Use of novel t(11;14) and t(14;18) dual-fusion fluorescence in situ hybridization probes in the differential diagnosis of lymphomas of small lymphocytes

A prospective trial of adjuvant therapy for high-risk uveal melanoma: assessing 5-year survival outcomes

Background/aims

Survival after diagnosis of metastasis from uveal melanoma is poor. Identifying individuals at high risk for metastasis and developing adjuvant therapy to prevent clinically apparent metastasis could improve survival. We conducted an adjuvant trial of sequential, low-dose dacarbazine (DTIC) and interferon-alpha-2b (IFN-α−2b) in patients with cytogenetic high-risk uveal melanoma.

Methods

Patients diagnosed with iris, ciliary body or choroidal melanoma with high-risk tumour cytogenetics (monosomy 3) were offered adjuvant treatment with low-dose DTIC and IFN-α−2b following primary therapy. Eligible but not enrolled patients were observed for comparison. DTIC was administered at 850 mg/m2 intravenously on days 1 and 28. IFN-α−2b was administered at 3 million units three times a week subcutaneously for 24 weeks beginning at week 9. Hepatic imaging was performed prior to adjuvant therapy and then at least every 6 months. Survival data were collected for 5 years after enrolment.

Results

33 patients (22%) were enrolled (treatment group), 29 (19%) were eligible but did not enrol (observation group) and 88 (59%) were not eligible. The 5-year metastasis-free survival (MFS) was 64%±9% for treated and 33%±10% for observed patients (p=0.05). The 5-year overall survival (OS) rate was 66%±9% for treated and 37%±10% for observed patients (p=0.02).

Conclusions

When adjusted for differences in age, tumour size and initial treatment, survival between treated and observed patients was no longer significant (p=0.56 MFS and p=0.92 OS). Differences in baseline tumour characteristics between treated and observed patients can influence interpretation of results.

Trial registration number

NCT01100528.

Fine-needle aspiration biopsy of uveal melanoma: outcomes and complications

PURPOSE

To report outcomes and complications of fine-needle aspiration biopsy (FNAB) of uveal melanoma performed for diagnostic and prognostic purposes.

METHODS

Prospective interventional case series of 150 consecutive patients with a clinical diagnosis of uveal melanoma. The FNAB approach (transcorneal (TCO), transscleral (TSC) and transvitreal (TVT) was primarily determined by the location of the tumour. The FNAB was performed using a 25-gauge needle using a previously published technique. Prognostication was done using fluorescent in situ hybridisation detection of monosomy of chromosome 3.

RESULTS

FNAB was obtained via TCO (8), TSC (71) and TVT (64) approach and impression smear in seven cases. Diagnostic yield was 92%. False-negative results were observed in 8%. Diagnostic yield was significantly correlated to biopsy approach (TCO 100%, TSC 96%, TSV 86%; p=0.029) and tumour size (basal diameter >5.0 mm; height >2.5 mm). Persistent haemorrhage (subretinal haemorrhage or vitreous) requiring surgical intervention (1%) and rhegmatogenous retinal detachment (1%) were rare. Endophthalmitis, hypotony, tumour recurrence, episcleral seeding were not observed over the average follow-up of 37 months. Prognostication could be performed in 85% of cases. Overall, only 47% of eligible patients enrolled into the adjuvant therapy trial.

CONCLUSIONS

FNAB for uveal melanoma with 25-gauge needle is a safe procedure that can yield diagnostic and prognostic information in vast majority of cases (92% and 85%, respectively). Even so, only about half of the eligible cases eventually enrolled into the adjuvant therapy trial. Possibility of negative FNAB yield should be considered when counselling patients with small tumours. Alternative means of diagnostic biopsy and methods of prognostication need to be assessed for small tumours.

