Detection by the fluorescence in situ hybridization technique of MYC translocations in paraffin-embedded lymphoma biopsy samples

Worldwide Prevalence of Epstein-Barr Virus in Patients with Burkitt Lymphoma: A Systematic Review and Meta-Analysis

Burkitt lymphoma (BL) is a form of B-cell malignancy that progresses aggressively and is most often seen in children. While Epstein-Barr virus (EBV) is a double-stranded DNA virus that has been linked to a variety of cancers, it can transform B lymphocytes into immortalized cells, as shown in BL. Therefore, the estimated prevalence of EBV in a population may assist in the prediction of whether this population has a high risk of increased BL cases. This systematic review and meta-analysis aimed to estimate the prevalence of Epstein-Barr virus in patients with Burkitt lymphoma. Using the appropriate keywords, four electronic databases were searched. The quality of the included studies was assessed using the Joanna Briggs Institute's critical appraisal tool. The results were reported as percentages with a 95% confidence interval using a random-effects model (CI). PROSPERO was used to register the protocol (CRD42022372293), and 135 studies were included. The prevalence of Epstein-Barr virus in patients with Burkitt lymphoma was 57.5% (95% CI: 51.5 to 63.4, n = 4837). The sensitivity analyses demonstrated consistent results, and 65.2% of studies were of high quality. Egger's test revealed that there was a significant publication bias. EBV was found in a significantly high proportion of BL patients (more than 50% of BL patients). This study recommends EBV testing as an alternative for predictions and the assessment of the clinical disease status of BL.

Analysis of the Diagnosis of Burkitt-Like Lymphoma in a Patient With Atypical Cytogenetics and Molecular Markers

The World Health Organization (WHO) criteria for diagnosis of hematopoietic and lymphoid cancers serve as a useful t­ool for distinguishing between malignant conditions based on phenotypic, morphologic, and/or cytogenetic presentations, but their utility is limited in patients whose diseases contain elements of multiple diagnoses. We present a case of a 59-year-old male with enlargement of muscular and soft tissues of the left hip and an intraconal soft tissue mass surrounding the left optic nerve, who was treated for Burkitt-like lymphoma (BLL). Cytogenetics revealed the absence of an MYC rearrangement involving chromosomes 2, 14, or 22, normally found in Burkitt lymphoma, or the classic telomeric losses and proximal gains observed in BLL. Diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS) and high-grade B-cell lymphoma, not otherwise specified (HGBL, NOS) were also considered as possible diagnoses. The persistence of ambiguous lymphoma diagnoses demonstrates the need for both continued research in the area and regular revision of the WHO criteria. Physicians working with patients with poorly defined lymphomas should defer to diagnostic algorithms where applicable, many of which have been proposed in the literature.

Novel markers in pediatric-type follicular lymphoma

The aim of this study was to review the histopathological, phenotypic, and molecular characteristics of pediatric-type follicular lymphoma (PTFL) and to assess the diagnostic value of novel immunohistochemical markers in distinguishing PTFL from follicular hyperplasia (FH). A total of 13 nodal PTFLs were investigated using immunohistochemistry, fluorescence in situ hybridization (FISH), and PCR and were compared with a further 20 reactive lymph nodes showing FH. Morphologically, PTFL cases exhibited a follicular growth pattern with irregular lymphoid follicles in which the germinal centers were composed of numerous blastoid cells showing a starry-sky appearance. Immunohistochemistry highlighted preserved CD10 (13/13) and BCL6 (13/13) staining, CD20 (13/13) positivity, a K light chain predominance (7/13), and partial BCL2 expression in 6/13 cases (using antibodies 124, E17, and SP66). The germinal center (GC)–associated markers stathmin and LLT-1 were positive in most of the cases (12/13 and 12/13, respectively). Interestingly, FOXP-1 was uniformly positive in PTFL (12/13 cases) in contrast to reactive GCs in FH, where only a few isolated positive cells were observed. FISH revealed no evidence of BCL2, BCL6, or MYC rearrangements in the examined cases. By PCR, clonal immunoglobulin gene rearrangements were detected in 100% of the tested PTFL cases. Our study confirmed the unique morphological and immunophenotypic features of PTFL and suggests that FOXP-1 can represent a novel useful diagnostic marker in the differential diagnosis between PTFL and FH.

A Rare Case of Systemic Adult Burkitt Lymphoma Presenting as Acute Acalculous Cholecystitis

Acute acalculous cholecystitis (AAC) is an uncommon presentation of cholecystitis accounting for 10% of cases. AAC is caused by a localized ischemic event in the gallbladder usually in critically ill patients. Several cases of localized or systemic lymphoma have been described in the literature as causes of AAC. We present a patient with a rare case of AAC due to undiagnosed systemic Burkitt lymphoma. Pathology of the gallbladder revealed Burkitt lymphoma with analysis of his cerebral spinal fluid confirming Stage IV disease. This case report reviews acute acalculous cholecystitis, lymphomas of the gallbladder and extrahepatic duct, and adult Burkitt lymphoma.

