Prognostic impact of blast cell counts in dysplastic bone marrow disorders (MDS and CMML I) with concomitant fibrosis.

In a retrospective study, 43 patients with dysplastic neoplasms of the bone marrow (myelodysplastic syndromes and myelodysplastic/myeloproliferative-overlap neoplasms) associated with marked (grades 2-3) fibrosis were examined. Histopathologic and morphologic findings as well as cytogenetic and molecular results were correlated with clinical endpoints. Multilineage dysplasia (34 of 43 patients, 79 %) and hypercellular bone marrow (64 %) were found in most patients. In ten of 35 patients, poor risk karyotypes according to the International Prognostic Scoring System (IPSS) were recorded. The JAK2 V617F mutation was detected in four of 30 patients (13 %), and the KIT D816V mutation was found in two of 30 patients (6 %). Patients were mainly treated with palliative drugs and best supportive care. After an observation time of 1-41 (median 21) months, ten of 43 patients (23 %) had developed a secondary acute leukemia. The median survival of all 43 patients was 21.4 months (range 1.8-88.2 months). Of all prognostic parameters examined, the blast cell count at diagnosis was found to be a most reliable and most predictive marker concerning survival and leukemia progression. This confirms previous studies in dysplastic bone marrow neoplasms without fibrosis.

Oncostatin M is a FIP1L1/PDGFRA-dependent mediator of cytokine production in chronic eosinophilic leukemia.

BACKGROUND: Chronic eosinophilic leukemia (CEL) is a myeloproliferative neoplasm characterized by expansion of neoplastic eosinophils, tissue infiltration, and organ damage. In a subset of these patients, the FIP1L1/PDGFRA (F/P) oncoprotein is detectable. F/P exhibits constitutive tyrosine kinase activity and activates a number of signaling pathways. So far, however, little is known about the role of F/P-dependent proteins in the pathogenesis of CEL. METHODS: A screen for F/P-dependent cytokines was performed in growth factor-dependent human cell lines lentivirally transduced with F/P. Signal transduction pathways were characterized in Ba/F3 cells with doxycycline-inducible expression of F/P and in EOL-1 cells. Cytokine expression was confirmed in patients' material by immunohistochemistry, immunofluorescence, and confocal microscopy. Gene expression analysis, proliferation assays, and chemotaxis assays were used to elucidate paracrine interactions between neoplastic eosinophils and stromal cells. RESULTS: We show that F/P upregulates expression of oncostatin M (OSM) in various cell line models in a STAT5-dependent manner. Correspondingly, neoplastic eosinophils in the bone marrow were found to overexpress OSM. OSM derived from F/P + cells stimulated proliferation of stromal cells. Moreover, OSM-containing supernatants from F/P + cells were found to upregulate production of stromal cell-derived factor-1 (SDF-1)/CXCL12 in human fibroblasts. SDF-1, in turn, induced migration of EOL-1 cells in a dose-dependent manner. CONCLUSIONS: We have identified a F/P-driven paracrine interaction between neoplastic eosinophils and stromal cells that may contribute to tissue fibrosis and accumulation of neoplastic eosinophils in CEL.

Dermal infiltrates of cutaneous T-cell lymphomas with epidermotropism but not other cutaneous lymphomas are abundant with langerin⁺ dendritic cells.

BACKGROUND: The Langerhans cell (LC) hypothesis suggests that cutaneous T-cell lymphomas (CTCL) are diseases of chronic T-cell stimulation by LC-mediated antigen presentation. OBJECTIVE: To investigate a broad panel of CTCL and cutaneous B-cell lymphomas (CBCL) for the spatial association of langerin(+) dendritic cells (DC) with T and B cells in the skin, respectively. METHODS: Fifty-five specimens of CTCL and 10 of CBCL were double-stained with monoclonal antibodies against langerin and CD3 or CD20, respectively, and evaluated by confocal laser scan microscopy. RESULTS: Dermal infiltrates in mycosis fungoides (n = 38), primary cutaneous CD4+ small/medium-sized pleomorphic T-cell lymphoma (n = 3) and primary cutaneous peripheral T-cell lymphoma, unspecified (n = 3) were characterized by a high frequency of dermal langerin(+) DCs. These cells were exclusively present in the malignant infiltrates. No direct co-localization of CD3 and langerin could be resolved. Dermal langerin(+) cells were detected only in one of six primary cutaneous anaplastic large cell lymphomas (C-ALCL), characterized by epidermotropism. In other C-ALCL cases (five of six), in lymphomatoid papulosis (n = 3), subcutaneous panniculitis-like T-cell lymphoma (n = 2), and all variants of CBCL no dermal langerin(+) DCs could be found. CONCLUSIONS: Langerin(+) DCs are abundant in the dermal infiltrates of T-cell lymphomas with specific involvement of the epidermis. This might indicate that immature LC and neoplastic T cells interact and gives rise to further studies to characterize the phenotype of the langerin(+) cell population described here and its role in the pathology of CTCL.