Elevated blood β-2 microglobulin is associated with tumor monosomy-3 in patients with primary uveal melanoma

Prognostic blood biomarkers for patients with uveal melanoma have not been identified. Tumor monosomy-3 is strongly associated with the development of metastatic disease. Tumor expression of human leukocyte antigen class I molecules and insulin-like growth factor (IGF)-1 receptor has also been associated with the development of metastatic disease. The relationship of blood levels of the human leukocyte antigen-class-I-associated β-2 microglobulin (β2M), IGF-1, and its binding protein, IGFBP-3, with tumor monosomy-3 was evaluated. Blood was drawn from patients with a clinical diagnosis of primary uveal melanoma without metastatic disease before fine-needle aspiration biopsy at the time of brachytherapy or enucleation. Tumor chromosome 3 status was determined by fluorescence in-situ hybridization. β2M, IGF-1, and IGFBP-3 levels were determined using enzyme-linked immunosorbent assays. A total of 76 patients were studied; 47 (62%) underwent brachytherapy and 29 (38%) underwent enucleation. Thirty-three (43%) of the tumors manifested monosomy-3. Most tumors were large, located in the choroid, mixed cell type, and nuclear grade 2. Most tumors did not manifest extraocular extension. Blood levels of IGF-1 and IGFBP-3 were not associated with tumor monosomy-3. In contrast, increases in blood β2M (P≤0.02) were associated with tumor monosomy-3. The independent association of increased blood level of β2M and tumor monosomy-3 status was confirmed in multivariable analysis. In conclusion, measurement of blood levels of β2M in patients with primary uveal melanoma may have prognostic value and may help guide surveillance and adjuvant therapy recommendations.

Chromosome 3 status in uveal melanoma: a comparison of fluorescence in situ hybridization and single-nucleotide polymorphism array

PURPOSE

To compare fluorescence in situ hybridization (FISH) using a centromeric probe for chromosome 3 (CEP3) and 3p26 locus-specific probe with single-nucleotide polymorphism array (SNP-A) analysis in the detection of high-risk uveal melanoma.

METHODS

Fifty cases of uveal melanoma (28 males, 22 females) treated by enucleation between 2004 and 2010 were analyzed. Fresh tissue was used for FISH and SNP-A analysis. FISH was performed using a CEP3 and a 3p26 locus-specific probe. Tumor size, location, and clinical outcome were recorded during the 7-year study period (median follow-up: 35.5 months; mean: 38.5 months). The sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

RESULTS

Monosomy 3 was detected by FISH-CEP3 in 27 tumors (54%), FISH-3p26 deletion was found in 30 (60%), and SNP-A analysis identified 31 (62%) of the tumors with monosomy 3. Due to technical failures, FISH and SNP-A were noninterpretable in one case (2%) and two cases (4%), respectively. In both cases of SNP-A failure, tumors were positive for FISH 3p26 deletion and in a single case of FISH failure, monosomy 3 was found using SNP-A. No statistically significant differences were observed in any of the sensitivity or specificity measures.

CONCLUSIONS

For prediction of survival at 36 months, FISH CEP3, FISH 3p26, and SNP-A were comparable. A combination of prognostication techniques should be used in an unlikely event of technical failure (2%-4%).

Demonstration of array-based analysis for highly multiplexed PCR assays application to detection of IGH@-BCL2 translocations in FFPE follicular lymphoma specimens

We demonstrate an approach that allowed rapid development of a robust assay for the detection of chromosomal translocations. The method includes highly multiplexed PCR with analysis of the PCR products performed by array detection. As proof of principle, we applied this approach to the detection of IGH@-BCL2 translocations in DNA prepared from FFPE specimens. This translocation and specimen type were chosen because of the known difficulties associated with PCR-based detection of this lesion and the additional loss of sensitivity associated with FFPE samples. The multiplex PCR with array detection method detected the IGH@-BCL2 translocation in 26 of 36 FFPE follicular lymphoma specimens, whereas the BIOMED-2 assay detected 13 of 36 specimens. This increased sensitivity was the result of both the increased density of BCL2 primers and identification of PCR products by low-density array. The method was specific and allowed mapping of the BCL2 break point in all cases. The method detected the IGH@-BCL2 lesion when the tumor DNA was diluted more than 1:20 in normal DNA but not when it was diluted more than 1:100. This sensitivity allows detection of diagnostically relevant levels of IGH@-BCL2 but will not detect the rare cells with IGH@-BCL2 translocations in healthy individuals.

