The Value of Fluorescence In Situ Hybridization and Polymerase Chain Reaction in the Diagnosis of B-Cell Non-Hodgkin Lymphoma by Fine-Needle Aspiration

Inconclusive flow cytometric surface light chain results; can cytoplasmic light chains, Bcl-2 expression and PCR clonality analysis improve accuracy of cytological diagnoses in B-cell lymphomas?

BACKGROUND

Flow cytometric immunophenotyping (FCI), is widely used in cytology for distinguishing between B-cell lymphoma (BCL) and reactive lymphocytic proliferations (RLP), mainly by identifying monotypic B-cell populations. Since this cannot always be determined by ratios of surface immunoglobulin light chains (sIg LCs) we wanted to assess if cytoplasmic immunoglobulin (cIg) LCs, Bcl-2 and polymerase chain reaction (PCR) based clonality analysis can improve accuracy of cytological diagnoses of BCL.

METHODS

Our study included 98 fine needle aspiration biopsies from lymph nodes suspicious for BCL with inconclusive sIg LCs. In all cases PCR clonality analysis was performed in order to determine immunoglobulin heavy chain (IGH) gene and T-cell receptor (TRC) gene rearrangement. In selected cases expression of Bcl-2 and cIg LC were determined by FC.

RESULTS

Thirty patients had lymphoma and 68 had reactive lymphocytic proliferations. Three patterns of sIg LCs staining were found: negative, dual positive and difficult to interpret. Percentage of lymphomas was highest in the dual positive group (75 %). Morphology coupled with cIg LCs determination and/or Bcl-2 expression was able to give a correct diagnosis in 83 % of cases. Molecular tests would have been misleading in 15 % of cases because 7/30 BCL were polyclonal and 8/68 RLP were monoclonal.

CONCLUSIONS

Determination of cIg LCs, Bcl-2 expression and PCR clonality analysis of B cells improved accuracy of cytological diagnoses in BCL with inconclusive sIg LC. However, clonality determined by PCR was misleading in some cases.

Molecular diagnostic testing of cytology specimens: current applications and future considerations

Molecular mechanisms of pathogenesis continue to be discovered, accelerating significant expansion of the spectrum of clinically useful molecular diagnostic tests and their incorporation into patient care algorithms. Currently, molecular assays facilitate identification of infectious processes, detection of specific constitutional and somatically acquired pathogenic mutations, guidance of therapy selection, and monitoring of treatment response and disease progression. The correlation of genomic test results with clinical, morphologic, and immunophenotypic findings has defined the practice of "precision medicine" with wide-reaching implications for health care. As novel promising techniques such as microarrays and next-generation sequencing are adopted by health care providers, new practice standards are being developed for incorporation into practice. Cytology specimens are good sources of high-quality nucleic acids. Although sometimes limited in quantity, in many cases such specimens are well suited for molecular diagnostic testing, which is capable of maximizing the number of tests from small amounts of sample. The pathologist continues to serve as a central resource for diagnostic testing and consultation regarding appropriate use of molecular tests. Understanding current methodologies, clinical utility of currently available nucleic acid tests, validation requirements for test implementation, quality assurance metrics, and future technology trends is essential to the practice of contemporary molecular pathology.

Lymphadenopathy in a series of Egyptian pediatric patients and the role of pathology in the diagnostic workup

Assessment of lymphadenopathy in children represents a diagnostic challenge because of the extensive differential diagnoses, including reactive and malignant conditions. Knowledge of the etiologic pattern of lymphadenopathy in a given geographical region is essential for making a confident diagnosis or for suspecting a disease. Hence, the present study was carried out to identify different etiologies of lymphadenopathy in children in our region and to assess parameters commonly associated with malignancy, with an emphasis on the role of pathology. One hundred and twenty patients aged 1 month to 18 years were included in the study. They were sorted into neoplastic and nonneoplastic (infectious and noninfectious) groups. In 56 patients, biopsy (fine needle aspiration cytology [FNAC], core needle, or excision biopsy) was essential to reach the final diagnosis. Sensitivity of FNAC in the differentiation between neoplastic and nonneoplastic lymphadenopathy was 92.3%, and specificity was 90.0%, with a diagnostic accuracy of 91.3%. We concluded that malignancy should be suspected in the following conditions: presence of abdominal or multiple symptoms; symptom duration of 1-6 months; generalized lymphadenopathy; multiple groups of lymph node (LN) involved; LN size > 2 cm; amalgamated, hard, fixed, and nontender LNs; certain abnormal complete blood count findings; blast cells in blood film; and elevated lactate dehydrogenase level. In such cases, LN biopsy is highly recommended. A final diagnosis was achieved after integrating information from history and clinical findings with the laboratory, radiological, pathological, and microbiological findings. Accordingly, an algorithm for primary diagnostic evaluation of children with lymphadenopathy is suggested.