Tumor mutational burden and immune infiltrates in renal cell carcinoma and matched brain metastases.

BACKGROUND: Tumor mutational burden (TMB) and density of tumor-infiltrating lymphocytes (TIL) have been postulated as predictive biomarkers for immunotherapy. Therefore, we investigated the concordance of TMB and TIL of primary/extracranial renal cell carcinoma (RCC) specimens and matched brain metastases (BM). PATIENTS AND METHODS: Twenty specimens from 10 patients were retrieved from the Vienna Brain Metastasis Registry (6/10 primary tumor, 4/10 lung metastasis, 10/10 matched BM). TMB was assessed using the TruSight Oncology 500 gene panel with libraries sequenced on a NextSeq instrument. TIL subsets (CD3+, CD8+, CD45RO+, FOXP3+, PD-L1+) were investigated using immunohistochemistry (Ventana Benchmark Ultra system) and automated tissue analysis (Definiens software). RESULTS: No significant difference in TMB, CD3+, CD8+, CD45RO+, FOXP3+ or PD-L1+ expression was observed between extracranial and matched intracranial specimens (P > 0.05). Higher CD8+ TIL (P = 0.053) and CD45RO+ TIL (P = 0.030) densities in the primary tumor compared with the intracranial samples were observed in specimens collected after exposure to systemic treatment. Neither extracranial sample origin (lung metastasis versus primary RCC) nor extracranial disease status at BM diagnosis (progressive versus stable disease) were significantly associated with TMB or TIL densities in extracranial and intracranial samples (P > 0.05). No significant correlation was found between the median differences of TMB or TIL densities from extracranial to intracranial samples and BM-free survival. CONCLUSION: The comparable immunological microenvironment of extra- and intracranial tumor samples in our study underscores the immunological activation also in BM from RCC, and therefore, supports the development of immune modulatory treatments also in patients with brain metastatic RCC.

Applied precision cancer medicine in metastatic biliary tract cancer.

INTRODUCTION: Advanced therapy-refractory biliary tract cancer (BTC) has poor prognosis and constitutes a major challenge for adequate treatment strategies. By mapping the molecular profiles of advanced BTC patients, precision cancer medicine may provide targeted therapies for these patients. OBJECTIVE: In this analysis, we aimed to show the potential of PCM in metastatic BTC. METHODS: In this single-center, real-world retrospective analysis of our PCM platform, we describe the molecular profiling of 30 patients diagnosed with different types of metastatic BTC. Tumor samples of the patients were examined using a 161-gene next-generation sequencing panel, immunohistochemistry (IHC), and fluorescence in situ hybridization for chromosomal translocations. RESULTS: In total, we identified 35 molecular aberrations in 30 patients. The predominant mutations were KRAS (n = 8), TP53 (n = 7), IDH2 (n = 4), and IDH1 (n = 3) that accounted for the majority of all molecular alterations (62.86%). BRAF mutations were observed in two patients. Less frequent alterations were noted in ARID1A, CTNNB1, ESR1, FBXW7, FGFR2, MET, NOTCH2, PIK3CA, PTCH1, SMAD4, and SRC1, each in one case. FGFR fusion gene was detected in one patient. No mutations were detected in eight patients. IHC revealed EGFR and p-mTOR expression in 28 patients. Applying these results to our patients, targeted therapy was recommended for 60% of the patients (n = 18). One patient achieved stable disease. CONCLUSIONS: PCM is a feasible treatment approach and may provide molecular-guided therapy recommendations for metastatic BTC.