Changes in expression of WT1 during induced differentiation of the acute myeloid leukemia cell lines by treatment with 5-aza-2'-deoxycytidine and all-trans retinoic acid

The aim of the present study was to investigate the effect of 5-aza-2'-deoxycytidine (decitabine; DAC) and all-trans retinoic acid (ATRA) on Wilms' tumor 1 (WT1) in acute myeloid leukemia (AML) in vitro. The methylation status of the WT1 promoter was analyzed using methylation-specific polymerase chain reaction (MSP). The expression level of WT1 was detected by reverse transcription-quantitative polymerase chain reaction. The effect of DAC and ATRA on cell differentiation was evaluated by flow cytometry. The WT1 gene was methylated in U937 cells, but unmethylated in SHI-1 and K562 cells; the U937 cells did not express the WT1 gene, but the SHI-1 and K562 cells highly expressed the WT1 gene. DAC and ATRA, alone or in combination, exhibited no effect on the expression level of WT1 in the U937 cells and on the differentiation of the K562 cells. The combined treatment of DAC and ATRA markedly decreased the WT1 expression levels of the SHI-1 and K562 cells, and induced the differentiation of the SHI-1 and U937 cells. In the SHI-1 cells, WT1 expression changed inversely to the dynamic changes of cluster of differentiation 11b-positive rates. In conclusion, the combined treatment of DAC and ATRA has clinical therapeutic potential in acute monocytic leukemia patients with high WT1 expression and a poor response to standard induction chemotherapy.

How I treat Burkitt lymphoma in adults

Burkitt lymphoma (BL) is an aggressive B-cell non-Hodgkin lymphoma that is almost uniformly associated with translocations involving the gene for MYC on chromosome 8. The 3 subtypes of BL, endemic, sporadic, and immunodeficiency-associated, differ from epidemiologic and clinical perspectives but may be genetically similar. Prompt administration of multiagent immunochemotherapy regimens is associated with favorable outcomes for the majority of patients. Survival is inferior in older patients, likely reflecting increased therapy-related toxicity, possibly resulting in decreased treatment intensity. Central nervous system prophylaxis, tumor lysis prevention and treatment, and management of infectious complications from myelosuppressive regimens are critical. Prognosis of refractory or relapsed disease is poor and patients are best treated on clinical trials when available.

[Round robin test for detection of genomic aberrations in non-Hodgkin lymphoma by in situ hybridization]

BACKGROUND

The detection of characteristic genomic aberrations by fluorescence in situ hybridization (FISH) has a high diagnostic impact on lymphomas according to the World Health Organization (WHO). To investigate the reproducibility of non-isotopic ISH results a multicenter trial was carried out involving eight institutes for hematopathology.

MATERIAL AND METHODS

Analyses were performed on two diffuse large B-cell lymphomas (DLBCL) without known aberrations, on one follicular lymphoma with a IGH/BCL2 translocation and BCL6 split and on two B-cell lymphomas intermediate between DLBCL and Burkitt's lymphoma with c-MYC and BCL2 rearrangements, one with an additional BCL6 split. Break-apart probes for BCL6 and c-MYC, as well as fusion probes for the c-MYC/IGH and the IGH/BCL2 translocations were used.

RESULTS

All aberrations were correctly detected by all centres and no false positive or false negative results were obtained. The numbers of positive cells varied from 25% to 94%. Pearson's correlation coefficient between the centres was always > 0.8.

CONCLUSIONS

The ISH analysis of recurrent genomic aberrations in formalin-fixed paraffin-embedded (FFPE) tissue is a highly reproducible technique which yields substantial additive help for lymphoma diagnostics.

Molecular cytogenetics of lymphoma: where do we stand in 2010?

For the past 20 years most malignant lymphomas have been classified as clinicopathological entities, each with its own combination of clinical, morphological, immunophenotypic and molecular genetic characteristics. Molecular and cytogenetic abnormalities can be detected by a wide range of techniques, ranging from conventional karyotyping to single nucleotide polymorphism analysis. In this review, we consider the common genetic abnormalities found in lymphoma and discuss the advantages and disadvantages of individual techniques used in their detection. Finally, we discuss briefly possible novel developments in the field of lymphoma diagnostics.

