SEARCH

SEARCH BY CITATION

Keywords:

  • fine needle aspiration;
  • fluoresce in situ hybridization;
  • B-cell non-Hodgkin lymphoma;
  • lymph node;
  • cytopathology

Abstract

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONFLICT OF INTEREST DISCLOSURES
  7. REFERENCES

BACKGROUND:

Fluorescence in situ hybridization (FISH) results from fine needle aspirates (FNA) of B-cell non-Hodgkin lymphomas (NHLs) were reviewed to 1) investigate the value added by using specific gene rearrangement probes to lymphoma diagnosis, prognosis, and subtyping; and 2) evaluate the prevalence of cytogenetic alterations other than specific translocations.

METHODS:

FISH results from assays performed on cytospin preparations from NHL FNAs over a 6-year period (2003-2009) were selected. Immunophenotyping, clinical data, and cytomorphologic data were reviewed according to the current World Health Organization (WHO) classification system. Hybridized probes, the purpose for the assay (subtyping or prognosis), and the cytogenetic abnormalities observed were retrieved from cytology reports. Data was categorized according to specific rearrangements and other chromosomal abnormalities.

RESULTS:

Successful results were obtained in 284 (95.3%) of 298 cases from 282 patients. Abnormalities were found in 216 (76%) cases and 68 (24%) did not show alteration. Among cases submitted for subtyping, 198 showed FISH-positive results, and specific gene rearrangements were found in 122 (61.6%) cases as follows: follicular 82, mantle cell 21, marginal zone 3, “dual hit” 13, and Burkitt lymphoma 3. In 21 cases, abnormalities were useful for prognosis. Nonspecific alterations alone or in combination with translocations were found in 98 cases.

CONCLUSIONS:

FISH performed on cytospin preparations was useful for confirmation of specific subclasses of NHL and may also provide valuable prognostic information. Cytogenetic abnormalities other than specific translocations were frequently found and could provide supportive evidence for a definitive diagnosis of lymphoma in FNA. Cancer (Cancer Cytopathol) 2010. © 2010 American Cancer Society.

Cytogenetic analysis has led to the identification of distinctive chromosomal abnormalities, especially translocations and amplification of gene regions that are often uniquely associated with morphologically and clinically distinct subsets of lymphomas.

Fluorescence in situ hybridization (FISH) is a robust and reliable technique for the identification of primary karyotypic abnormalities that are often closely associated with an individual lymphoma subtype, and, thus, FISH can be diagnostically useful in identifying lymphoma-associated translocations. Furthermore, appropriate FISH probe sets are ideally suited to cover the variable breakpoints of these translocations. Recent studies have demonstrated that FISH assays detect twice as many t(14;18)-positive follicular lymphomas as polymerase chain reaction (PCR) assays.1

Chromosomal abnormalities other than specific translocations also occur in hematologic malignancies,2, 3 and studies have demonstrated that the genes involved in some rearrangements may be secondarily translocated to another chromosome.4, 5 The incidence and prognostic significance of those secondary aberrations are being explored by routine and conventional cytogenetics.6 Recent array-comparative genomic hybridization (aCGH) studies have identified nonrandom copy-number aberrations, and findings indicate that each lymphoma has a unique genomic profile.7

Cytogenetic analyses have provided fundamental insights into the genetic basis of pathogenesis of lymphomas, and correspondingly, those studies have played a crucial role in clinical management.3 FISH assays have been designed and are commercially available for identification of the most frequent specific chromosomal abnormalities pertinent to diagnosis as well as for detection of prognostic markers that can determine optimum therapeutic approaches, allowing suitable patients to be targeted for aggressive and potentially curative therapy.

Improved diagnostic efficiency has been achieved by the combination of flow cytometry, immunophenotyping, and cytomorphology in the workflow of lymph node fine-needle aspiration (FNA). More homogeneous data and reproducible results have been generated by different laboratories using both techniques.8 However, few studies have investigated the value added by molecular techniques. A recent review highlighted some of the major impediments to widespread clinical use of FNA samples for targeted cancer-therapy decisions. This review emphasized that preanalytical specimen handling and processing methods, the cellular composition of FNA samples, and tumor heterogeneity may profoundly impact downstream molecular test results.9 It is, thus, relevant to review FISH results obtained from cytological preparations to evaluate their consistency and reliability.

