European recommendations and quality assurance for cytogenomic analysis of haematological neoplasms.

Cytogenomic investigations of haematological neoplasms, including chromosome banding analysis, fluorescence in situ hybridisation (FISH) and microarray analyses have become increasingly important in the clinical management of patients with haematological neoplasms. The widespread implementation of these techniques in genetic diagnostics has highlighted the need for guidance on the essential criteria to follow when providing cytogenomic testing, regardless of choice of methodology. These recommendations provide an updated, practical and easily available document that will assist laboratories in the choice of testing and methodology enabling them to operate within acceptable standards and maintain a quality service.

ALK rearrangements in EBUS-derived transbronchial needle aspiration cytology in lung cancer.

OBJECTIVES: Patients with non-small cell lung cancer (NSCLC) positive for anaplastic lymphoma kinase (ALK) gene rearrangements may be treated successfully with the ALK inhibitor crizotinib. ALK copy-number abnormalities have also been described. In this study, we evaluated the suitability of fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) to determine ALK status in endobronchial ultrasound (EBUS)-derived cytology samples. METHODS: Samples were obtained from 55 consecutive patients with NSCLC who had undergone EBUS-transbronchial needle aspiration (TBNA) according to our standard clinical protocols. All tumours had been screened previously for epithelial growth factor receptor (EGFR) and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations. FISH, using commercially available ALK rearrangement-specific probes, was employed to assess ALK status. IHC using the ALK-1 monoclonal antibody (DAKO) was also performed. RESULTS: FISH analysis was successful in 52 of 55 samples (94.5%); ALK rearrangement was demonstrated in 3 of 52 samples from patients with NSCLC (5.7%). ALK amplification was observed in 3 of 52 patient samples (5.7%) and an increase in ALK copy number was found in 28 of 52 patient samples (53.8%). IHC on cell blocks demonstrated ALK expression in one of three samples with ALK rearrangement. One patient sample had concomitant ALK rearrangement and KRAS mutation. CONCLUSIONS: We found FISH to be superior to IHC using the ALK-1 monoclonal antibody for the detection of ALK rearrangement in EBUS-TBNA cytology specimens in NSCLC, and also that ALK rearrangement can co-exist with KRAS mutation in the same tumour.

Drosophila Ndfip is a novel regulator of Notch signaling.

In the Drosophila wing, the Nedd4 ubiquitin ligases (E3s), dNedd4 and Su(dx), are important negative regulators of Notch signaling; they ubiquitinate Notch, promoting its endocytosis and turnover. Here, we show that Drosophila Nedd4 family interacting protein (dNdfip) interacts with the Drosophila Nedd4-like E3s. dNdfip expression dramatically enhances dNedd4 and Su(dx)-mediated wing phenotypes and further disrupts Notch signaling. dNdfip colocalizes with Notch in wing imaginal discs and with the late endosomal marker Rab7 in cultured cells. In addition, dNdfip expression in the wing leads to ectopic Notch signaling. Supporting this, expression of dNdfip suppressed Notch(+/-) wing phenotype and knockdown of dNdfip enhanced the Notch(+/-) wing phenotype. The increase in Notch activity by dNdfip is ligand independent as dNdfip expression also suppressed deltex RNAi and Serrate(+/-) wing phenotypes. The opposing effects of dNdfip expression on Notch signaling and its late endosomal localization support a model whereby dNdfip promotes localization of Notch to the limiting membrane of late endosomes allowing for activation, similar to the model previously shown with ectopic Deltex expression. When dNedd4 or Su(dx) are also present, dNdfip promotes their activity in Notch ubiquitination and internalization to the lysosomal lumen for degradation.

Recent advances into understanding some aspects of the structure and function of mammalian and avian lungs.