Pax5 immunostaining in paraffin-embedded sections of canine non-Hodgkin lymphoma: a novel canine pan pre-B- and B-cell marker.

The Pax5 gene encodes the B-cell specific activator protein (BSAP), a member of the highly conserved paired box (PAX)-domain family of transcription factors and a key regulator in the development and differentiation of B-cells. Pax5 serves as a valuable B-cell marker in the classification of human lymphoma patients as it is restricted to lymphomas of B-cell lineage. In dogs, detection of Pax5 protein in lymphoma tissue has not been reported. Therefore, we have investigated the expression and detection of BSAP using a monoclonal anti-Pax5 antibody (anti-BSAP, clone 24) in canine lymphoma tissue samples to evaluate its diagnostic relevance as a B-cell marker. A series of 25 lymph nodes from 23 canine non-Hodgkin lymphoma patients, a reactive canine lymph node, and a normal non-reactive canine lymph node, were evaluated. All B-cell non-Hodgkin lymphomas (15) were found to express Pax5 protein. In addition, there was a strong correlation between Pax5 and CD79a expression. Three CD3 positive and five CD3 and CD79a positive lymphomas were immunophenotypically negative for anti-Pax5, indicating a T-cell lineage. In conclusion, anti-Pax5 antibody may offer an excellent B-cell marker in canine lymphomas.

Applied Precision Cancer Medicine in Neuro-Oncology.

Brain tumours that are refractory to treatment have a poor prognosis and constitute a major challenge in offering effective treatment strategies. By targeting molecular alterations, precision cancer medicine may be a viable option for the treatment of brain tumours. In this retrospective analysis of our PCM platform, we describe the molecular profiling of primary brain tumours from 50 patients. Tumour samples of the patients were examined by a 161-gene next-generation sequencing panel, immunohistochemistry, and fluorescence in situ hybridization (FISH). We identified 103 molecular aberrations in 36 (72%) of the 50 patients. The predominant mutations were TP53 (14.6%), IDH1 (9.7%) and PIK3CA (6.8%). No mutations were detected in 14 (28%) of the 50 patients. IHC demonstrated frequent overexpression of EGFR and mTOR, in 38 (76%) and 35 (70%) patients, respectively. Overexpression of PDGFRa and PDGFRb were less common and detected in 16 and four patients, respectively. For 35 patients a targeted therapy was recommended. In our database, the majority of patients displayed mutations, against which targeted therapy could be offered. Based on our observations, PCM may be a feasible novel treatment approach in neuro-oncology.

Chronic autoimmune thyroiditis (Hashimoto's thyroiditis) in patients with MALT lymphoma.

BACKGROUND: Autoimmune diseases have been implicated in the genesis of MALT lymphoma of various localizations. The development of thyroidal MALT lymphoma has been described as an adverse event in patients suffering from long-standing chronic autoimmune thyroiditis (CAT, Hashimoto's thyroiditis). The percentage and possible association between CAT and extrathyroidal MALT lymphoma, however, have not been assessed so far. PATIENTS AND METHODS: A retrospective analysis of 80 patients with MALT lymphoma diagnosed and treated at our institution identified a total of 13 patients (16%) with MALT lymphoma suffering from an underlying CAT. Patient characteristics including site of disease, stage, genetic changes and clinical course were assessed and evaluated. RESULTS: In total, 10 patients were female and 3 male, with the median age being 57 years (range: 31-80). Four patients suffered from thyroidal lymphoma and nine patients had extrathyroidal lymphoma (four gastric, two orbital, one small intestinal and two salivary gland lymphomas). Three patients had a long-standing history of CAT at diagnosis of MALT lymphoma, while CAT was discovered during staging and clinical work-up of MALT lymphoma in the remaining 10 patients. All 13 patients had localized disease, i.e. stage I or II. Only one of the four patients with gastric MALT lymphoma responded to antibiotic treatment against Helicobacter pylori infection. Genetic aberrations were detected in four patients, two of whom had a t(11;18)(q21;q21) translocation, one patient had trisomies 3 and 18 and one had trisomy 18. CONCLUSION: Our findings suggest that CAT is found in patients with not only thyroidal but also nonthyroidal MALT lymphoma. While the nature of our data does not allow for delineation of a direct association between CAT and development of extrathyroidal MALT lymphoma, further prospective studies on this issue are warranted.