FISH analysis has been successfully applied to FNA samples for the detection of specific chromosomal translocations in follicular lymphoma (FL),10, 11, 12 mantle cell lymphoma (MCL),13, 14 and anaplastic large cell lymphoma (ALCL).15 Those studies used 1 or 2 probes for the diagnosis of 1 specific subtype. The technique has also been performed in samples from small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) using a panel of probes for prognosis.16 However only 1 large series of 106 FNA cases reviewed FISH results in unstained smears and compared them to flow cytometry to determine the ability of FISH analysis to diagnose and/or subclassify B-cell non-Hodgkin lymphoma (NHL).17

This study aimed to review FISH results obtained from cytospin preparations from FNA samples of NHL using a multiparameter diagnostic approach to 1) investigate diagnostic, prognostic and subtyping information provided by specific probes, and 2) evaluate prevalence and describe cytogenetic alterations other than specific translocations found by the FISH assays.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONFLICT OF INTEREST DISCLOSURES
  7. REFERENCES

Case Selection

An electronic search of the Cytogenetics database was performed to select fine needle aspiration (FNA) cases with a final diagnosis of NHL submitted for fluorescence in situ hybridization (FISH) during the period from October 2003 to September 2009. All cases were reviewed and subtyped according to the recent World Health Organization (WHO) classification and included follicular lymphoma (FL), small lymphocytic lymphoma (SLL), marginal zone lymphoma (MZL), mantle cell lymphoma (MCL), small B-cell lymphoma(SBCL) not otherwise specified (NOS), large B-cell lymphoma (LBCL), Burkitt lymphoma (BL), and B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma (U-DLBL/BL).

For the original diagnosis, a multiparametric approach to classification was adopted that emphasized cytomorphological immunophenotypic studies and, in some cases, relied on cytogenetic and/or genotypic studies. Papanicolaou-stained and/or Romanowsky-stained smears were used for cytomorphological assessment.

Demographic, immunophenotypic, and molecular data were retrieved from cytology reports. These data included site of the FNA, patient age, and patient sex. From the molecular report, the following information was collated: number and type of probes, the purpose for the assay (subtyping or prognosis), the presence of specific translocations, and other cytogenetic abnormalities.

Research ethics approval for this study was sought and obtained from the human tissue committee at the University Health Network.

Immunoprofiling

Immunophenotyping was performed on fresh needles rinses by using Laser Scanning Cytometry (LSC) after the Clatch protocol.18, 19 This technique has been validated in our laboratory and shown to provide equivalent results to flow cytometry.20 Imaging cytometers LSC or iCys (CompuCyte, Cambridge, Mass) and WinCyte software or iCys 3.4 (CompuCyte) with events contoured on the basis of forward light scatter/laser light absorbance were used for analysis. A full panel consisted of the following monoclonal antibodies: CD19, CD20, CD3, CD5, CD10, kappa, lambda, CD22, CD23, FMC7, CD4, CD8, CD56, CD7, CD2, CD25, CD14, CD11c, and CD16. The antibody clones along with concentrations, fluorochromes, and suppliers have been previously described.20

Cytospin preparations were made from the remaining cells suspended in saline used for immunophenotyping. The slides were then fixed in 95% ethanol while wet and sent for FISH and immunohistochemistry.

Immunocytochemistry

MIB-1 immunocytochemistry for proliferation index assessment was performed on cytospin preparations by using a monoclonal antibody against MIB-1 (monoclonal mouse-antihuman; clone MIB-1; Dako, Carpinteria, Calif) and either the i-view DAB avidin-biotin detection kit or Ventana ultra view DAB chromogen kit (Ventana Medical Systems, Tucson, Ariz). Epitope retrieval and antibody incubation time followed the same protocol used for formalin fixed paraffin embedded (FFPE) tissues. The percentage of MIB-1 positive nuclei was considered to be the MIB-1 proliferation index (PI) and was retrieved from the cytologic report.

FISH Assays

FISH assays were performed on cytospin preparations by using 1 or more probes of the following probes: IGH/BCL2 to detect t(14;18) (q32;q21.3), IGH/ CCND1 to detect t(11;14)(q13;q32), IGH/MYC:CEP8 to detect t(8;14)(q24;q32) (Dual Color Dual Fusion Probes), IGH, MALT1, MYC (Break Apart Probes), as well as enumeration/copy number probes CEP 3 (D3Z1), CEP 12 (D12Z3), 13q14 (D13S319), 13q34 (D13S25/LAMP1), ATM/D11Z1 and 17p13 (TP53), CEP17 (D17Z1) (Abbott/Vysis, Des Plaines, Ill). Probes sets were selected on the basis of initial clinical, cytomorphologic, and immunophenotyping data.

