Translocation t(2;7)(p12;q21-22) with dysregulation of the CDK6 gene mapping to 7q21-22 in a non-Hodgkin’s lymphoma with leukemia

Background and Objectives. A female patient presented with splenomegaly and lymphocytosis with atypical lymphoid cell morphology, We identified t(2;7)(p12;q21) prompting studies of the translocation breakpoint and its consequences on protein expression to confirm or otherwise the recently reported involvement of CDK6 and IG kappa genes in the t(2;7) leading to over-expression of CDK6 protein. Design and Methods. A variety of clinical and laboratory techniques including cell marker, cytogenetic and histologic studies were applied in order to establish the diagnosis. Fluorescence in situ hybridization (FISH) and Southern blotting were used for mapping the translocation breakpoint and Western blotting for assessing protein expression. Results. Immunophenotyping showed the presence of a B-cell population with strong expression of FMC7, CD22, CD79b, CD5 and K restricted surface immunoglobulins. Based on morphology and immunophenotypic markers the diagnosis of B-cell nonHodgkin’s lymphoma was made. Karyotyping revealed a clone with t(2;7)(p12;q21-22). Evidence for clonal evolution with additional abnormalities including a deletion of the TP53 was present, We established by FISH and Southern blotting that the breakpoint on 7q21-22 fell in a region 66kb telomeric to the previously reported breakpoint for the t(2;7) and was the same as that observed in a t(7;21). CDK6 protein was over-expressed. The patient received alkylating agents and splenectomy and is alive but the lymphocytosis persists with evidence of disease progression. Interpretations and Conclusions. We have demonstrated that CDK6 expression is dysregulated even when the breakpoint on 7q21-22 is located 66kb upstream from the coding region. Interestingly, the precise assignment of the lymphoma type in our case was not possible even when the splenic histology was analyzed. (C)2002, Ferrata Storti Foundation

Receptor and secreted targets of Wnt-1/β-catenin signalling in mouse mammary epithelial cells

BACKGROUND: Deregulation of the Wnt/ β-catenin signal transduction pathway has been implicated in the pathogenesis of tumours in the mammary gland, colon and other tissues. Mutations in components of this pathway result in β-catenin stabilization and accumulation, and the aberrant modulation of β-catenin/TCF target genes. Such alterations in the cellular transcriptional profile are believed to underlie the pathogenesis of these cancers. We have sought to identify novel target genes of this pathway in mouse mammary epithelial cells. METHODS: Gene expression microarray analysis of mouse mammary epithelial cells inducibly expressing a constitutively active mutant of β-catenin was used to identify target genes of this pathway. RESULTS: The differential expression in response to ΔNβ-catenin for five putative target genes, Autotaxin, Extracellular Matrix Protein 1 (Ecm1), CD14, Hypoxia-inducible gene 2 (Hig2) and Receptor Activity Modifying Protein 3 (RAMP3), was independently validated by northern blotting. Each of these genes encodes either a receptor or a secreted protein, modulation of which may underlie the interactions between Wnt/β-catenin tumour cells and between the tumour and its microenvironment. One of these genes, Hig2, previously shown to be induced by both hypoxia and glucose deprivation in human cervical carcinoma cells, was strongly repressed upon ΔNβ-catenin induction. The predicted N-terminus of Hig2 contains a putative signal peptide suggesting it might be secreted. Consistent with this, a Hig2-EGFP fusion protein was able to enter the secretory pathway and was detected in conditioned medium. Mutation of critical residues in the putative signal sequence abolished its secretion. The expression of human HIG2 was examined in a panel of human tumours and was found to be significantly downregulated in kidney tumours compared to normal adjacent tissue. CONCLUSIONS: HIG2 represents a novel non-cell autonomous target of the Wnt pathway which is potentially involved in human cancer

Molecular Characterization of the Region 7q22.1 in Splenic Marginal Zone Lymphomas

Splenic marginal zone lymphomas (SMZL) are an uncommon type of B-cell non-Hodgkin's lymphoma (NHL-B) in which no specific chromosomal translocations have been described. In contrast, the most frequent cytogenetic abnormality is the loss of the long arm of chromosome 7 (7q). Previous reports have located this loss in the 7q32 region. In order to better characterize the genomic imbalances in SMZL, molecular studies were carried out in 73 patients with SMZL. To gain insight into the mapping at 7q a tiling array was also used. The results confirmed the loss of 7q as the most frequent change. In addition, several abnormalities, including 4q22.1, 1q21.3–q22, 6q25.3, 20q13.33, 3q28, 2q23.3–q24.1 and 17p13, were also present. A loss of 7q22.1 at 99925039–101348479 bp was observed in half of the cases. The region of 7q22.1 has not previously been characterised in SMZL. Our results confirmed the presence of a new region of loss on chromosome 7 in these NHL

The genetic characterisation of splenic lymphoma with villous lymphocytes

Available from British Library Document Supply Centre- DSC:DXN057488 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Polycythemia vera: analysis of DNA from blood granulocytes using comparative genomic hybridization

