor hepato-splenomegaly. Laboratory data on admission showed a white blood cell count of 1,580/microliter, a hemoglobin level of 9.1 g/dl, and a platelet count of 113 x 10(3)/microliter. A small percentage of abnormal mononuclear cells were present in the peripheral blood. A bone marrow biopsy specimen demonstrated myelofibrosis and diffuse infiltration of abnormal monoculear cells with a mature B cell phenotype. A bone marrow aspirate showed 29% abnormal mononuclear cells, which had an indented or folded nucleus and reticular nuclear chromatin. Moderate to strong tartarate-resistant acid phosphatase activity was detected in these cells. Although the cytoplasmic projections were poorly preserved in specimens stained with May-Giemsa, fresh preparations showed numerous slender cytoplasmic projections by phase-contrast microscopy. The hairy cells had the phenotype CD5-, CD10-, CD11c+, CD19+, CD20+, CD25+, lambda. The patient was diagnosed as having European-American-type hairy cell leukemia (HCL) without splenomegaly, which is quite rare in Japan. The value of phase-contrast microscopy for recognition of the hairy cells was emphasized. The patient was treated successfully with deoxycoformycin (DCF).

Hairy cell leukemia variant.

A 59-year-old man presented with lymphocytosis with huge splenomegaly. The abnormal lymphocytes had a high nucleoplasm:cytoplasm ratio, a prominent nucleolus and hairy cytoplasmic projections. Immunophenotyping revealed B-cell leukemia with negative reactions to CD5 and CD25. Cytogenetic study showed 46,XY,der(5)t(5;6)(q35;p21), del(7)(p13)/46,idem,add(22)(q13). The patient did not respond to chlorambucil and a combination of cyclophosphamide, vincristine and prednisolone. Splenic irradiation induced partial remission. He developed progressive anemia and thrombocytopenia and died of Escherichia coli septicemia 33 months after the diagnosis of hairy cell leukemia variant.

Predominance of a distinct subtype of hairy cell leukemia in Japan.

Forty Japanese patients with hairy cell leukemia (HCL) were reviewed. Nine cases were diagnosed as typical HCL, and two cases had the features of HCL variant (prolymphocytic variant). The remaining 29 cases (72.5%) differed morphologically and hematologically from the other two groups in that they usually had a moderately high leukocyte count (average 27.9 x 10(3)/microliters), and abnormal cells showing a densely stained round nucleus and an inconspicuous nucleolus. Tartrate-resistant acid phosphatase reaction was weak, and their cells exhibited generally smooth or slightly irregular, cellular outlines in smears. The cells showed weak expression of surface immunoglobulin G (IgG) with kappa-chain predominance. CD25 antigen was not detected. Some of these findings resemble those of B-cell chronic lymphocytic leukemia, but the patients also had several important features of HCL. They had splenomegaly without significant lymphadenopathy. The abnormal cells were CD20+, CD11c+ and showed typical 'hairy morphology' under phase-contrast and scanning electron microscopy. Furthermore, spleen sections revealed diffuse infiltration by the abnormal cells in the red pulp. From these findings, we speculated that this group of patients constitute a distinct subtype of HCL which is commonly seen in Japan. We propose to term the disease as HCL Japanese variant.