The manufacturer's protocol was followed (Vysis; Abbott Laboratories, Abbott Park, Ill) with minor changes as follows: slides were placed in a dry oven at 60°C for 1 hour and incubated in 2× SSC for 30 minutes at 37°C in a water bath. Slides were then dehydrated in a sequential ascending ethanol series (70%, 95%, and 100%) for 2 minutes each and air-dried. Probe was added to the slide, cover slipped, sealed with rubber cement, and codenaturated by using a microprocessor-controlled system (Hybrite; Vysis) at a melting temperature of 75°C for 1 minute. Hybridization was carried out at 37°C overnight. Posthybridization washes consisted of 0.4× SSC/0.3% NP-40 at 72°C for 2 minutes and 0.1% NP-40 of 2× SSC at room temperature for 1 minute. Slides were air dried in a dark chamber followed by chromatin counterstaining with DAPI/mounting medium (Vectashield medium; Vector, Burlingame, Calif) and cover slipped.

Prior to July 2008, Zeiss AxioPlan and the Zeiss AxioSkop microscopes were used for analysis. Beginning in July 2008, analyses were performed by using an epifluorescence microscope (Zeiss Axio Imager, Gottingen, Germany) equipped with a triple bandpass filter set (DAPI/Green/Orange), dual bandpass filter set (Green/Orange), and single bandpass filters (DAPI, Green & Orange). Since July 2008, image capture was performed by using a digital ProgRes MF video camera (Jenoptik, Jena, Germany) and the fluorescent image acquisition software ISIS (MetaSystems, Altlussheim, Germany). Prior to July 2008, Applied Imaging's MacProbe 4.4 (Santa Clara, Calif) was used.

Criteria for scoring were established before performing FISH assays. Nuclei with signals from each fluorochrome and complete DAPI nuclear staining were randomly selected for scoring. Signals must be clear and distinct with no cross hybridization and no diffuse signals. Clinical evaluation studies for each probe set were completed to determine normal cutoffs and abnormal reference ranges for each signal pattern observed. Two hundred nonoverlapping interphase nuclei were scored by 2 technologists.

For the purpose of this study, cases were classified as positive, negative, and failed assay. Cases were also subdivided according to the purpose of the assay, ie, subtyping or prognosis. Positive cases included all cases with specific translocations, numerical chromosomal alteration detected with the use of probes for chromosomal enumeration (prognosis), and other chromosomal abnormalities (OCA) detected with probes hybridized for that specimen. Therefore, positive cases hybridized with probes detecting translocations were subgrouped as translocation alone, translocation with other chromosomal abnormalities (OCA), or with OCA in the absence of translocation.

RESULTS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONFLICT OF INTEREST DISCLOSURES
  7. REFERENCES

A total of 298 FNA specimens with a final diagnosis of lymphoma, originating from 282 patients, were found to have FISH studies performed on cytospin preparations. There were 143 men and 139 women. Their ages ranged from 20 to 88 years (median, 62 years). There were 230 FNA from lymph nodes and 68 from an extranodal site.

Cytomorphologic and Immunophenotypic Evaluation (CIE)

The diagnoses based on the initial cytomorphologic evaluation in combination with the immunophenotypic profile and MIB-1 proliferative index (immunohistochemistry) were grouped according to the current WHO classification. There were 113 cases of FL grades 1-2, 6 cases of FL grade 3, as well as 22 of MZL, 23 of SLL/CLL, 21 of MCL, 21 of SBCL, 72 of LBCL, 13 of U-DLBL/BL, 1 of BL, 2 B-cell NHL- NOS (Non-Hodgkin lymphoma, not otherwise specified) and 4 suspicious for lymphoma.

Chromosomal Abnormalities Detected by FISH

FISH assays were successful in 284 (95.3%) cases. In 14 cases, no results were obtained; corresponding to an assay failure rate of 4.7%. A total of 264 cases were submitted for subtyping, and in 22, a prognostic panel was ordered. In 2 cases, the probes used had both purposes. One or more chromosomal abnormalities were detected in 216 (76%) cases, and 68 cases did not show any abnormality. (Table 1) Specific chromosomal translocations were not detected in 111 cases submitted for subtyping, which consisted of 45 cases showing other chromosomal abnormalities and 66 cases with no abnormalities identified. Of the 22 cases submitted for prognosis, only 2 cases were negative for the panel of probes used.