Immunohistochemical assessment of CD25 is equally sensitive and diagnostic in mastocytosis compared to flow cytometry.

BACKGROUND: Systemic mastocytosis (SM) is a clonal myeloid disorder characterized by abnormal accumulation and growth of mast cells (MC) in internal organs. In most cases, the bone marrow is involved. Expression of CD25 in bone marrow MC, with or without coexpression of CD2, is an important minor SM criterion. So far, most studies have examined CD25-expression on MC by flow cytometry. MATERIALS AND METHODS: We examined the expression of CD25 in MC in patients with SM (n = 25) by immunohistochemistry (IHC) and compared these data with results obtained by flow cytometric assessment of CD25-expression. In addition, we compared CD25-staining results with that obtained with an antibody against CD2. RESULTS: In a majority of all patients (> 80%), CD25 was detectable by both staining techniques. However, in one patient, CD25 was only detectable on MC by IHC, but not by flow cytometry, and in two patients in whom IHC could not be applied because of lack of compact MC infiltrates, flow cytometry revealed aberrant expression of CD25. The antibody against CD2 produced diagnostic staining results in a smaller group of patients (flow cytometry: 65%; IHC: 28% of SM cases) compared to CD25 (> 80%). CONCLUSIONS: CD25-IHC is equally diagnostic and sensitive in SM compared to flow cytometry and thus can be recommended as a diagnostic test. Our data also suggest that the diagnostic value of CD25 exceeds that of CD2, and that optimal assessment of CD25-expression in neoplastic MC in all patients requires the application of both techniques, flow cytometry and IHC.

Mixed-lineage eosinophil/basophil crisis in MDS: a rare form of progression.

BACKGROUND: Basophilic crisis and eosinophilia are well recognized features of advanced chronic myeloid leukaemia. In other myeloid neoplasms, however, transformation with marked basophilia and eosinophilia is considered unusual. DESIGN: We examined the long-term follow-up of 322 patients with de novo myelodysplastic syndromes (MDS) to define the frequency of basophilic, eosinophilic and mixed lineage (basophilic and eosinophilic) transformation. RESULTS: Of all patients, only one developed mixed lineage crisis (>or= 20% basophils and >or= 20% eosinophils). In this patient, who initially suffered from chronic myelomonocytic leukaemia, basophils increased to 48% and eosinophils up to 31% at the time of progression. Mixed lineage crisis was not accompanied by an increase in blast cells or organomegaly. The presence of BCR/ABL and other relevant fusion gene products (FIP1L1/PDGFRA, AML1/ETO, PML/RAR alpha, CBF beta/MYH11) were excluded by PCR. Myelomastocytic transformation/myelomastocytic leukaemia and primary mast cell disease were excluded by histology, KIT mutation analysis, electron microscopy and immunophenotyping. Basophils were thus found to be CD123+, CD203c+, BB1+, KIT- cells, and to express a functional IgE-receptor. Among the other patients with MDS examined, 4(1.2%) were found to have marked basophilia (>or= 20%) and 7(2.1%) were found to have massive eosinophilia ( >or= 20%), whereas mixed-lineage crisis was detected in none of them. CONCLUSIONS: Mixed basophil/eosinophil crisis may develop in patients with MDS but is an extremely rare event.

MALT lymphoma in patients with autoimmune diseases: a comparative analysis of characteristics and clinical course.