Fluorescent in situ hybridization heating pretreatment: the key is temperature control

Fluorescent in situ hybridization (FISH) is a very useful tool for diagnostic and prognostic purposes in pathology. However, many laboratories still experience troubles when applying FISH to paraffin material. To overcome these difficulties, different pretreatments which include enzymatic digestion have been described. Usually, previous to digestion, a heating step is performed. The aim of this study was to compare the efficiency of the heating step with different buffers and different heating methods. We conclude that the main factor in the heating pretreatment is the temperature control, irrespective of the buffer used. Best results are obtained with any buffer by heating the slides to 99°C for 15 min followed by 10 min at room temperature.

Oncohematological diseases in the Vale do Paraíba, State of São Paulo: demographic aspects, prevalences and incidences

BACKGROUND

Based on the necessity of detailed information that supports effective strategies to improve cancer outcomes in the different regions of Brazil, the aims of this study were to report demographic aspects and to calculate the prevalence and incidence rates of oncohematological diseases in the region of Vale do Paraíba.

METHODS

This is a multicentric prospective study carried out from October 2009 to March 2010. A total of 500 over 19-year-old patients were enrolled. Data such as type of healthcare insurance, gender, age, ethnic classification, place of residence, schooling, income, body mass index, new cases and the period between the first symptoms and a definite diagnosis were collected. The prevalence and incidence rates were calculated according to an estimated number of 1,319,800 inhabitants.

RESULTS

The prevalence and incidence rates per 100,000 inhabitants in the period of six months were, respectively: acute myeloid leukemia 1.5 and 0.7; acute lymphoblastic leukemia 0.5 and 0.1; chronic lymphocytic leukemia 2.4 and 0.4; chronic myeloid leukemia 6.2 and 0.8; Hodgkin's lymphoma 2.9 and 0.9; non-Hodgkin lymphoma 9.8 and 4.3; multiple myeloma 5.7 and 0.7; myelodysplastic syndromes 2.1 and 0.2 and myeloproliferative syndromes 5.1 and 0.3.

CONCLUSION

Giving the paucity of data in this field of investigation, our data may be useful for comparisons with those of other regions of Brazil and will assist in the implementation of treatment programs of oncohematological diseases in this region.

Perivascular epithelioid cell tumor with SFPQ/PSF-TFE3 gene fusion in a patient with advanced neuroblastoma

We report a case of perivascular epithelioid cell tumor (PEComa) with an SFPQ/PSF-TFE3 gene fusion in a 14-year-old girl treated for adrenal neuroblastoma for 4 years. Imaging studies revealed a tumor in the wall of the sigmoid colon, which was radiologically different from the neuroblastoma, together with several inguinal and cervical lymph node metastases of the neuroblastoma. Microscopically, the tumor in the sigmoid colon showed sheet-like growth of epithelioid cells with abundant clear cytoplasm and round nuclei, which were separated by thin fibrovascular septa. These epithelioid cells were immunohistochemically positive for vimentin, gp100 (detected with monoclonal antibody HMB-45), and TFE3, and the tumor was diagnosed as PEComa. In a fluorescence in situ hybridization assay using an in-house probe for TFE3, the tumor cells showed split signals, indicating a rearrangement of TFE3. Molecular cloning using 5' rapid amplification of complementary DNA ends and subsequent reverse transcription-polymerase chain reaction revealed an SFPQ/PSF-TFE3 gene fusion. To the best of our knowledge, this is the second reported case of metachronous PEComa subsequent to a primary tumor, and the first report confirming an SFPQ/PSF-TFE3 gene fusion in PEComa.

The critical role of histology in an era of genomics and proteomics: a commentary and reflection

The role of histologic examination in lymphoma diagnosis has been called into question by proponents of new technologies, such as genomics and proteomics. We review the history and salient features of morphologic evaluation in lymphoid diseases, and discuss the general and specific limitations of mature ancillary techniques, such as immunohistochemistry, flow cytometry, and molecular studies. We then speculate on the future relationship between morphology and the new genomic and proteomic technologies as they become integrated into clinical practice.

Detection of genetic alterations by immunoFISH analysis of whole cells extracted from routine biopsy material

The detection of genetic abnormalities (eg, translocations, amplifications) in paraffin-embedded samples by the fluorescence in situ hybridization (FISH) technique is usually performed on tissue sections. FISH analysis of nuclei extracted from paraffin-embedded samples is also possible, but the technique is not widely used, principally because of the extra labor involved and the loss of information on tissue architecture. In this article, we report that nuclei extracted from paraffin-embedded tissue often retain at least part of the surrounding cytoplasm. Consequently, immunocytochemical labeling for a range of cellular markers (eg, of lineage or proliferation) can be performed in combination with FISH labeling, allowing specific cell populations to be analyzed for genetic abnormalities. These cell preparations are largely free of the problems associated with tissue sections (eg, truncation artifact, signals in different focal planes) so that interpretation is easy and numerical chromosomal abnormalities are readily assessed. Cells isolated from paraffin sections can be stored in suspension so that arrays can be created as and when needed from a range of neoplasms for investigation by the immunoFISH technique (for example, for studying a new genetic abnormality). This procedure represents a novel methodology, which in some settings offers clear advantages over analysis of tissue sections.