Indolent mantle cell leukemia: a clinicopathological variant characterized by isolated lymphocytosis, interstitial bone marrow involvement, kappa light chain restriction, and good prognosis

BACKGROUND

Cases of mantle cell lymphoma with indolent behavior have been reported, but are poorly identified by current clinical risk models. Early studies found peripheral blood involvement to be an adverse prognostic factor; however, cases of a seemingly indolent variant of mantle cell lymphoma, characterized by peripheral blood involvement and minimal nodal disease, have been incompletely described, particularly with regard to bone marrow findings. We report a series of leukemic phase mantle cell lymphomas with a non-progressive or slowly progressive course.

DESIGN AND METHODS

Cases presenting with mantle cell lymphoma limited to the peripheral blood/bone marrow from 2000-2010 were identified. Diagnoses were established by morphology, flow cytometric analysis and requisite evidence of IGH-CCND1@ by fluorescence in-situ hybridization or t(11;14)(q13;q32) by cytogenetics. Patients with lymphadenopathy, splenomegaly and gastrointestinal symptomatology were excluded.

RESULTS

Patients (n=8, median age 60.5 years) were asymptomatic with mild lymphocytosis (8.7×10(9)/L; range, 4.5-14.2×10(9)/L) and cytology typical of mantle cell lymphoma. Flow cytometric analysis showed that all expressed CD5, CD19, CD20, variable CD23, and a striking kappa immunoglobulin light chain restriction (7/8 cases). Bone marrow biopsy at diagnosis showed interstitial single or small lymphoid aggregates with similar patterns of CD20 and cyclin D1 immunostaining which were not readily discernable by hematoxylin and eosin stain. SOX11 was negative (4/5) or only weakly expressed (1/5). The median follow-up was 27 months (range, 5-109 months) and all patients, but one, are alive with no clinical evidence of disease. The prevalence of indolent mantle cell lymphoma presenting only with lymphocytosis, among all mantle cell lymphomas diagnosed during the same period, was 3%.

CONCLUSIONS

Leukemic mantle cell lymphoma limited to blood and bone marrow is an indolent variant characterized by mild-moderate lymphocytosis, interstitial low-level bone marrow involvement, simple karyotype, kappa light chain expression, cyclin D1 expression with lack of SOX11, and slow or absent clinical progression. Some cases may represent a mantle cell lymphoma counterpart to chronic lymphocytic leukemia - phenotype monoclonal B-cell lymphocytosis. Recognition of this variant could inform treatment decisions and possibly avoid unnecessary treatment.

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue arising in the lateral ventricle

Extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) lymphomas are a well-described type of low-grade B-cell non-Hodgkin lymphoma. They typically arise adjacent to mucosal surfaces in the gastrointestinal tract, lung and conjunctiva, and, less frequently, in the skin, salivary gland and thyroid gland. Unusual locations, such as the genitourinary tract, thymus and meninges, have also been reported. We recently encountered a case of an intracranial MALT lymphoma in a 53-year-old man who presented with persistent headaches and a seizure. The lesion developed as a mass within the lateral ventricle, appeared to be arising from the choroid plexus, and was not associated with meninges. Histologically, there was a vaguely nodular, dense lymphoid infiltrate with occasional benign follicles colonized by marginal zone lymphoma, suggesting derivation from a focus of prior inflammation. Translocations involving the MALT1 gene were not identified but karyotypic evaluation highlighted a complex cytogenetic profile with many chromosomal abnormalities. This rare case provides insight into the pathophysiology of MALT lymphomas.