MALT lymphoma, especially of extragastric origin, is thought to be associated with an underlying autoimmune disease (AD) in a significant proportion of patients. No systematic assessment of the clinical characteristics of MALT lymphoma arising in AD as opposed to patients without AD has been performed so far. Therefore, all patients diagnosed and treated for MALT lymphoma at our institution have prospectively undergone routine clinical and serological assessment for AD since 1997. In total, 158 patients were available for analysis, and 61 out of 158 patients (39%) were diagnosed with an underlying AD. Patients with AD were predominantly women and significantly younger at lymphoma diagnosis (56 versus 67 years, P=0.004), with a significantly higher rate of extragastric lymphomas (P=0.012). Furthermore, lymphomas in these patients showed a lower frequency of trisomy 3 (P=0.04) and a significantly lower response rate to Helicobacter pylori eradication therapy in the case of gastric lymphomas (P=0.03). All other parameters including estimated median time to relapse were comparable between both groups. Our data suggest that patients with AD develop MALT lymphoma significantly earlier in life. The clinical course, however, does not appear to be adversely influenced by the presence of AD, as neither rate of relapse nor times to relapse or survival are significantly different.

Pathology and clinical course of MALT lymphoma with plasmacytic differentiation.

BACKGROUND: The feature of plasmacytic differentiation (PCD) is present in up to 30% of patients diagnosed with mucosa-associated lymphoid tissue (MALT) lymphoma. To date, the influence of PCD on the clinical course of MALT lymphoma has not been assessed. PATIENTS AND METHODS: Therefore, we have retrospectively analysed the clinical characteristics and the course of the disease in 34 (25%) patients with PCD as compared with 101 (75%) MALT lymphoma patients without this histological feature. RESULTS: Patients with PCD had significantly more extragastric lymphomas [28 of 34 (82%) versus 54 of 101 (53%), P = 0.003] and a significantly lower rate of t(11;18) [2 of 26 (8%) versus 22 of 72 (31%), P = 0.02]. There was no significant difference of age at diagnosis (62 versus 64 years, P = 0.64), relapse rate (48% versus 37%, P = 0.27), estimated median time to progression (43 versus 65 months, P = 0.14), monoclonal gammopathy (50% versus 44%, P = 0.63), t(14;18) involving IGH/MALT 1 (11% versus 8%, P = 0.68), trisomy 3 (31% versus 27%, P = 0.69), trisomy 18 (8% versus 10%, P = 0.74) and the presence of autoimmune diseases between both groups (53% versus 37%, P = 0.09). CONCLUSION: In conclusion, we found that PCD is predominantly found in extragastric MALT lymphoma but has no significant impact on clinical course and prognosis.

Resistance to oncogenic transformation in revertant R1 of human ras-transformed NIH 3T3 cells.

A flat revertant, R1, was isolated from human activated c-Ha-ras-1 (hu-ac-Ha-ras) gene-transformed NIH 3T3 cells (EJ-NIH 3T3) treated with mutagens. R1 contained unchanged transfected hu-ac-Ha-ras DNA and expressed high levels of hu-ac-Ha-ras-specific mRNA and p21 protein. Transfection experiments revealed that NIH 3T3 cells could be transformed by DNA from R1 cells but R1 cells could not be retransformed by Kirsten sarcoma virus, DNA from EJ-NIH 3T3 cells, hu-ac-Ha-ras, v-src, v-mos, simian virus 40 large T antigen, or polyomavirus middle T antigen. Somatic cell hybridization studies showed that R1 was not retransformed by fusion with NIH 3T3 cells and suppressed anchorage independence of EJ-NIH 3T3 and hu-ac-Ha-ras gene-transformed rat W31 cells in soft agar. These results suggest that the reversion and resistance to several oncogenes in R1 is due not to cellular defects in the production of the transformed phenotype but rather to enhancement of cellular mechanisms that suppress oncogenic transformation.

Enumeration and immunohistochemical characterisation of bone marrow basophils in myeloproliferative disorders using the basophil specific monoclonal antibody 2D7.