Identification of bone marrow derived nonhematopoietic cells by double labeling with immunohistochemistry and in situ hybridization

Stem cell migration/trafficking is a field of interest that is shared by pathologists, histologists, clinical transplantation teams, cardiologists, neurologists, and many other members of different disciplines. Until the findings of a successful combination of in situ methods, the origin of chimeric parenchymal cells was a dilemma. These doublelabeling techniques have brought insight to our new concept of stem cell biology. It has been extremely helpful in the detection of the origin of terminally differentiated, including hematopoietic and nonhematopoietic, cells appearing following allogeneic stem cell transplantation. It has also become a standard approach for evaluation of repopulation following tissue injury in solid organ transplant patients or experimental models. Although very useful, this technique has its advantages and pitfalls. It requires expertise in application and interpretation. Suitable selection of specific markers against parenchymal cells and preferably a cocktail of antibodies targeting infiltrating inflammatory cells are mandatory. One pitfall of this method is its restriction to sex-mismatched pairs. The spectrum of labels for X and Y chromosomes are suitable for combination. To prevent misinterpretation, the precautions needed are defined in this chapter.

[Optimized protocols for interphase FISH analysis of imprints and sections using split signal probes]

Fluorescent in situ hybridization (FISH) analysis is a molecular technique allowing the detection of recurrent translocations in cancer. Several hybridization protocols were assayed in order to evaluate their performances for interphase FISH analysis of histological sections and imprints using split probes. Adult and foetal lymphoid tissues were selected. Touch imprints of fresh (EF) or frozen (EC) tissues, sections (CF) and isolated nuclei (NI) of formol-fixed paraffin-embedded tissues were performed. The cut-off values of the IGH, IGlambda, BCL-2, BCL-6, CCND1 and MYC DNA FISH split signal probes were calculated for adult reactive lymph nodes on the different histological preparations (EC, CF, CC, NI) and on several tissues for the IGH and BCL-6 probes. In reactive lymph nodes, the cut-off values of the probes were between 3 and 13% and found independent of the preparation type. Conversely, slight but significant variations of the cut-off level were observed when different foetal control tissues were assayed with the same probe set. Finally, this study provided optimized-protocols for FISH analysis of either fresh/frozen imprints or formalin-fixed paraffin-embedded sections using split signal DNA probes.

The specificity of interphase FISH translocation probes in formalin fixed paraffin embedded tissue sections is readily assessed using automated staining and scoring of tissue microarrays constructed from murine xenografts

Implementation of interphase fluorescence in situ hybridization (FISH) assays in the clinical laboratory requires validation against established methods. Validation tools in common use include exchange of consecutive sections with another institution that has already established the FISH assay, comparison with conventional banded metaphase cytogenetics, confirmation of specificity using probed normal metaphases, consecutive paraffin sections of a validation set tested by a reference laboratory, and specificity assessment against well characterized cell lines. We have investigated the feasibility of using tissue microarrays (TMA) constructed from murine xenografts as a preliminary specificity-screening tool for validation of interphase FISH assays. Cell lines currently in use for FISH controls are used to generate xenografts in SCID mice which are fixed in formalin and paraffin embedded. A TMA is constructed using duplicate donor cores from the xenograft blocks. Xenografts used represent a wide range of translocations used routinely for formalin fixed paraffin embedded sections evaluated by FISH. Probe cocktails (Abbott-Vysis), for several non-random translocations associated with hematologic neoplasms and soft tissue sarcomas have been used in this manner. On-line deparaffinization, cell conditioning, and prehybridization steps are automated using a staining workstation (Ventana Discovery XT); hybridization and stringency washes are performed manually offline. FISH-probed TMAs are tracked using a Metasystems image scanner and analyzed using classifiers specifically developed for each molecular abnormality. FISH results for each xenograft in the TMA correspond exactly to the genotype previously established for the parent cell line from which the xenograft was prepared. Moderate complexity tissue microarrays constructed from murine xenografts are excellent validation tools for initial assessment of interphase FISH probe specificity.