Practical detection of t(14;18)(IgH/BCL2) in follicular lymphoma

The t(14;18)(q32;q21) translocation is the genetic hallmark of follicular lymphoma. Detection of this translocation can facilitate the diagnosis of follicular lymphoma and can be used to monitor response to therapy and level of residual disease. We herein review and compare practical techniques for detecting t(14;18)(q32;q21), including conventional cytogenetics, fluorescence in situ hybridization, Southern blot analysis, and polymerase chain reaction-based assay. Emphasis is placed on fluorescence in situ hybridization and polymerase chain reaction-based assay, given the applicability of these techniques to fixed, paraffin-embedded tissue.

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.

Tumor Cell Nuclei Extraction From Paraffin-Embedded Lymphoid Tissue for Fluorescence In Situ Hybridization

In this study the authors evaluated a technique for isolating intact tumor nuclei from paraffin-embedded lymphoma samples before performing FISH testing to detect the lymphoma-specific trans-location t(11;14) that defines mantle cell lymphoma. Well-characterized surgical pathology cases of mantle cell lymphoma were identified from pathology archives. Thin sections were cut from the paraffin-embedded tissue blocks. One section was stained using hematoxylin and eosin and an area composed exclusively of malignant cells was identified and marked on the slide. The corresponding area of the tissue block corresponding to this region underwent needle core biopsy, and the tissue was processed to isolate tumor cell nuclei and deposited onto a glass slide. The paired sample preparations underwent routine FISH testing for detection of the t(11;14)(q13;q32) chromosomal trans-location. DNA probe hybridization quality was compared between the tissue and isolated nuclei. Individual tumor cell nuclei were successfully extracted from each of the tissue blocks. The t(11;14) trans-location was detected by FISH in all of the samples diagnosed as mantle cell lymphoma. The hybridization signals found in the nuclei of extracted tumor cells were bright, planar, and easily identified. Detection of signal was superior to that on whole tissue samples, where signals often overlapped or were truncated. This technique produces intact nuclei for analysis, preserves the tissue block for additional studies, and allows sampling of a specific area of the tissue block. This approach may be particularly useful when the amount of diagnostic tissue is limited.

Expression profile and molecular genetic regulation of cyclin D1 expression in epithelioid sarcoma

Epithelioid sarcoma is a distinctive, aggressive soft tissue tumor typically presenting as a subcutaneous or deep dermal mass in the distal extremities of young adults. Molecular genetic data of well-characterized cases of epithelioid sarcoma are sparse. A recent cytogenetic study of epithelioid sarcoma by conventional metaphase comparative genomic hybridization reported recurrent gains at chromosome 11q13, a region containing many genes, including the cyclin D1 gene. Cyclin D1 is a positive cell cycle regulator that is overexpressed in a variety of neoplasms, including mantle cell lymphoma and breast carcinoma. The objective of this study was to examine cyclin D1 expression in epithelioid sarcoma. Of 24 cases evaluated, 23 (96%) displayed cyclin D1 nuclear expression using immunohistochemical evaluation. Eight cases, which expressed cyclin D1 by immunohistochemistry, were evaluated by fluorescence in situ hybridization (FISH) and RNA in situ hybridization (RISH) for amplification of the cyclin D1 gene and messenger RNA (mRNA) expression, respectively. Seven of eight cases showed a typical eusomic state. One case showed pseudoamplification due to aneusomy/polysomy. There was no evidence of cyclin D1 gene amplification or messenger RNA overexpression detected by FISH or RNA in situ hybridization analyses, respectively. Our data clearly demonstrate that cyclin D1 protein is upregulated in epithelioid sarcoma, suggesting a role for this cell cycle regulator in the pathogenesis of epithelioid sarcoma. The high level of cyclin D1 protein expression in epithelioid sarcoma appears to be regulated by translational and/or post-translational mechanisms.

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

BACKGROUND

Mantle cell lymphoma can be difficult to differentiate cytologically from other small cell non-Hodgkin lymphomas. Nevertheless, the distinction is important, because mantle cell lymphoma is more aggressive than other small cell non-Hodgkin lymphomas. The purpose of this study was to determine whether fluorescence in situ hybridization (FISH) is helpful in diagnosing mantle cell lymphoma on fine-needle aspiration (FNA) specimens by detecting the t(11;14)(q13;q32) translocation that is characteristic of this tumor.