BACKGROUND: Basophils are highly specialised granulocytes that express a unique profile of antigens and increase in myeloproliferative disorders (MPD). In chronic myeloid leukaemia (CML), basophilia is a diagnostic and prognostic determinant. So far, however, no reliable approach for routine detection and enumeration of bone marrow basophils has become available. OBJECTIVE: To detect and enumerate basophils in bone marrow sections in patients with CML and other MPD. METHODS: The anti-basophil antibody 2D7 was applied to paraffin embedded bone marrow sections from normal/reactive subjects (n = 31), patients with CML (chronic phase, n = 37; accelerated phase, n = 9), and other MPD (chronic idiopathic myelofibrosis (CIMF), n = 20; polycythaemia vera (PV), n = 20; essential thrombocythaemia (ET), n = 20; indolent systemic mastocytosis (ISM), n = 7). RESULTS: As assessed by serial section staining, 2D7(+) cells were found to co-express myeloperoxidase, histidine decarboxylase, CD9, and CD43, but did not express B cell or T cell restricted antigens. 2D7(+) bone marrow cells were found to increase in CML compared with normal/reactive bone marrow and other MPD (median numbers of 2D7(+) cells/mm(2): CML, 33; normal/reactive bone marrow, 6; CIMF, 10; PV, 6; ET, 5; ISM, 3; p<0.05). The highest basophil counts were recorded in accelerated phase CML (115/mm(2)). CONCLUSIONS: A novel immunohistochemical procedure has been established for basophil detection in normal bone marrow and MPD. This approach should help in the quantification of bone marrow basophils at diagnosis and during anti-leukaemic treatment.

Gelsolin: a candidate for suppressor of human bladder cancer.

Human transitional cell carcinomas of the bladder frequently reveal chromosomal abnormalities that span a range between chromosome 9p12 and 9qter, even at early stages of bladder carcinogenesis. Because the gene that encodes an actin-regulatory protein, gelsolin, is localized in chromosome 9q33, we examined the expression of gelsolin in a number of human bladder cancer cell lines and tissues. In all 6 cell lines and in 14 of the 18 tumor tissues (77.8%), gelsolin expression was undetectable or extremely low in comparison with its expression in normal bladder epithelial cells. Furthermore, upon the introduction of the exogenous human or mouse authentic gelsolin cDNA into a human bladder cancer cell line, UMUC-2, gelsolin transfectants of UMUC-2 greatly reduced the colony-forming ability and the tumorigenicity in vivo. These results suggest that gelsolin plays a key role as a tumor suppressor in human urinary bladder carcinogenesis.

Programmed death-ligand 1 expression in rectal cancer.

BACKGROUND: Colorectal cancer (CRC) is the fourth most common cause of death worldwide. Approximately 30 % of all CRC occurs in the rectum. Improvements in survival rates were achieved thanks to multimodal therapy, combining surgery and chemoradiation. Nevertheless, the prognosis of patients suffering from rectal cancer (RC) remains poor. Programmed cell death protein 1 (PD-1) and its ligand programmed death ligand 1 (PD-L1) regulate tumor immune response. The aim of this study was to analyze the expression of PD-L1 in RC pre- and post-neoadjuvant therapy and evaluate PD-L1 as a biomarker and potential target for therapy. METHODS: In all, 29 patients with RC treated at the Medical University Vienna who received preoperative chemoradiation were retrospectively enrolled in this study. Expression of PD-L1 was investigated by immunohistochemistry with two different anti-PD-L1 antibodies. RESULTS: No PD-L1 expression on cancer cells could be observed in all 29 cases in the specimens before chemoradiation as well as in the surgical specimens after neoadjuvant therapy. In one of the two staining methods performed, five (17.24 %) post-chemoradiation cases showed faint lymphohistiocytic staining. CONCLUSION: No expression of PD-L1 in RC cells before and after chemoradiation was found in our collective of 29 patients. Further investigations to evaluate the role of PD-L1 as a potential therapeutic target in RC are urgently needed.

HSP27 and 70 expression in thymic epithelial tumors and benign thymic alterations: diagnostic, prognostic and physiologic implications.

Thymic Epithelial Tumors (TETs), the most common tumors in the anterior mediastinum in adults, show a unique association with autoimmune Myasthenia Gravis (MG) and represent a multidisciplinary diagnostic and therapeutic challenge. Neither risk factors nor established biomarkers for TETs exist. Predictive and diagnostic markers are urgently needed. Heat shock proteins (HSPs) are upregulated in several malignancies promoting tumor cell survival and metastases. We performed immunohistochemical staining of HSP27 and 70 in patients with TETs (n = 101) and patients with benign thymic alterations (n = 24). Further, serum HSP27 and 70 concentrations were determined in patients with TETs (n = 46), patients with benign thymic alterations (n = 33) and volunteers (n = 49) by using ELISA. HSPs were differentially expressed in histologic types and pathological tumor stages of TETs. Weak HSP tumor expression correlated with worse freedom from recurrence. Serum HSP concentrations were elevated in TETs and MG, correlated with clinical tumor stage and histologic subtype and decreased significantly after complete tumor resection. To conclude, we found HSP expression in the vast majority of TETs, in physiologic thymus and staining intensities in patients with TETs have been associated with prognosis. However, although interesting and promising the role of HSPs in TETs as diagnostic and prognostic or even therapeutic markers need to be further evaluated.