Recent findings are reported about certain aspects of the structure and function of the mammalian and avian lungs that include (a) the architecture of the air capillaries (ACs) and the blood capillaries (BCs); (b) the pulmonary blood capillary circulatory dynamics; (c) the adaptive molecular, cellular, biochemical, compositional, and developmental characteristics of the surfactant system; (d) the mechanisms of the translocation of fine and ultrafine particles across the airway epithelial barrier; and (e) the particle-cell interactions in the pulmonary airways. In the lung of the Muscovy duck Cairina moschata, at least, the ACs are rotund structures that are interconnected by narrow cylindrical sections, while the BCs comprise segments that are almost as long as they are wide. In contrast to the mammalian pulmonary BCs, which are highly compliant, those of birds practically behave like rigid tubes. Diving pressure has been a very powerful directional selection force that has influenced phenotypic changes in surfactant composition and function in lungs of marine mammals. After nanosized particulates are deposited on the respiratory tract of healthy human subjects, some reach organs such as the brain with potentially serious health implications. Finally, in the mammalian lung, dendritic cells of the pulmonary airways are powerful agents in engulfing deposited particles, and in birds, macrophages and erythrocytes are ardent phagocytizing cellular agents. The morphology of the lung that allows it to perform different functions-including gas exchange, ventilation of the lung by being compliant, defense, and secretion of important pharmacological factors-is reflected in its "compromise design."

Molecular characterisation of the t(1;15)(p22;q22) translocation in the prostate cancer cell line LNCaP.

Although chromosome translocations are well-documented recurrent events in hematological malignancies and soft tissue sarcomas, their significance in carcinomas is less clear. We report here the molecular characterization of the reciprocal translocation t(1;15)(p22;q22) in the prostate carcinoma cell line, LNCaP. The chromosome 1 breakpoint was localized to a single BAC clone, RP11-290M5, by sequential FISH analysis of clones selected from the NCBI chromosome 1 map. This was further refined to a 580-bp region by Southern blot analysis. A 2.85-kb fragment spanning the der(1) breakpoint was amplified by long-range inverse PCR. The breakpoint on chromosome 1 was shown to lie between the CYR61 and the DDAH1 genes with the der(1) junctional sequence linking the CYR61 gene to the TSPAN3 (TM4SF8) gene on chromosome 15. Confirmatory PCR and FISH mapping of the der(15) showed loss of chromosome material proximal to the breakpoint on chromosome 15, containing the PSTPIP1 and RCN2 genes. On the available evidence we conclude that this translocation does not result in an in-frame gene fusion. Comparative expressed sequence hybridization (CESH) and comparative genomic hybridization (CGH) analysis, showed relative down-regulation of gene expression surrounding the breakpoint, but no gross change in genomic copy number. Real-time quantitative RT-PCR for genes around the breakpoint supported the CESH data. Therefore, here we may have revealed a gene down-regulation mechanism associated with a chromosome translocation, either through small deletion at the breakpoint or through another means of chromosome domain related gene regulation.

Prognostic factors for patients with chronic myeloid leukaemia in chronic phase treated with imatinib mesylate after failure of interferon alfa.

We assessed clinical results in 145 patients with chronic myeloid leukaemia in chronic phase who satisfied criteria for interferon-alpha failure and were thus eligible for treatment with imatinib at the Hammersmith Hospital. We used univariate and multivariate analyses to develop a risk score based on features defined after treatment for 3 months. We identified a low neutrophil count and poor cytogenetic response (<35% Ph-negative marrow metaphases) at 3 months as principal independent predictive factors and incorporated them into a three-tier prognostic scoring system for individual patients. For patients in the low-, intermediate- and high-risk groups, the probabilities of survival at 24 months were 100, 82 and 40% (P<0.0001) and progression-free survival 100, 66 and 15% (P<0.0001), respectively. This Hammersmith prognostic scoring system was validated with an independent cohort of patients treated at another UK centre.

Autoimmune cytopenias in the 22q11.2 deletion syndrome.

We describe two cases of recurrent autoimmune cytopenias, which were subsequently diagnosed with a 22q11.2 deletion/DiGeorge syndrome. The cases are of particular interest as both possessed limited clinical features of this syndrome, and the investigation of haematological abnormalities led to the establishment of a definitive genetic diagnosis.