METHODS

Fifty-five lymph node FNA specimens from 53 patients were analyzed using FISH. A 2-color FISH assay that employed probes at the 14q32 (immunoglobulin H) and 11q13 (dual-colored, directly labeled cyclin D1) loci was used. The number of single-fusion and double-fusion signals in 200 cells was counted. If > or = 14% single-fusion signals or > or = 1.5% double-fusion signals or both were present, then the sample was considered FISH positive. The findings were correlated with the cytologic, histologic, and immunophenotypic findings in each specimen.

RESULTS

Of the 55 cytology specimens, 17 were mantle cell lymphomas, and 38 were nonmantle cell lymphomas, including 16 small lymphocytic lymphomas (9 of 16 in an accelerated phase), 5 large cell lymphomas, 5 follicular lymphomas, 7 transformed large cell lymphomas (Richter syndrome), 3 atypical lymphoid proliferations, and 2 low-grade B-cell lymphomas. All 17 mantle cell lymphomas were positive by FISH. In addition, there were six small lymphocytic lymphomas (two in accelerated phase), one transformed large cell lymphoma, and one large cell lymphoma of follicular origin positive by FISH. The mean number of single-fusion and double-fusion signals, respectively, was 36 and 33 in mantle cell lymphoma specimens and 19 and 3 in positive nonmantle cell lymphoma specimens.

CONCLUSIONS

The detection of the t(11;14)(q13;q32) translocation by FISH analysis was helpful in diagnosing mantle cell lymphoma on FNA specimens. Double-fusion signals were more specific for mantle cell lymphoma than single-fusion signals. In rare instances, other non-Hodgkin lymphomas also showed increased numbers of single-fusion signals that were not necessarily indicative of the t(11;14)(q13;q32) translocation. Therefore, in an initial diagnosis of mantle cell lymphoma, significant numbers of double-fusion FISH signals should be identified and interpreted in conjunction with the cytologic and immunologic studies.

The role of molecular studies in lymphoma diagnosis: a review

Lymphoma classification is based on a multiparametric approach to diagnosis, in which clinical features, morphology, immunophenotype, karyotype and molecular characteristics are important to varying degrees. While in most cases, a diagnosis can be confidently established on the basis of morphology and immunophenotype alone, a small proportion of diagnostically difficult cases will rely on molecular studies to enable a definitive diagnosis. This review discusses the various molecular techniques available including Southern blotting (SB), polymerase chain reaction (PCR), fluorescence in situ hybridisation (FISH)--including multicolour-FISH/spectral karyotyping and comparative genomic hybridisation--and also gene expression profiling using cDNA microarray technology. Emphasis is given to the analysis of antigen receptor gene rearrangements and chromosomal translocations as they relate to lymphoma diagnosis and also in the setting of minimal residual disease (MRD) detection and monitoring. Laboratories performing these tests need to have expertise in these areas of testing, and there is a need for greater standardisation of molecular tests. It is important to know the sensitivity and specificity of each test as well as its limitations and the pitfalls in the interpretation of results. Above all, results of molecular testing should never be considered in isolation, and must always be interpreted in the context of clinical and other laboratory data.

Aberrant Bcl6 Protein Expression in Mantle Cell Lymphoma

Mantle cell lymphoma is routinely considered as a Bcl6-negative B-cell lymphoma carrying the translocation t(11;14). Here we describe a series of five Bcl6-positive mantle cell lymphoma cases, including three classic and two blastoid variants. The proliferative index of these cases, measured with the Ki-67 antibody, was slightly higher than in Bcl6-negative mantle cell lymphoma cases (32.2 vs. 23.7%) Bcl6 expression was associated with translocations involving 3q27 in four of the five cases and an extra copy of the BCL6 gene in the fifth. A mutational study of the major mutational cluster in the BCL6 gene revealed no increased mutation rate, except in one case. One of the three cases displayed a high mutational index in the IgVH gene, suggesting exposure to a germinal center microenvironment. Chromosomal alterations involving 3q27 seem to be responsible for this increased Bcl6 expression, which needs to be considered when Bcl6 is used in lymphoma diagnosis.