Table 1. FISH Results According to Final Cytologic Diagnosis
Cytologic DiagnosisTotal (%)FISH PositiveFISH NegativeFailed Assay
  1. SBCL NOS indicates small B-cell lymphoma not otherwise specified; U-DLBL/BL-DT, “double hit” or “dual translocation” lymphoma; U-DLBL/BL, unclassifiable with intermediate features between diffuse large B-cell lymphoma and Burkitt lymphoma; NHL, non-Hodgkin lymphoma.

Follicular lymphoma126 (42.3)98217
Mantle cell lymphoma23 (7.7)2120
Marginal zone lymphoma21 (7.0)9120
SBCL NOS11 (3.7)650
Small lymphocytic lymphoma23 (7.7)1652
Large B-cell lymphoma65 (21.8)43184
U-DLBL/BL-DT13 (4.4)1300
U-DLBL/BL8 (2.7)611
Burkitt lymphoma3 (1.0)300
NHL, B-cell4 (1.3)130
Suspicious1 (0.3)010
Total2982166814

Among the cases with positive FISH results, 100 showed translocations alone, 53 displayed the specific translocations plus other aberrations, and 45 showed other aberrations and no translocation. (Table 2) Evaluation of FISH results for each lymphoma subtype according to final cytological diagnosis, which combined cytomorphologic and immunophenotypic data with MIB-1 proliferative index and FISH, showed that specific subtyping was obtained in 122 lymphomas, which included FL, MCL, MZL, U-DLBL/BL-DT, and BL. In FL among 126 cases, 82 (65.1%) were positive for IGH/BCL2, and 16 showed other chromosomal abnormalities (OCA), whereas in MCL, positive results for IGH/CCND1 probe were obtained in 21 (91.3%) of 23 cases assayed. Among those, 4 cases showed concurrent OCA (Fig. 1). For MZL, only 3 (13.6%) cases showed positive results among 21 cases hybridized for MALT1, and 6 cases showed OCA. Among aggressive and highly aggressive lymphomas, 16 cases were identified as having MYC rearrangements. In 13 cases, there were concurrent translocations (IGH/BCL2 and MYC), and they were definitely categorized as U-DLBL/BL-DT (B-cell lymphoma, unclassifiable, with features between diffuse large B-cell lymphoma and Burkitt lymphoma with dual translocation), and in 3 cases of Burkitt lymphoma, MYC probe was positive.

thumbnail image

Figure 1. A case of mantle cell lymphoma. Direct smears (A) MGG and (B) Papanicolaou staining showing a monotonous population of slightly enlarged lymphoid cells with irregular nuclear contours interrupted by occasional histiocytes (C) Immunophenotyping by laser scanning cytometry - Gating on small CD45 positive lymphoid cells shows a pure population of B cells with moderate expression for CD19, and bright for CD20 and sIg with kappa light chain restriction. The clonally restricted lymphocytes express CD5, but are negative for CD10 (D) FISH results using IGH/CCND1 dual-color dual-fusion probe - red signals indicate CCND1gene, green signals IGH and yellow signals a fusion of the two probes due to t(11;14). Extra copies of all signals are identified.

Download figure to PowerPoint

Table 2. FISH Positive Results According to Cytologic Diagnosis and the Presence of Specific Translocations and Other Chromosomal Abnormalities
Cytologic DiagnosisFISH with Positive Results
 TranslocationTranslocation & OCAOCATotal No. (%)
  1. OCA indicates other chromosomal abnormalities; SBCL NOS, small B-cell lymphoma not otherwise specified; U-DLBL/BL-DT, “double hit” or “dual translocation” lymphoma; U-DLBL/BL, unclassifiable with intermediate features between diffuse large B-cell lymphoma and Burkitt lymphoma; NHL, non-Hodgkin lymphoma.

Follicular lymphoma55271698 (49.5)
Mantle cell lymphoma174021 (10.6)
Marginal zone lymphoma3069 (4.5)
SBCL NOS0066 (3.0)
Large B-cell lymphoma13131541 (20.7)
U-DLBL/BL-DT94013 (6.6)
U-DLBL/BL2316 (3.0)
Burkitt lymphoma1203 (1.5)
NHL0011 (0.5)
Total1005345198

In 29 cases, FISH results added important information for the final diagnosis and changed the initial diagnosis based on cytomorphologic and immunophototypic evaluation (CIE). These consisted of 10 cases of FL that had a diagnosis of SBCL (8 cases) and 2 cases deemed suspicious for lymphoma, 13 cases of U-DLBL/BL-DT with previous CIE of LBCL-NOS (6 cases), U-DLBL/BL (4 cases), and FL (3 cases); 2 cases of MCL classified by CIE as SBCL; 2 BL classified as U-DLBL/BL; 1 NHL classified as suspicious for lymphoma, and 1 U-DLBL/BL classified as LBCL.