[Role of cytology in hematopathological diagnostics]

The role of cytology has so far been underrecognized in the diagnostic process of hematopathological questions. This article presents an algorithm which allows a stepwise work-up of cytology specimens obtained by minimally invasive ultrasound-guided fine needle aspiration in patients with unexplained lymph node swelling. Moreover, it is shown how the selective separation of cytology specimens allows the application of immunophenotypic analysis including flow cytometry and immunohistochemistry as well as molecular analyses, such as fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) strategies. With the integrative procedure presented, cytology offers an excellent cost-effective tool for the diagnostic approach of patients with suspected hematopathological malignancies allowing a high diagnostic accuracy, ideal for initial diagnosis or follow-up.

Immunoglobulin heavy-chain fluorescence in situ hybridization-chromogenic in situ hybridization DNA probe split signal in the clonality assessment of lymphoproliferative processes on cytological samples

BACKGROUND

The human immunoglobulin heavy-chain (IGH) locus at chromosome 14q32 is frequently involved in different translocations of non-Hodgkin lymphoma (NHL), and the detection of any breakage involving the IGH locus should identify a B-cell NHL. The split-signal IGH fluorescence in situ hybridization-chromogenic in situ hybridization (FISH-CISH) DNA probe is a mixture of 2 fluorochrome-labeled DNAs: a green one that binds the telomeric segment and a red one that binds the centromeric segment, both on the IGH breakpoint. In the current study, the authors tested the capability of the IGH FISH-CISH DNA probe to detect IGH translocations and diagnose B-cell lymphoproliferative processes on cytological samples.

METHODS

Fifty cytological specimens from cases of lymphoproliferative processes were tested using the split-signal IGH FISH-CISH DNA probe and the results were compared with light-chain assessment by flow cytometry (FC), IGH status was tested by polymerase chain reaction (PCR), and clinicohistological data.

RESULTS

The signal score produced comparable results on FISH and CISH analysis and detected 29 positive, 15 negative, and 6 inadequate cases; there were 29 true-positive cases (66%), 9 true-negative cases (20%), 6 false-negative cases (14%), and no false-positive cases (0%). Comparing the sensitivity of the IGH FISH-CISH DNA split probe with FC and PCR, the highest sensitivity was obtained by FC, followed by FISH-CISH and PCR.

CONCLUSIONS

The split-signal IGH FISH-CISH DNA probe is effective in detecting any translocation involving the IGH locus. This probe can be used on different samples from different B-cell lymphoproliferative processes, although it is not useful for classifying specific entities. Cancer (Cancer Cytopathol) 2012;. © 2012 American Cancer Society.

The role of fluorescence in situ hybridization and polymerase chain reaction in the diagnosis and classification of lymphoproliferative disorders on fine-needle aspiration

BACKGROUND

Fine-needle aspiration (FNA) has been used in the evaluation of lymphadenopathy for a long time and is highly reliable in the identification of metastatic malignancies. However, the role of FNA in the assessment of new lymphoproliferative disorders continues to be a subject of debate. The objective of the current study was to evaluate the role of molecular cytogenetic studies in FNA diagnoses of lymphoproliferative disorders.

METHODS

A retrospective, computer-based search for lymph node FNAs from 2006 to 2007 was performed. Cases with either fluorescence in situ hybridization (FISH) and/or polymerase chain reaction (PCR) studies were subjected to further analysis.