FISH analysis for the detection of lymphoma-associated chromosomal abnormalities in routine paraffin-embedded tissue

Over the last decade, fluorescence in situ hybridization (FISH) has become a firmly established technique in the diagnosis and assessment of lymphoid malignancies. However, this technique is not wide-ly used in the routine diagnostic evaluation of paraffin-embedded biopsies, most likely because of a perception that it is technically more demanding. There are also uncertainties regarding diagnostic thresholds and the way in which results should be interpreted. In this Review, we describe practical strategies for using FISH analysis to detect lymphoma-associated chromosomal abnormalities in routine paraffin-embedded lymphoma biopsies. Furthermore, we provide proposals on how FISH results should be interpreted (including how to calculate cutoff levels for FISH probes), recorded, and reported. An online appendix (available at http://jmd.amjpathol.org) details various simple, yet robust procedures for paraffin FISH analysis; it also provides additional information on the production of FISH probes, evaluating and reporting FISH results, sources for reagents and equipment, and troubleshooting. We hope that these suggestions will make FISH technology for the study of lymphoma biopsies more accessible to routine diagnostic and research laboratories.

Novel FISH probes designed to detect IGK-MYC and IGL-MYC rearrangements in B-cell lineage malignancy identify a new breakpoint cluster region designated BVR2

Detection of translocations involving MYC at 8q24.1 in B-cell lineage malignancies (BCL) is important for diagnostic and prognostic purposes. However, routine detection of MYC translocations is often hampered by the wide variation in breakpoint location within the MYC region, particularly when a gene other than IGH, such as IGK or IGL, is involved. To address this issue, we developed and validated four fluorescence in situ hybridization (FISH) probes: two break apart probes to detect IGK and IGL translocations, and two dual-color, dual-fusion FISH (D-FISH) probes to detect IGK-MYC and IGL-MYC. MYC rearrangements (four IGK-MYC, 12 IGL-MYC and four unknown partner gene-MYC) were correctly identified in 20 of 20 archival BCL specimens known to have MYC rearrangements not involving IGH. Seven specimens, all of which lacked MYC rearrangements using a commercial IGH/MYC D-FISH probe, were found to have 8q24 breakpoints within a cluster region >350-645 kb 3' from MYC, provisionally designated as Burkitt variant rearrangement region 2 (BVR2). FISH is a useful ancillary tool in identifying MYC rearrangements. In light of the discovery of the distally located BVR2 breakpoint cluster region, it is important to use MYC FISH probes that cover a breakpoint region at least 1.0 Mb 3' of MYC.

Lack of BIC and microRNA miR-155 expression in primary cases of Burkitt lymphoma

We previously demonstrated high expression of primary-microRNA BIC (pri-miR-155) in Hodgkin lymphoma (HL) and lack of expression in most non-Hodgkin lymphoma subtypes including some Burkitt lymphoma (BL) cases. Recently, high expression of BIC was reported in BL in comparison to pediatric leukemia and normal peripheral-blood samples. In this study, we extended our series of BL cases and cell lines to examine expression of BIC using RNA in situ hybridization (ISH) and quantitative RT-PCR (qRT-PCR) and of miR-155 using Northern blotting. Both BIC RNA ISH and qRT-PCR revealed no or low levels of BIC in 25 BL tissue samples [including 7 Epstein-Barr virus (EBV)-positive cases] compared to HL and normal controls. In agreement with these findings, no miR-155 was observed in BL tissues. EBV-negative and EBV latency type I BL cell lines also showed very low BIC and miR-155 expression levels as compared to HL cell lines. Higher levels of BIC and miR-155 were detected in in vitro transformed lymphoblastoid EBV latency type III BL cell lines. An association of latency type III infection and induction of BIC was supported by consistent expression of BIC in 11 and miR-155 in 2 posttransplantation lymphoproliferative disorder (PTLD) cases. In summary, we demonstrated that expression of BIC and miR-155 is not a common finding in BL. Expression of BIC and miR-155 in 3 latency type III EBV-positive BL cell lines and in all primary PTLD cases suggests a possible role for EBV latency type III specific proteins in the induction of BIC expression.

Targeting NF-κB in hematologic malignancies

The transcription factor nuclear factor kappa B (NF-kappaB) can intervene in oncogenesis by virtue of its capacity to regulate the expression of a plethora of genes that modulate apoptosis, and cell survival as well as proliferation, inflammation, tumor metastasis and angiogenesis. Different reports demonstrate the intrinsic activation of NF-kappaB in lymphoid and myeloid malignancies, including preneoplastic conditions such as myelodysplastic syndromes, underscoring its implication in malignant transformation. Targeting intrinsic NF-kappaB activation, as well as its upstream and downstream regulators, may hence constitute an additional approach to the oncologist's armamentarium. Several small inhibitors of the NF-kappaB-activatory kinase IkappaB kinase, of the proteasome, or of the DNA binding of NF-kappaB subunits are under intensive investigation. Currently used cytotoxic agents can induce NF-kappaB activation as an unwarranted side effect, which confers apoptosis suppression and hence resistance to these drugs. Thus, NF-kappaB inhibitory molecules may be clinically useful, either as single therapeutic agents or in combination with classical chemotherapeutic agents, for the treatment of hematological malignancies.