The probes most commonly used were dual color dual fusion probes. (Table 3) In 117 cases, the IGH/BCL2 translocation was detected. This translocation was observed in 82 (75.2%) of 109 follicular lymphomas with positive results and in 20 (33.9%) cases of 59 cases of LBCL. In 23 cases of MCL, 21 showed the specific translocation t(11,14)(q13;q32). MYC rearrangement, when using either the break-apart probe or the dual color dual fusion probe, was detected in 27 cases. IGH/MYC probe was positive in 2 and MYC break apart in 25 cases. In 7 cases of LBCL-NOS, MYC was positive.

Table 3. FISH Results According to Probes to Specific Rearrangements and Cytologic Diagnosis
Cytologic DiagnosisTypes of Probes
 Dual Color Dual Fusion ProbesBreak Apart Probes
 IGH/BCL2IGH/CCND1IGH/MYCIGHMALT1MYC
  1. FL indicates follicular lymphoma; MCL, mantle cell lymphoma; MZL, marginal zone lymphoma; SBCL NOS, small B-cell lymphoma not otherwise specified; LBCL, large B-cell lymphoma; U-DLBL/BL-DT, “double hit” or “dual translocation” lymphoma; U-DLBL/BL, unclassifiable with intermediate features between diffuse large B-cell lymphoma and Burkitt lymphoma; BL, Burkitt lymphoma.

FL8200100
MCL0210000
MZL000030
SBCL NOS000000
LBCL2001306
U-DLBCL/BL-DT13001013
U-DLBCL/BL200003
BL001003
Total1172125325

In 22 cases, a FISH panel was requested for prognostic purposes. Those cases included SLL/CLL (18 cases) in which the following probes were positive: ATM/D11Z1 (7 cases), CEP12 (6 cases), D13S319, D13S25/LAMP1 (9 cases), TP53 (3 cases). In 2 cases with a previous history of SLL submitted for the CLL prognostic panel the final diagnosis was LBCL (transformation). These cases were positive for D13S319, D13S25/LAMP1 (1 case) and TP53 (2 cases). One case of MCL was negative for copy number alteration of CEP12 and 1 SBCL showed trisomy 12. These 2 cases were also tested for IGH/CCND1 probe.

The category of other chromosomal abnormalities (OCA) consisted of patterns that differed from the classic alterations including extra fusion signals and/or extra loci signals, losses of signals, and complex patterns. No specific pattern was identified. The most commonly detected numerical alterations were extra copies of IGH (16 cases), MYC (15 cases), and BCL2 (14 cases). Among extra fusion signals, extra fusion of IGH/BCL2 (10 cases) was the most common abnormality. Combined alterations (extra copy number and extra fusion) were identified in 9 cases and complex pattern in 3. (Table 4)

Table 4. Summary of Other Chromosomal Abnormalities
Other Chromosomal AbnormalitiesNo. of Cases
Extra copy 
 IGH16
 MYC15
 BCL214
 MALT14
 MYC & BCL26
 BCL2 & MALT13
 MYC & IGH1
 MYC, IGH & BCL22
 IGH, BCL2 & MALT11
Extra fusion 
 IGH/BCL210
 IGH/CCND11
Extra copy+Extra fusion 
 MYC & IGH/BCL25
 BCL2 & IGH/BCL21
 IGH & IGH/BCL21
 MALT1 & IGH/BCL21
 IGH, BCL2 & IGH/BCL21
One copy 
 IGH2
Complex pattern3
Others11
Total98

DISCUSSION

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONFLICT OF INTEREST DISCLOSURES
  7. REFERENCES

We have confirmed that by incorporating the results of cytogenetic data with cytomorphology and immunophenotyping, a definitive classification with subtyping can be reached in a high proportion of cases of B-cell NHL FNA. The use of cytospin preparations can optimize aliquoting of FNA for multiple tests, including FISH assays, necessary for a multiparameter approach. Moreover, we also demonstrated that crucial information for prognosis in some lymphoma subtypes can be derived from FNA and that other chromosomal abnormalities are frequently identified in NHLs by the use of probes targeting specific translocations.