Genetic susceptibility to Hodgkin's disease and secondary neoplasias: FISH analysis reveals patients at high risk of developing secondary neoplasia.

BACKGROUND: Cytotoxic drugs administered before high-dose therapy (HDT) represent a significant factor in the development of leukemic complications in patients with lymphoid malignancies. This retrospective study was used to detect evidence of abnormal therapy-related myelodysplasia/secondary acute myeloid leukaemia (tMDS/sAML) clones before HDT in a subset of patients who subsequently developed secondary neoplasia. PATIENTS AND METHODS: 230 patients with non-Hodgkin's lymphoma (NHL) underwent HDT comprising cyclophosphamide and total body irradiation (TBI) with autologous hematopoietic progenitor-cell support. Thirty-three patients have developed tMDS/sAML and 20 of these were screened for the presence of emerging therapy-related abnormalities before HDT. A further 24 patients without evidence of secondary neoplasia were screened using fluorescence in situ hybridisation (FISH). RESULTS: Significant levels of abnormal cells were identified in 20/20 patients screened who have developed secondary neoplasia compared with only three of 24 patients in the HDT control group who have not. The latter three patients have since died. CONCLUSIONS: The triple FISH assay was developed to detect loss of chromosomal material from 5q31, 7q22 and 13q14. It can potentially identify those patients at risk of alkylating agent-induced leukaemia before they proceed to HDT. Used in a prospective manner, the triple FISH assay could permit more informed clinical management.

The characterisation of the lymphoma cell line U937, using comparative genomic hybridisation and multi-plex FISH.

The cell line U937, which has been used extensively for studies of myeloid differentiation, bears the t(10;11)(p13;q14) translocation which results in a fusion between the MLLT10 (myeloid/lymphoid or mixed-lineage leukemia [trithorax, Drosophila, homolog]; translocated to 10; alias AF10) gene and the Ap-3-like clathrin assembly protein, PICALM (Clathrin assembly lymphoid myeloid leukaemia). Apart from this translocation, very little is known about the other genetic alterations in this cell line that may represent significant events in disease progression. In this study, conventional G-banding, CGH and M-FISH have been used to characterise fully all of the cytogenetic alterations present in the U937 cell line. M-FISH analysis confirmed the presence of the t(10;11) and an apparently normal copy of both chromosomes 10 and 11. A t(1;5) translocation was observed as well as several unbalanced rearrangements. CGH detected amplifications resulting from duplications of 2q, 6p and 13q. These changes could result in fusion gene products involved in carcinogenesis or the positions of putative oncogenes and tumour suppressor genes. A good correlation between conventional G-banding, CGH and M-FISH was observed.

Localisation of a novel region of recurrent amplification in follicular lymphoma to an approximately 6.8 Mb region of 13q32-33.

Follicular lymphoma (FL) is characterised by the presence of the t(14;18)(q32;q21) and represents approximately 25% of new cases of non-Hodgkin's lymphoma. While the t(14;18) is a well-documented rearrangement, the role of secondary cytogenetic abnormalities in the development and progression of these tumours remains unclear. Comparative genomic hybridisation was used to characterise changes in DNA copy number in tumour DNA from patients with this malignancy. The mean numbers of deletion and amplification events found in each of the 45 samples studied were 1.8 and 2.3, respectively. Regions of recurrent (>10% tumour samples) gain involved chromosomes 2p13-16 (16%), 7 (20%), 12 (16%), 13q21-33 (18%), 18 (27%), and X (36%) and frequent losses localised to 6q (29%) and 17p (20%). Amplification of chromosome 13 represents a novel finding in FL. The minimal amplified region was refined to a 6.8-Mb interval of 13q32-33 between the BAC clones 88K16 and 44H20 by fluorescence in situ hybridisation studies using metaphase chromosomes derived from tumour material. There are a number of reports in the literature suggesting that amplification of chromosome 13 also occurs in other human cancers. The location of the putative oncogene on 13q described here in follicular and transformed lymphoma may also be important in the evolution of many other malignancies.