Evaluation of peripheral blood involvement of mantle cell lymphoma by fluorescence in situ hybridization in comparison with immunophenotypic and morphologic findings

Mantle cell lymphoma is non-Hodgkin's B-cell lymphoma characterized by the t(11;14)(q13;q32) translocation. Peripheral blood involvement of mantle cell lymphoma is usually associated with a poor prognosis and therefore, its identification is clinically important. In this study, we performed cyclin D1/IgH-probe fusion fluorescence in situ hybridization analysis on 223 peripheral blood samples: 185 from 125 mantle cell lymphoma patients, and 38 normal controls. The cutoff values for the test were established using normal controls. Flow cytometry on peripheral blood and corresponding bone marrow samples was used to evaluate this test. In all, 26% of the 185 peripheral blood samples and 27% of the 161 corresponding bone marrow samples were flow cytometry positive for mantle cell lymphoma. The mean numbers of single and- double-fusion signals and the mean number of CD5/CD19-positive cells, absolute blood lymphocyte count, and white blood cell count were significantly higher in peripheral blood and corresponding bone marrow samples with mantle cell lymphoma-positive flow cytometry. Double-fusion signals were more specific than single-fusion ones. Fluorescence in situ hybridization was far more likely to be positive for mantle cell lymphoma when the peripheral blood and the corresponding bone marrow samples had positive flow cytometry results or morphology (P<0.01). Our study indicates that cyclin D1/IgH-fusion fluorescence in situ hybridization analysis could be used to determine the presence and character of circulating mantle cell lymphoma cells in peripheral blood, thus enhancing our ability to evaluate leukemic mantle cell lymphoma and minimum residual disease.

Rapid detection of the t(11;14) translocation in mantle cell lymphoma by interphase fluorescence in situ hybridization on archival cytopathologic material

BACKGROUND

The cytomorphologic diagnosis of mantle cell lymphoma (MCL) can be difficult and requires ancillary studies for accurate subclassification. More than 95% of MCLs are known to carry the t(11;14) chromosomal translocation. However, traditional cytogenetic studies on cytologic material can be both difficult technically and time consuming. Interphase fluorescence in situ hybridization (FISH) can be a powerful tool for detecting chromosomal changes in individual tumor cells. The authors evaluated the utility of interphase FISH for the rapid detection of t(11;14) in archival cytologic material.

METHODS

The cytopathology data bases at two institutions were searched for patients with well characterized MCL (biopsy, immunophenotyping). Ten patients with MCL (8 fine-needle aspiration samples and 2 body cavity fluid samples) were identified. The area of interest on the cytology slides was marked and hybridized with two-color, locus-specific identifier DNA probes. A dual-fusion probe signal was used to detect the juxtaposition of the immunoglobulin heavy-chain (IgH) (14q32) locus with cyclin D1 (CCND1) gene sequences (11q13). Samples with tumor cell nuclei that showed at least one yellow fusion signal in addition one green signal (IgH) and one orange signal (CCND1) were interpreted as positive. Positive and negative controls were used.

RESULTS

The t(11;14) translocation was detected by FISH in 10 of 10 patients (100%) with MCL.

CONCLUSIONS

The cytomorphology of small-to-intermediate cell lymphomas, including MCL, follicular lymphoma, and marginal zone/mucosa-associated lymphoid tissue lymphoma, can show overlapping cytomorphologic features with one another as well as with reactive lymphoid proliferations. In selected samples in which specific classification is not possible or when confirmation is required on a small sample size, molecular analysis and cytogenetics may be helpful in arriving at an unambiguous cytodiagnosis and subclassification. Distinction of MCL from other lymphomas is important, because the clinical course is aggressive, and response to conventional chemotherapy is poor. This study showed that the detection of t(11;14) by FISH can be performed rapidly and easily on archival cytologic material for the molecular diagnosis of MCL.