RESULTS

In total, 243 lymph node FNAs were performed during the period, including 104 that were positive/suspicious for metastatic malignancies, 16 that were positive/suspicious for lymphomas, 15 that demonstrated atypical lymphoid proliferation, 73 that were reactive, 14 that were deemed granulomas, and 21 that were determined to be nondiagnostic. Molecular analysis included combined FISH/PCR in 4 cases, FISH only in 7 cases, and PCR only in 4 cases. By using multiplex PCR, 6 cases with atypical/negative flow cytometry results were diagnosed as 4 B-cell lymphomas, 1 T-cell lymphoma, and 1 reactive lymph node; and 4 cases that had atypical T cells determined by flow cytometry were diagnosed as reactive. One CD10-negative follicular lymphoma and 2 cases with suspicious flow cytometry results were positive for t(14;18)(q32;q21) by FISH. Forty-five cases had follow-up histology with 3 false-negative findings and no false-positive results.

CONCLUSIONS

In this study, multiplex PCR studies for immunoglobulin heavy-chain or T-cell receptor gene rearrangements were useful for demonstrating clonality, and FISH studies were able to detect translocations or gene rearrangements that allowed for the subclassification of B-cell non-Hodgkin lymphomas.

Investigation of bone marrow involvement in malignant lymphoma using fluorescence in situ hybridization: possible utility in the detection of micrometastasis

We evaluated the usefulness of interphase fluorescence in situ hybridization (FISH) for the detection of bone marrow involvement of lymphoma, comparing the results with those of microscopic examination. Bone marrow aspirates obtained for staging work-up from 150 patients with non-Hodgkin lymphoma were used in this study. Interphase FISH study using four probes and conventional G-banding were performed on bone marrow aspirates. The four probes included locus specific identifier (LSI) immunoglobulin heavy chain (IGH) dual-color break-apart rearrangement probe, an LSI p16 SpectrumOrange/CEP 9 SpectrumGreen probe, an LSI BCL6 dual-color break-apart rearrangement probe. Among 150 cases, 29 cases (19.3%) showed infiltration of neoplastic lymphoid cells by microscopic examination. Chromosomal aberrations were detected by FISH in eight patients and by conventional cytogenetic study in three patients. FISH study showed 14q32 rearrangement in four patients (4/126, 3.2%), 9q21 rearrangement in no patients (0/144, 0%), 3q27 rearrangement in four patients (4/131. 3.1%), and a gain of 1q21q32 in two patients (2/115, 1.7%). Among eight patients with abnormal FISH patterns, six had normal karyotypes or no analyzable metaphase according to the conventional cytogenetic study. Seven patients with FISH abnormality showed bone marrow involvement of lymphoma by microscopic examination. One patient, who was defined as having no evidence of bone marrow involvement by microscopic examination, showed a 3q27 aberration in the FISH study. Although the number of patients with BM involvement that was detected by FISH was low, abnormal FISH patterns were detected in six patients who did not have abnormal karyotypes. Therefore, FISH analysis would be beneficial in cytogenetic diagnosis and follow-up study of minimal residual diseases, once the cytogenetic changes are detected at initial diagnosis.

Applications of molecular techniques to fine-needle aspiration biopsy

The effectiveness of fine-needle aspiration biopsy (FNAB) for rendering a specific diagnosis can be improved by applying several ancillary modalities. This review details several applications of molecular techniques using FNAB specimens with an emphasis on those used for patient care. A detailed search of the literature was conducted to collect all reports that used FNAB for different types of molecular tests. Several types of molecular tests, including in-situ hybridization, polymerase chain reaction, Southern blotting, and gene microarrays using FNAB specimens have been reported. These tests have been used with different organ systems and different objectives, including the detection of cancer cells, diagnosis, distinction of benign and malignant disease, prediction of response to chemotherapy, risk assessment, and selection of patients for targeted therapy. Except for a few tests such as assessment of HER2/neu for gene amplification in breast cancer, detection of clonality in hematopoietic neoplasms, and specific chromosomal translocations in the former and in the diagnosis of soft tissue sarcoma, most of the molecular tests using FNAB specimens are currently investigational. The reported literature indicates the excellent potential of using material procured from FNAB for almost any type of molecular test. Whereas few of these tests alone are used for patient care, some of them have the potential for clinical use in the near future.