Molecular biology of lymphoma in the microarray era

This review will focus on the molecular biology of lymphoproliferative disorders with emphasis on lymphomas. The spectrum of known recurrent gene rearrangements found in lymphomas will be outlined and their relevance to diagnosis and subclassification of disease will be discussed. Finally, a survey of the current trends in gene expression profiling of lymphomas by microarray technology will be presented with reference to implications for diagnosis, classification, prognosis and treatment.

Lymphoma associated chromosomal abnormalities can easily be detected by FISH on tissue imprints. An underused diagnostic alternative

BACKGROUND

Fluorescence in situ hybridisation (FISH) is useful for detecting specific chromosomal abnormalities in various tumours. In lymphomas, diagnosis is frequently made using paraffin wax embedded tissue. However, FISH performed under these conditions presents potential technical problems and difficulties in interpretation.

AIMS

To show that FISH using tissue imprints and cytopreps or alternatively, bone marrow (BM) smears, constitutes an easy and rapid strategy to overcome these constraints.

METHODS

The study comprised 46 patients with lymphoma. Sixty nine tissue imprints, cytopreps, or BM smears were analysed by FISH. Dual colour, dual fusion FISH probes were used to detect the t(8;14), t(11;14), and t(14;18) translocations, whereas a dual colour breakapart FISH probe was used to detect chromosomal translocations involving the BCL6 gene.

RESULTS

Tissue imprints and cytopreps were successfully hybridised in all 52 cases, whereas hybridisation was successful in 16 of 17 archival BM smears. All patients could be analysed to identify either the presence or absence of chromosomal translocations.

CONCLUSIONS

The use of tissue imprints, cytopreps, or BM smears to identify chromosomal abnormalities by FISH is a rapid and useful ancillary approach for diagnostic purposes. Therefore, it could be used on a routine basis whenever fresh samples are available.

Best Practice No 185. Cytological and molecular diagnosis of lymphoma

With the advances in molecular pathology, the cell as a morphological and functional unit has become essential in the diagnosis of lymphoma. Conventional staining, preparation, and interpretation of cells, as seen in fine needle aspiration cytology (FNAC), often used as a first line investigation of lymphadenopathy, is being supplemented with an array of immunocytochemical and molecular analyses, aimed not only at a more precise disease definition, but also at recognising factors that can predict prognosis and response to treatment. Accepting the pitfalls of conventional cytomorphology, this review looks at molecular changes characteristic to particular lymphomas and explores the currently available technology for their detection, with particular reference to cytological material. Future protocols for the diagnosis and management of patients with lymphadenopathy should include FNAC as an initial investigation, followed by immunocytochemistry and molecular investigations. Tissue biopsy, the conventional method of diagnosis, may be avoided in selected cases.

Immunoglobulin gene analysis reveals 2 distinct cells of origin for EBV-positive and EBV-negative Burkitt lymphomas

The normal counterpart of the neoplastic B cells in Burkitt lymphoma (BL) is still unclear. Based on immunoglobulin gene rearrangement studies, some authors suggest an origin from germinal center cells and others from memory B cells. However, most of these studies rely on cell lines or on a small series of cases. To help clarify the cell of origin of BL, semi-nested polymerase chain reaction (PCR) was performed to amplify the VDJ rearrangements of the immunoglobulin heavy chain (VH) genes, and the resultant amplificates were sequenced for comparison with known germline VH segments. The results of this approach revealed that all cases (15 endemic BL [eBL], 10 sporadic BL [sBL], and 6 AIDS-related BL) harbor mutated VH genes, with different mutation ranges among the 3 types of BL. The eBL and AIDS-related forms showed considerably higher mutation rates than the sBL form (5.1%, 5.4%, and 1.5%, respectively). The mutations in eBL and AIDS-related BL also showed signs of antigen selection, whereas no signs of antigen selection were found in sBL. Finally, after subcloning the amplificates, sequence analysis revealed no signs of ongoing mutations in any of the cases analyzed. Given that one of the main differences between eBL and AIDS-related BL on the one hand and sBL on the other hand is the association with Epstein-Barr virus (EBV), we compared EBV-positive and EBV-negative BLs independently of their geographic origin and HIV status. The differences in the number of somatic mutations and antigen selection were even more evident when this approach was used. According to our molecular results, it appears that EBV-positive and EBV-negative BL may originate from 2 distinct subsets of B cells, pointing to a particular role for the germinal-center reaction in the pathogenesis of these tumors. The different types of C-MYC translocation reported in BL may also be related to the different stages of B-cell maturation.