Polycythemia vera: analysis of DNA from blood granulocytes using comparative genomic hybridization. Background and Objectives. The diagnosis of polycythemia vera (PV) is supported by the finding of an abnormal karyotype in patients with erythrocytosis. However, most W patients have normal marrow cytogenetics at presentation and there is reluctance to use this test routinely. Comparative genomic hybridization (CGH) is a cytogenetic screening technique that analyzes interphase cells. This approach offers practical advantages over conventional cytogenetics and interphase fluorescence insitu hybridization (IFISH), We have therefore evaluated the diagnostic utility of CGH applied to blood granulocytes in W. Design and Methods. Blood granulocytes from 17 PV patients were analyzed using CGH and the results compared with those from previous conventional cytogenetics and IFISH studies. Results. Three patients had abnormal CGH profiles. One case had gain of 9p. This patient had normal IFISH results using a centromere-g probe. The second case had complete gain of chromosomes 8 and 9 and the third had complete gain of chromosome 9, all confirmed by IFISH. Cytogenetics had not been performed in two of these cases and had failed in the third. Three cases with 20q deletion according to cytogenetics and/or IFISH, were normal by CGH. The remaining subjects were normal by all methods, Interpretation and Conclusions. CGH analysis of blood granulocytes can detect the chromosome gains commonly observed in PV. However, CGH cannot be relied on to detect 20q deletions, which are the most frequent cytogenetic abnormality in W. Thus, CGH has a role in the diagnosis and follow-up of W patients, but must be used in conjunction with other methods

p53 abnormalities in splenic lymphoma with villous lymphocytes

The incidence and role of p53 abnormalities have not been reported in splenic lymphoma with villous lymphocytes (SLVL), the leukemic counterpart of splenic marginal zone lymphoma. Because p53 abnormalities correlate with progressive and refractory disease in cancer and isochromosome 17q has been described in SLVL, a low-grade lymphoma that behaves aggressively in a minority of patients, this study investigated p53 changes by molecular and immunophenotypic methods in sample

Prognostic features of splenic lymphoma with villous lymphocytes: a report on 129 patients

Splenic lymphoma with villous lymphocytes (SLVL) is a low-grade B-cell lymphoma defined in the World Health Organization classification as the leukaemic form of splenic marginal zone lymphoma. Presenting features and response to therapy have been described, but information on prognostic factors is scanty. Clinical, laboratory and follow-up data were collected on 129 patients with SLVL to determine features predicting disease behaviour and survival. Diagnosis was made on clinical, morphological and immunophenotypic features and, where available, bone marrow and spleen histology. Median age was 69 years (range 39-90 years) and male:female ratio, 0.9. The majority had splenomegaly, but lymphadenopathy and hepatomegaly were rare. Median Hb was 11.8 g/dl, white blood cell count was 16 x 10(9)/l and platelet count was 145 x 10(9)/l; 27% of patients had monoclonal protein in serum and/or urine. While 27% of patients remained untreated, 10% transformed to high-grade lymphoma. Median follow-up was 61 months and median survival was 13 years, with 72% of patients alive at 5 years. Cox regression analysis showed that increasing age, anaemia, thrombocytopenia and lymphocytosis > 16 x 10(9)/l were independent adverse predictors of overall survival. However, only anaemia and lymphocytosis > 16 x 10(9)/l remained highly significant independent prognostic factors when only deaths due to lymphoma were analysed. Splenectomized patients fared better than those receiving chemotherapy only (P = 0.001 for SLVL deaths). We conclude that SLVL is mainly a disease of the elderly with a relatively benign course but, when treatment is required, splenectomy is beneficial

A narrow deletion of 7q is common to HCL, and SMZL, but not CLL

To further characterise the genetic background of the two closely related B-lymphocytic malignancies hairy cell leukaemia (HCL), and splenic marginal zone lymphoma (SMZL) we have identified characteristic copy number imbalances by comparative genomic hybridisation (CGH). Based on these findings, areas of special interest were fine mapped, and relevant probes constructed for use in interphase-fluorescence in situ hybridisation (FISH) investigations. Thus, using the CGH data from 52 HCL and 61 SMZL patients, we identified the characteristic profiles of copy number imbalances for both diseases. These were a gain of 5q13-31 (19%) and loss of 7q22-q35 (6%) for HCL, and gain of 3q25 (28%), loss of 7q31 (16%), and gain of 12q15 (16%) for SMZL. A partial loss of 7q unsual for low-malignant B-cell diseases was found to be common to the two diseases. This loss was therefore fine mapped with BAC/PAC clones. Fine mapping revealed that in SMZL the minimal lost region covers 11.4 Mb spanning from 7q31.33 to 7q33 located between sequence tagged site (STS)-markers SHGC-3275 and D7S725. This area was distinct from the commonly deleted 7q region of myelodysplastic syndrome/acute myeloid leukaemia (MDS/AML). A FISH probe specific for the 7q region was constructed. Using this probe in an interphase-FISH investigation we showed the minimal lost 7q-region of HCL and SMZL to be one and the same. In one HCL case, this investigation furthermore showed the extent of the deleted region to be below the detection limit of CGH, whereas interphase-FISH screening of 36 chronic lymphocytic leukaemia (CLL) cases showed no deletion of the 7q area. In conclusion, we have identified characteristic profiles of copy number imbalances in HCL and SMZL and fine mapped the minimal extent of a commonly lost 7q area of special interest. We hypothesise that this region may contain (a) gene(s) important for the pathology of HCL and SMZL