Desmoplastic small round cell tumor: Using FISH as an ancillary technique to support cytologic diagnosis in an unusual case

Desmoplastic small round cell tumor is a rare and aggressive neoplasm that predominantly affects young males. In almost all cases, a reciprocal translocation is present resulting in the fusion of the Ewing sarcoma gene with the Wilms' tumor gene. Here we describe an unusual case occurring in a 59-year-old male, in which fluorescence in situ hybridization (FISH) was used in conjunction with immunohistochemical studies to confirm the diagnosis. To our knowledge, this is the first reported case of using FISH as an ancillary technique to confirm the cytologic diagnosis of this tumor.

Role of ancillary techniques in diagnosing and subclassifying non-Hodgkin's lymphomas on fine needle aspiration cytology

Non-Hodgkin's lymphomas (NHL) are tumours of the lymphoid cells. During the process of development of lymphoid cells, neoplasia may evolve at any point. Neoplastic cells usually carry the imprint of cell of origin at the stage of origin. Various types of NHL may have similar morphology with wide variation in origin, immunophenotype and other biological features. Different ancillary laboratory techniques may help to overcome the limitations of morphology in this aspect. The commonly used ancillary techniques in lymphomas are immunocytochemistry (IC), flow cytometry, Southern blot (SB) technique, polymerase chain reaction (PCR) and fluorescent in situ hybridization (FISH). In addition, laser scanning cytometry (LSC) and DNA microarray technologies are in the research phase. Various laboratory techniques are used for immunophenotyping, demonstration of monoclonality, identification of chromosomal translocation, assessment of cell kinetics and expression of mRNA in the tumour cells. Flow cytometry helps in rapid immunophenotying of NHL and it has an added advantage over IC in recognizing the co-expression of CD markers. Fine needle aspiration cytology (FNAC) combined with flow immunophenotyping may help us to diagnose and subclassify certain NHLs, such as follicular lymphoma and mantle cell lymphoma, which were previously recognized as pure morphological entities. Loss of morphology is one of the important limitations of flow cytometry. LSC can overcome this limitation by studying morphology along with the immunophenotyping pattern of individual cells. Chromosomal changes in NHL can be identified by SB, PCR and FISH. Molecular diagnosis of NHL helps in diagnosis, subclassification, prognostic assessment and even in planning of therapy. DNA microarray is a relatively newer and promising technology. It gives information about the expression of several thousands of genes in a tumour in a single experiment. In the near future, FNAC combined with ancillary techniques may play a major role in diagnosis, subclassification and management of lymphomas.

Fine-needle aspiration cytology combined with flow cytometry immunophenotyping is a rapid and accurate approach for the evaluation of suspicious superficial lymphoid lesions

The authors report a prospective study on 88 samples of superficial lesions (lymph nodes, skin nodules, and breast tumors), performed by fine-needle aspiration cytology (FNAC) in 74 patients, allowing (i) morphologic analysis combined with immunophenotyping by flow cytometry (FCM) and (ii) a cytogenetic study in 33 cases. Thirty-nine FNAC (44.3%) were performed at the time of diagnosis. The cytology results were correlated with histopathologic examination in 32 cases. Forty-nine FNAC (55.7%) were performed in the context of follow-up of a lymphoma and the results were correlated with those of histopathologic examination in 14 cases. In this study, the concordance between FNAC plus FCM and histopathologic examination was 90% for low-grade non-Hodgkin's malignant lymphomas (NHLs) and 83% for high-grade NHL. The limits of this morphologic and phenotypic approach are (i) partial tumor infiltrations, (ii) Hodgkin lymphoma, and (iii) T-cell NHL. In conclusion, it may be said that this combined approach is very useful for diagnosis and follow-up of patients but requires teams experienced in the sampling technique and the morphologic diagnosis of the various types of low-grade NHL in which supplementary ancillary studies may be performed when morphology and flow cytometry immunophenoyping are not conclusive.