The current study is the largest series to show the usefulness of using specific probes for the subtyping of NHL in cytological specimens. In the only previous large retrospective study of FISH in NHL FNA, 59 cases were submitted for further classification.17 Of these, 23 (39%) cases were subclassified by using FISH results alone. We were able to specifically subtype 121 (65%) cases. In contrast to that study in which a large number of cases were analyzed by using a limited panel (kappa/lambda/CD20/CD10 or kappa/lambda/CD19/CD5) with 4-color flow cytometry (FC), in the majority of our cases, a full panel of antibodies was used for Laser Scanning Cytometry. LSC permits a larger panel of antibodies because it requires smaller sample volumes relative to FC, unless 6 + color analysis is used, and many laboratories have not yet implemented these protocols.

Successful FISH analysis for the diagnosis of lymphoma in FNA using different types of cytologic preparations including unstained smears,11, 17 Papanicolaou-stained, or Diff-Quik-stained archival slides12, 14 has been previously described. The use of cytospin preparations for FISH tests has also been explored for some lymphoma subtypes and in small number of cases10, 16, 21, 22; however, no previous studies have evaluated the consistency of FISH tests on cytospin preparations within a large series of different NHL subtypes.

Our study showed an overall failure rate of 5%, lower than that in a previous study that used destained archival alcohol-fixed smears, in which 15% of the cases failed to produce an adequate signal for counting.12 In a series that used unstained smears, only 2 (1.9%) of the 106 cases submitted for FISH studies failed to hybridize.17 The difference was attributed to issues related to destaining and alcohol fixation.17 In addition, we may speculate that the length of time lymphoid cells had remained in saline before cytospin preparation might have affected hybridization efficiency because single-cell suspension usually enables individual cell evaluation, clear signal detection, and straightforward cell scoring.

In our series, the expected rate of positivity was found for all specific lymphoma subtypes. Not all cases within a particular lymphoma category necessarily harbor the expected translocation. For FL, we found 65.1% positivity for IGH/BCL2. A study describes that dual-color, dual-fusion FISH with the use of IGH/BCL2 probe can detect t(14;18) in 64% to 100% of follicular lymphomas.23 Crucial information for patient management not obtained with other ancillary techniques and cytomorphology were provided by FISH analysis. Some types of lymphoma are characterized by multiple chromosomal changes that can often be of prognostic value. In 34 cases (SLL/CLL and “dual translocation”), the results were primarily of prognostic importance. Moreover, 9 cases diagnosed by cytomorphology and immunophenotyping as FL (3 cases) and LBCL (6 cases) were classified as “dual translocation” (dual hit) lymphomas after FISH studies. The “dual hit” lymphomas are characterized by the presence of t(14,18), usually detected in FL and the t(8;14)(q24;q32) translocation commonly found in Burkitt lymphoma. In the current WHO classification, they are included in the U-DLBL/BL category. Recent studies have provided important data about the clinical behavior of this aggressive type and the clinicopathologic characteristics have just been described.24, 25

FISH, unlike PCR, can also potentially detect, although not definitively characterize, certain complex cytogenetic abnormalities indicative of complex karyotypes.26 In 98 of our cases, other abnormalities different from the classic translocations were identified. It has been pointed out that these unusual patterns should not be ignored but should be considered abnormal.27 A previous study that used cytological imprint from surgical specimens reported atypical patterns with some translocation probes.28 Although such abnormalities are generally too nonspecific to assist in lymphoma classification, the demonstration of aneusomy within a lymphoid proliferation does provide evidence that the proliferation represents a lymphoma rather than a reactive process.2 In 72 of our cases, extra copies of some genes were identified. In most of our cases, immunophenotyping had already confirmed clonality. However, when immunophenotyping is ambiguous, then cytogenetic abnormalities may add important information for confirmation of a lymphoma diagnosis. A recent review emphasized that each lymphoma entity has characteristic nonrandom copy number aberration patterns with gains for particular chromosomes or chromosome regions. The finding that each disease entity has a unique genomic profile indicates that these genomic alterations play some role in the pathogenesis of each lymphoma subtype. Explorations of target genes for these genomic regions are 1 of the most important research areas for an understanding of the molecular mechanisms of lymphoma development.7 In this retrospective study, probes were selected according to initial clinical, cytomorphologic, and immunophenotyping data; therefore, the category of OCAs might have been underestimated. Prospective studies that use probe sets based upon recent CGH studies may detect a larger number of cases with recurrent numerical abnormalities.