Detection of chromosome abnormalities pre-high-dose treatment in patients developing therapy-related myelodysplasia and secondary acute myelogenous leukemia after treatment for non-Hodgkin's lymphoma.

PURPOSE: To assess whether pre-high-dose therapy (HDT)-related factors play a critical role in the development of therapy-related myelodysplasia (tMDS) or secondary acute myelogenous leukemia (sAML). PATIENTS AND METHODS: Twenty-nine of 230 patients with a primary diagnosis of non-Hodgkin's lymphoma (NHL) developed tMDS/sAML after HDT comprising cyclophosphamide and total-body irradiation (TBI) supported by autologous hematopoietic progenitor cells. G-banding and fluorescence in-situ hybridization (FISH) were used to detect clonal cytogenetic abnormalities. RESULTS: The majority of patients showed complex karyotypes at diagnosis of tMDS/sAML containing, in particular, complete or partial loss of chromosomes 5 and/or 7. Using single locus-specific FISH probes, significant levels of clonally abnormal cells were found before HDT in 20 of 20 tMDS/sAML patients screened, compared with three of 24 patients screened who currently have not developed tMDS/sAML, at a median follow-up of 5.9 years after HDT. CONCLUSION: Prior cytotoxic therapy may play an important etiologic role and may predispose to the development of tMDS/sAML. Using a triple FISH assay designed to detect loss of chromosomal material from 5q31, 7q22, or 13q14, significant levels of abnormal cells can be detected before HDT and may predict which patients are at increased risk of developing secondary disease. Further prospective evaluation of this FISH assay is warranted to determine its predictive power in this setting.

The most frequent constitutional translocation in humans, the t(11;22)(q23;q11) is due to a highly specific alu-mediated recombination.

The t(11;22) is the most common recurrent non-Robertsonian constitutional translocation in humans, having been reported in more than 160 unrelated families. Balanced carriers are at risk of having offspring with the derivative 22 syndrome owing to 3:1 meiotic non-disjunction event. Clinical features of the der(22) syndrome include mental retardation, craniofacial abnormalities and congenital heart defects. The breakpoints for the t(11;22) translocation have been mapped to specific Alu repeats on chromosomes 11 and 22, indicating that this event is due to an Alu-Alu recombination. Remarkably, in five samples derived from individuals with no apparent common ancestry the der(11) and der(22) breakpoints appear to be almost identical at the genomic sequence level. The small number of base differences between the samples indicates some variation in the position of the breakpoints, although this appears to be quite limited. Indeed, the der(11) breakpoints are all located within a region of just 32 bp and the der(22) breakpoints within 21 bp. If, as suggested by current data, the widespread occurrence of this translocation is due to multiple independent events, our results suggest that this particular Alu-Alu recombination is subject to an unprecedented degree of selection.

Novel mutations and polymorphisms in the Fanconi anemia group C gene.

Fanconi anemia (FA) is an autosomal recessive disorder associated with hypersensitivity to DNA cross-linking agents and bone marrow failure. At least four complementation groups have been defined, and the FA group C gene (FAC) has been cloned. We have screened 76 unrelated FA patients of diverse ethnic and geographic origins and from unknown complementation groups for mutations in the FAC gene either by chemical cleavage mismatch analysis or by single-strand conformational polymorphism (SSCP). Five mutations were detected in four patients (5.3%), including two novel mutations (W22X and L496R). Nine polymorphisms were detected, seven of which have not been described previously (663A-->G, L190F, IVS6 + 30C-->T, I312V, V449M, Q465R, and 1974G-->A). Six of the nine polymorphisms occurred in patients or controls from the Tswana or Sotho chiefdoms of South Africa and were not found in 50 unrelated European controls. Restriction site assays were established for all 8 pathogenic mutations identified in the FAC gene to date and used to screen a total of 94 unrelated FA patients. This identified only one other group C patient, who was homozygons for the mutation IVS4 + 4A-->T. This study indicates that the proportion of FA patients from complementation group C is generally likely to be less than 10%. Guidelines for the selection of FA patients for FAC mutation screening are proposed.