The feasibility of gene expression profiling generated in fine-needle aspiration specimens from patients with follicular lymphoma and diffuse large B-cell lymphoma

Lymphoma of germinal center cell (GC) origin generally is an indolent malignancy that transforms progressively into a more aggressive disease. According to the World Health Organization classification, lymphomas of follicular center cell origin are classified as either large B-cell lymphoma (LBCL) or follicular lymphoma (FL). The authors tested the feasibility of performing gene expression profiling using amplified RNA from fine-needle aspirates (FNA) obtained from lymph nodes. Twenty-four samples from patients with a diagnosis of FL or LBCL were obtained after Institutional Review Board-approved informed consent was obtained. The diagnoses were confirmed by 2 pathologists and were classified into 2 groups (10 LBCL samples and 14 FL samples) by using conventional morphology and immunophenotyping. One hundred nanograms of total RNA were subjected to 2 cycles of standard, double-stranded complementary DNA synthesis and in vitro transcription for target amplification using a small-sample target-labeling protocol. The biotinylated cRNA from each sample was hybridized to gene chips. Gene expression profiling results were analyzed first by principal-component analysis (PCA) by using a list of 146 probe sets that represented 62 genes that are characteristic of an activated B-cell (ABC) signature or a GC signature. The analysis identified 5 LBCL samples with an ABC cell signature. Using a list of 207 probe sets that represented 113 genes involved in FL transformation, PCA analysis identified 2 overlapping clusters corresponding to FL and GC-diffuse LBCL. To improve this classification further, the authors generated a list of 72 genes that were expressed differentially between FL and GC-LBCL. Using this list of genes, PCA analysis demonstrated a clear separation between FL and GC-LBCL. However, five FL samples clustered as an intermediate group between FL and GC-DLBCL. These samples were characterized morphologically by a mixed cell pattern with relatively fewer large, noncleaved lymphocytes and more small, cleaved lymphocytes. The results support the feasibility of FNA-based transcription profiles in patients with FL or LBCL, which, in combination with morphology and immunophenotyping, can help in the subtyping of these entities.

Role of polymerase chain reaction and immunocytochemistry in the cytological assessment of lymphoid proliferations

BACKGROUND

Fine-needle aspiration cytology (FNAC) is used as a screening test to evaluate lymphadenopathy. The combined use of genetic analysis and flow cytometry for immunophenotyping has increased the accuracy of diagnosis and correct categorisation of lymphomas on cytological preparations.

AIM

To show the utility of immunocytochemistry and polymerase chain reaction (PCR) in the evaluation of cytological preparations of lymph nodes.

METHODS

Fine needle aspirates were obtained from 33 patients (initial presentation, n = 27; recurrence, n = 6). Routine examination was undertaken using immunocytochemistry and DNA PCR to detect clonality and specific translocations. The cytodiagnosis and subclassification of lymphoma was correlated with histological diagnosis in the available follow-up biopsies.

RESULTS

14 patients had a cytological diagnosis of non-Hodgkin's lymphoma (NHL), 4 had suspected NHL, 2 had atypical lymphoid proliferation and 13 had reactive hyperplasia. A World Health Organization (WHO) subtype was suggested in 8 patients. Incorporating the results of immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements enabled diagnosis of lymphoma in 17 patients, including 5 of the 6 patients suspected to have NHL or an atypical lymphoid proliferation. Identification of the translocations t (14;18) and t (2;5) helped WHO categorisation in 3 of the patients. The cytological findings were confirmed in 12 out of the 13 patients for whom histological follow-up was available. Seven of the 18 lymphoma patients were managed without a subsequent biopsy. We made one false-positive diagnosis of B-cell NHL on cytology.

CONCLUSION

The use of immunocytochemistry and PCR is valuable in the definitive diagnosis and subtyping of malignant lymphomas on cytological preparations. The use of these techniques may avoid lymph node biopsies in some cases and allow definitive treatment based on aspirate findings alone.

Grading follicular lymphoma on fine-needle aspiration specimens-A practical approach

Fine-needle aspiration biopsy (FNA) is a useful tool for evaluating and staging follicular lymphoma (FL) without subjecting patients to multiple excisional biopsies. The relative lack of architecture in FNA is a limitation in grading FL. Recognizing the various cellular components in aspirates of FL, correlating with flow cytometry, using other ancillary tests, and preparing cell blocks can help overcome difficulties in the grading process. Understanding the clinical relevance of distinguishing the various grades of FL is important in determining whether an aspiration biopsy is adequate or whether additional sampling by surgical biopsy is indicated.