Prognostic analyses of chromosomal alterations in MCL in a series that used conventional cytogenetics and FISH showed a range of results. The degree of karyotypic complexity29 and the presence of 3 or more structural aberrations30 were found to be associated with poor survival. Recently, a multivariate analysis demonstrated that gains of 3q and losses of 17p in MCL added prognostic significance to the morphology.6 Interestingly, high numbers of numerical and structural alterations were found in that study, but no secondary recurrent rearrangement was identified. The full clinical significance of additional chromosomal abnormalities other than translocations has yet to be established.

In conclusion, with the use of commercially available FISH probes, important diagnostic and prognostic data can be obtained with assays performed on cytospin preparations of lymph node FNA, thus enabling the identification of specific B-cell NHLs. Other chromosomal abnormalities can also be identified in the absence of specific translocations, and these alterations can be used to support the diagnosis of a lymphoproliferative disorder. This may be especially beneficial when immunophenotyping data are not available or clonality cannot be determined.

REFERENCES

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONFLICT OF INTEREST DISCLOSURES
  7. REFERENCES
  • 1
    Chang CM, Schroeder JC, Huang WY, et al. Non-Hodgkin lymphoma (NHL) subtypes defined by common translocations: utility of fluorescence in situ hybridization (FISH) in a case-control study. Leuk Res. 2010; 34: 190-195.
  • 2
    Cook JR. Paraffin section interphase fluorescence in situ hybridization in the diagnosis and classification of non-Hodgkin lymphomas. Diagn Mol Pathol. 2004; 13: 197-206.
  • 3
    Sreekantaiah C. FISH panels for hematologic malignancies. Cytogenet Genome Res. 2007; 118: 284-296.
  • 4
    Gazzo S, de Colella JM, Callet-Bauchu E. Sequential fluorescence in situ hybridisation analysis for cryptic t(11;14)(q13;q32) in mantle cell lymphoma. Br J Haematol. 2006; 134: 452.
  • 5
    Salaverria I, Zettl A, Bea S, et al. Specific secondary genetic alterations in mantle cell lymphoma provide prognostic information independent of the gene expression-based proliferation signature. J Clin Oncol. 2007; 25: 1216-1222.
  • 6
    Espinet B, Salaverria I, Bea S, et al. Incidence and prognostic impact of secondary cytogenetic aberrations in a series of 145 patients with mantle cell lymphoma. Genes Chromosomes Cancer. 2010; 49: 439-451.
  • 7
    Seto M, Honma K, Nakagawa M. Diversity of genome profiles in malignant lymphoma. Cancer Sci. 2010; 101: 573-578.
  • 8
    Zeppa P, Vigliar E, Cozzolino I, et al. Fine needle aspiration cytology and flow cytometry immunophenotyping of non-Hodgkin lymphoma: can we do better? [published online ahead of print February 1, 2010] Cytopathology. PMID: 20132132.
  • 9
    Clark DP. Seize the opportunity: underutilization of fine-needle aspiration biopsy to inform targeted cancer therapy decisions. Cancer Cytopathol. 2009; 117: 289-297.
  • 10
    Gong Y, Caraway N, Gu J, et al. Evaluation of interphase fluorescence in situ hybridization for the t(14;18) (q32;q21) translocation in the diagnosis of follicular lymphoma on fine-needle aspirates: a comparison with flow cytometry immunophenotyping. Cancer. 2003; 99: 385-393.
  • 11
    Safley AM, Buckley PJ, Creager AJ, et al. The value of fluorescence in situ hybridization and polymerase chain reaction in the diagnosis of B-cell non-Hodgkin lymphoma by fine-needle aspiration. Arch Pathol Lab Med. 2004; 128: 1395-1403.
  • 12
    Richmond J, Bryant R, Trotman W, Beatty B, Lunde J. FISH detection of t(14;18) in follicular lymphoma on Papanicolaou-stained archival cytology slides. Cancer. 2006; 108: 198-204.
  • 13