Clinical impact of bone marrow morphology for the diagnosis of essential thrombocythemia: comparison between the BCSH and the WHO criteria.

Essential thrombocythemia (ET) is currently diagnosed either by the British Committee of Standards in Haematology (BCSH) criteria that are predominantly based on exclusion and not necessarily on bone marrow (BM) morphology, or the World Health Organization (WHO) criteria that require BM examination as essential criterion. We studied the morphological and clinical features in patients diagnosed according either to the BCSH (n=238) or the WHO guidelines (n=232). The BCSH-defined ET cohort was re-evaluated by applying the WHO classification. At presentation, patients of the BCSH group showed significantly higher values of serum lactate dehydrogenase and had palpable splenomegaly more frequently. Following the WHO criteria, the re-evaluation of the BCSH-diagnosed ET cohort displayed a heterogeneous population with 141 (59.2%) ET, 77 (32.4%) prefibrotic primary myelofibrosis (prePMF), 16 (6.7%) polycythemia vera and 4 (1.7%) primary myelofibrosis. Contrasting WHO-confirmed ET, the BCSH cohort revealed a significant worsening of fibrosis-free survival and prognosis. As demonstrated by the clinical data and different outcomes between WHO-diagnosed ET and prePMF, these adverse features were generated by the inadvertent inclusion of prePMF to the BCSH group. Taken together, the diagnosis of ET without a scrutinized examination of BM biopsy specimens will generate a heterogeneous cohort of patients impairing an appropriate clinical management.

Tumor-suppressive function of mutated gelsolin in ras-transformed cells.

The flat revertant R1, isolated from human activated Ha-ras oncogene-transformed NIH3T3 fibroblasts (EJ-NIH3T3), expresses a variant form of the actin-regulatory protein gelsolin (p92-5.7). We have cloned cDNAs encoding p92-5.7 and identified as the cause of the expression of p92-5.7 a point mutation in codon 321, which results in an amino acid change from proline to histidine. In order to understand the role of p92-5.7 in reversion of ras-transformed cells, cDNAs encoding p92-5.7 or human authentic gelsolin as a control were transfected into EJ-NIH3T3 cells. All the transfectants that produced p92-5.7 and one of three transfectants that produced human authentic gelsolin either lost or reduced tumorigenicity in syngeneic mice. These results demonstrate that mutated gelsolin can suppress a ras tumor and suggest that authentic gelsolin, if expressed at increased levels, may have a similar suppressive potential. Our data propose an important role for gelsolin in cellular signal transduction pathways that involve the mammalian ras proto-oncogene.

Variable frequencies of MALT lymphoma-associated genetic aberrations in MALT lymphomas of different sites.

Although several recurrent genetic aberrations are known to occur in MALT lymphoma, no comprehensive study on the most prevalent MALT lymphoma-associated genetic aberrations is available. We therefore screened 252 primary MALT lymphomas for translocations t(11;18)(q21;q21), t(14;18)(q32;q21), and t(1;14)(p22;q32), and trisomies 3 and 18. The above-listed translocations occurred mutually exclusively and were detected overall in 13.5, 10.8, and 1.6% of the cases; trisomy 3 and/or 18 occurred in 42.1%. The frequency at which the translocations occurred varied markedly with the primary site of disease. The t(11;18)(q21;q21) was mainly detected in pulmonary and gastric tumors, whereas the t(14;18)(q32;q21) was most commonly found in lesions of the ocular adnexa/orbit, skin, and salivary glands. Trisomies 3 and 18 each occurred most frequently in intestinal and salivary gland MALT lymphomas. Our results demonstrate that the three translocations and trisomies 3 and 18 occur at markedly variable frequencies in MALT lymphoma of different sites.