Cytologic diagnosis of Burkitt lymphoma

BACKGROUND

The diagnosis and classification of lymphoma require correlation of morphologic, immunophenotypic, and molecular-cytogenetic studies. Fine-needle aspiration biopsy (FNAB) is a valuable diagnostic technique that allows material to be collected for these ancillary studies, and for morphologic evaluation.

METHODS

The authors report a series of seven cases clinically or morphologically suspicious for Burkitt lymphoma. Fluorescence in situ hybridization studies (FISH) for c-myc were performed on FNAB material and correlated with cytologic and immunophenotypic data.

RESULTS

Six of seven specimens were positive for c-myc rearrangement by FISH. However, only three of these cases represented Burkitt lymphoma, with one additional case of atypical Burkitt lymphoma. The other cases included diffuse large B-cell lymphoma, monomorphic posttransplant B-cell lymphoma, and an aggressive B-cell lymphoma, with the latter case negative for c-myc rearrangement by FISH. Of 2 non-Burkitt lymphoma specimens tested, 1 was positive for the immunoglobulin H/bcl-2 rearrangement, in addition to the c-myc rearrangement, suggesting transformation from a lower grade lymphoma.

CONCLUSIONS

These cases illustrated the value of FNAB in the diagnosis of Burkitt lymphoma, as well as the importance of obtaining material for, and integrating results of, ancillary studies for the final diagnosis.

Bone marrow endothelial cells in multiple myeloma secrete CXC-chemokines that mediate interactions with plasma cells

Bone marrow endothelial cells (EC) from patients with multiple myeloma (MM) were found to express and secrete higher amounts of the CXC-chemokines CXCL8/interleukin (IL)-8, CXCL11/interferon-inducible T-cell alpha chemoattractant (I-TAC), CXCL12/stromal cell-derived factor (SDF)-1alpha, and CCL2/monocyte chemotactic protein(MCP)-1 than EC from human umbilical vein (HUVEC), considered as a healthy counterpart. Paired plasma cells and several MM cell lines expressed cognate receptors of each chemokine to a variable extent. When cells were exposed to chemokines, CXCL8/IL-8 and CXCL12/SDF-1alpha stimulated their proliferation and all chemokines stimulated cell chemotaxis. It is suggested that angiogenesis also favours MM progression through the release of CXC-chemokines.

Paraffin section interphase fluorescence in situ hybridization in the diagnosis and classification of non-hodgkin lymphomas

Cytogenetic data can contribute valuable information that may assist in the diagnosis and classification of non-Hodgkin lymphomas and may in some cases also provide prognostic information. Interphase fluorescence in situ hybridization (FISH) studies offer the ability to assess for characteristic cytogenetic abnormalities even when material for standard metaphase cytogenetic analysis is not available. This review discusses the use of FISH in paraffin-embedded material with particular attention paid to the use of intact thin paraffin sections. The basic principles of FISH analysis are summarized, the advantages and disadvantages of analysis of thin paraffin sections rather than intact nuclei are discussed, and the more commonly encountered artifacts are considered. Each of the well-characterized cytogenetic abnormalities that are associated with particular types of non-Hodgkin lymphoma and can be detected with commercially available FISH probes is discussed individually. In particular, their incidence in various types of lymphoma is reviewed, the types of commercially available FISH probes to detect such abnormalities are discussed, and clinical situations where such analysis can be of diagnostic utility are described.

Maternal origin of inflammatory leukocytes in preterm fetal membranes, shown by fluorescence in situ hybridisation

The aim of this study was to determine the maternal or fetal origin of inflammatory leukocytes in fetal membranes from cases of chorioamnionitis. Fetal membranes were collected from male preterm infants and chorioamnionitis was diagnosed histologically. Fluorescence in situ hybridisation for X and Y chromosomes was used to determine the gender of infiltrating leukocytes in the chorion and amnion. Leukocytes, trophoblast and mesenchymal cells were identified using immunohistochemistry for CD45, cytokeratin-7 and vimentin, respectively. Leukocytes present in the chorion and amnion were labelled XX, indicating maternal origin, and these cells were immunoreactive for the leukocyte marker CD45 but not for vimentin or cytokeratin-7. All other cells in the chorion and amnion were labelled XY and of fetal origin. The results indicated that maternal leukocytes invade the amnion and chorion in chorioamnionitis and we suggest that this is part of the maternal inflammatory response to intrauterine infection.