    Caraway NP, Gu J, Lin P, Romaguera JE, Glassman A, Katz R. The utility of interphase fluorescence in situ hybridization for the detection of the translocation t(11;14)(q13;q32) in the diagnosis of mantle cell lymphoma on fine-needle aspiration specimens. Cancer. 2005; 105: 110-118.
  • 14
    Bentz JS, Rowe LR, Anderson SR, Gupta PK, McGrath CM. Rapid detection of the t(11;14) translocation in mantle cell lymphoma by interphase fluorescence in situ hybridization on archival cytopathologic material. Cancer. 2004; 102: 124-131.
  • 15
    Shin HJ, Thorson P, Gu J, Katz RL. Detection of a subset of CD30+ anaplastic large cell lymphoma by interphase fluorescence in situ hybridization. Diagn Cytopathol. 2003; 29: 61-66.
  • 16
    Caraway NP, Thomas E, Khanna A, et al. Chromosomal abnormalities detected by multicolor fluorescence in situ hybridization in fine-needle aspirates from patients with small lymphocytic lymphoma are useful for predicting survival. Cancer. 2008; 114: 315-322.
  • 17
    Monaco SE, Teot LA, Felgar RE, Surti U, Cai G. Fluorescence in situ hybridization studies on direct smears: an approach to enhance the fine-needle aspiration biopsy diagnosis of B-cell non-Hodgkin lymphomas. Cancer Cytopathol. 2009; 117: 338-348.
  • 18
    Clatch RJ, Walloch JL, Zutter MM, Kamentsky LA. Immunophenotypic analysis of hematologic malignancy by laser scanning cytometry. Am J Clin Pathol. 1996; 105: 744-755.
  • 19
    Clatch RJ, Walloch JL. Multiparameter immunophenotypic analysis of fine needle aspiration biopsies and other hematologic specimens by laser scanning cytometry. Acta Cytol. 1997; 41: 109-122.
  • 20
    Al-Za'abi AM, Geddie WB, Boerner SL. Equivalence of laser scanning cytometric and flow cytometric immunophenotyping of lymphoid lesions in cytologic samples. Am J Clin Pathol. 2008; 129: 780-785.
  • 21
    Jiang F, Lin F, Price R, et al. Rapid detection of IgH/BCL2 rearrangement in follicular lymphoma by interphase fluorescence in situ hybridization with bacterial artificial chromosome probes. J Mol Diagn. 2002; 4: 144-149.
  • 22
    Zhang S, Abreo F, Lowery-Nordberg M, Veillon DM, Cotelingam JD. The role of fluorescence in situ hybridization and polymerase chain reaction in the diagnosis and classification of lymphoproliferative disorders on fine-needle aspiration. Cancer Cytopathol. 2010; 118: 105-112.
  • 23
    Gu K, Chan WC, Hawley RC. Practical detection of t(14;18)(IgH/BCL2) in follicular lymphoma. Arch Pathol Lab Med. 2008; 132: 1355-1361.
  • 24
    Snuderl M, Kolman OK, Chen YB, et al. B-cell lymphomas with concurrent IGH-BCL2 and MYC rearrangements are aggressive neoplasms with clinical and pathologic features distinct from Burkitt lymphoma and diffuse large B-cell lymphoma. Am J Surg Pathol. 2010; 34: 327-340.
  • 25
    Tomita N, Tokunaka M, Nakamura N, et al. Clinicopathological features of lymphoma/leukemia patients carrying both BCL2 and MYC translocations. Haematologica. 2009; 94: 935-943.
  • 26
    Einerson RR, Kurtin PJ, Dayharsh GA, Kimlinger TK, Remstein ED. FISH is superior to PCR in detecting t(14;18) (q32;q21)-IgH/bcl-2 in follicular lymphoma using paraffin-embedded tissue samples. Am J Clin Pathol. 2005; 124: 421-429.
  • 27
    Ventura RA, Martin-Subero JI, Jones M, et al. FISH analysis for the detection of lymphoma-associated chromosomal abnormalities in routine paraffin-embedded tissue. J Mol Diagn. 2006; 8: 141-151.
  • 28
    Buno I, Nava P, Alvarez-Doval A, Alvarez-Rodriguez F, Diez-Martin JL, Menarguez J. Lymphoma associated chromosomal abnormalities can easily be detected by FISH on tissue imprints. An underused diagnostic alternative. J Clin Pathol. 2005; 58: 629-633.
  • 29
    Cuneo A, Bigoni R, Rigolin GM, et al. Cytogenetic profile of lymphoma of follicle mantle lineage: correlation with clinicobiologic features. Blood. 1999; 93: 1372-1380.
  • 30
    Katzenberger T, Kienle D, Stilgenbauer S, et al. Delineation of distinct tumour profiles in mantle cell lymphoma by detailed cytogenetic, interphase genetic and morphological analysis. Br J Haematol. 2008; 142: 538-550.