Molecular diagnosis in lymphoma

The evolution of our ability to diagnose and classify lymphomas in an increasingly refined manner has paralleled the development of novel technologic approaches, with contemporary practice dependent upon the harnessing of a plethora of data that include microscopic, immunophenotypic, and genetic information. Although each of these components is currently indispensable, there is a purported progressive improvement in biologic objectivity as one maneuvers through these respective technologies. Accordingly, and in particular given the rapid pace at which key insights into lymphoma biology are emerging with microarray and other cutting-edge technologies, the role of molecular genetic testing is assuming even greater relevance. The ability to diagnose and classify lymphomas more accurately, precisely, and rationally by incorporating molecular data ought to lead to the development of more appropriate directed therapies.

Formalin-Fixed and Paraffin-Embedded Nodal Non-Hodgkin???s Lymphomas Demonstrate the Same Chromosome Changes as Those Found in Frozen Samples: A Comparative Study Using Interphase Fluorescence In Situ Hybridization

Cytogenetic studies in lymphomas classically require fresh or frozen tissue, whereas in many instances only paraffin-embedded biopsies are available. We applied an interphase FISH assay on nuclei extracted from thick paraffin sections to determine accuracy of molecular cytogenetics in such samples. Twenty-three lymphoma samples and 4 reactive lymph nodes were tested with various commercially available DNA probes, and hybridization patterns were compared with those obtained on frozen nuclei counterparts. Successful hybridization with all probes tested was observed for 23/27 (85%) paraffin-embedded tissues and for all (100%) frozen samples, and cut-off levels defining positivity were superimposable for both situations. Chromosome changes were detected in the same way, without any false-positive or false-negative cases. Hybridization signals observed on dewaxed samples were either those classically expected to define the relevant chromosome change or were atypical: all atypical changes could be demonstrated also into nuclei from the frozen counterpart. Moreover, all typical and atypical chromosome changes observed on frozen nuclei were also detected in paraffin-embedded tissues. Our study shows that our interphase FISH assay performed on paraffin-embedded samples is a valuable alternate to conventional methods to ascertain diagnosis of lymphomas as to include patients into therapeutic trials.

Interphase fluorescence in situ hybridization for detection of 8q24/MYC breakpoints on routine histologic sections: validation in Burkitt lymphomas from three geographic regions

A chromosomal translocation involving the MYC gene is characteristic of Burkitt lymphoma (BL) and represents a molecular disease marker with diagnostic and clinical implications. The detection of MYC breakpoints is hampered by technical problems, including the distribution of the breakpoints over a very large genomic region of approximately 1,000 kb. In this article, we report on the testing and validation of a segregation fluorescence in situ hybridization (FISH) assay for MYC breakpoints on a large series of BLs. A contig of overlapping genomic clones was generated, and two probe sets flanking the MYC gene were selected. Both probe sets were tested in an interphase FISH segregation assay on 8 B-cell lymphoma cell lines and 32 lymphoma samples with proved 8q24/MYC abnormalities and validated in 47 BLs from The Netherlands, Brazil, and Uganda. MYC translocation breakpoints were identified in 98% of the tumors of the test series and in 89% of the cases of the validation series. In 89% of all positive samples, the breakpoints were located between 190 kb 5' and 50 kb 3' of MYC. Nine cases had more distant breakpoints, and in one patient an insertion of MYC into the IGH region was detected. In two of the three BLs lacking CD10 expression, no breakpoint could be detected, suggesting that CD10 is a discriminative marker of BL. We did not find consistent differences between BL and atypical BL in incidence of an MYC breakpoint.

Simultaneous detection of the immunophenotypic markers and genetic aberrations on routinely processed paraffin sections of lymphoma samples by means of the FICTION technique

Disciplines such as morphology, immunophenotyping and genetics widely contributed over decades to the understanding of the cellular mechanisms of cancer. To obtain a greater insight into the complex processes of tumorigenesis, scientists have joined their efforts to combine many of the available techniques. Here, we report on the development of a FICTION (Fluorescence Immunophenotyping and Interphase Cytogenetics as a tool for the Investigation of Neoplasms) technique that allows a simultaneous detection of immunophenotypic markers and genetic aberrations on routinely processed lymphoma samples. As the antigen retrieval method seems to play an important role in the final results, we tested the pressure-cooking method at different times (2, 4 and 8 min) using three different buffers (EDTA, Tris-EDTA and citrate), resulting in improved sensitivity for the detection of both immunophenotypic markers and genetic aberrations. We also applied this method to different types of lymphoma using double immunofluorescence assays (including CD30, CD20, CD8 monoclonal antibodies) and several fluorescence in situ hybridization probes to demonstrate that the FICTION technique could be easily applied on paraffin sections in different combinations for the diagnosis and research of cancer.