Composite Hodgkin Lymphoma and Mantle Cell Lymphoma

Association of Hodgkin lymphoma and non-Hodgkin lymphoma is rare and, specifically, the combination of Hodgkin lymphoma and mantle cell lymphoma has not been previously described. Here we describe composite mantle cell lymphoma and Hodgkin lymphoma affecting the spleen in one case and the eyelid and cervical lymph nodes in a second. In both, nodules of classical Hodgkin lymphoma were intermixed with diffuse or nodular areas of typical mantle cell lymphoma. Immunohistochemical and molecular analyses confirmed cyclin D1 overexpression secondary to the translocation t(11;14) in the small mantle cell lymphoma component; with CD30, CD15, and EBV expression in the Hodgkin and Reed-Sternberg cells. Finally, clonal analysis of rearranged immunoglobulin genes performed on microdissected Hodgkin and Reed-Sternberg and mantle cell lymphoma cells provided definite evidence of separate clonal origins of the two tumors in the patients. These EBV-positive, clonally unrelated tumors seem to represent true composite neoplasms, in contrast to cases showing merely clonal progression.

Update in the pathologic features of mature B-cell and T/NK-cell leukemias

Modern diagnosis of mature B- and T-cell leukemias requires integration of morphologic, immunophenotypic, and molecular genetic features. This integrative approach has allowed more precise definitions of specific disease entities. This in turn provides better information for clinicians to select proper therapy and determine prognosis. The characteristic pathologic features of these disorders are reviewed.

The detection of t(14;18) in archival lymph nodes: development of a fluorescence in situ hybridization (FISH)-based method and evaluation by comparison with polymerase chain reaction

Fluorescence in situ hybridization (FISH) has been used to demonstrate the t(14;18) in up to 100% of follicular lymphoma (FL) cases, however, there is little reproducible data using fixed tissue. The aim was therefore to develop a robust FISH method for the demonstration of translocations in archival tissue. The technique was evaluated by comparison with multiplex polymerase chain reaction (PCR), capable of detecting the majority of known breakpoints. Twenty-eight paired frozen and fixed cases of FL and 20 reactive controls were analyzed. The t(14;18) was detected in 23 of 28 cases using PCR on frozen material and 8 of 20 in paraffin. Using FISH, 24 of 26 frozen and 26 of 28 paraffin cases had a demonstrable translocation. All 20 reactive nodes were negative for the t(14;18) by PCR. Using FISH, one of the reactive cases had occasional cells with a translocation FISH pattern, demonstrable in frozen and paraffin samples. This is consistent with the presence of the t(14;18), which is well described in normal individuals. Both PCR and FISH are highly effective for t(14;18) analysis in unfixed tissue. When only paraffin blocks are available, FISH is the method of choice, and a result was achieved in 100% of cases. The method is applicable to the retrospective analysis of a range of translocations.

Mantle cell lymphoma: improved diagnostics using a combined approach of immunohistochemistry and identification of t(11;14)(q13;q32) by polymerase chain reaction and fluorescence in situ hybridization

INTRODUCTION

Mantle cell lymphoma (MCL) is a clinicopathological entity characterized by an aggressive clinical course, morphological features, and overexpression of cyclin D1 due to juxtaposition of the bcl-1 locus (and CCND1 gene coding for the cyclin D1) to the IgH gene. This phenomenon is caused by t(11;14)(q13;q32). The morphological diagnosis of MCL may pose difficulties. Ancillary methods are available to support the diagnosis.

PATIENTS AND METHODS

We studied a group of 32 patients with MCL; 24 men and 8 women. The median age at the diagnosis was 64 years. We characterized the investigated group by histology, and to analyze the immunohistochemical (IHC) profile we used a panel of antibodies including anti-cyclin D1. Polymerase chain reaction (PCR) was used to detect the rearrangement of bcl-1/IgH in 26 cases (in 11 patients, the DNA was isolated from frozen tissues or from nucleated cells of bone-marrow aspirate or peripheral blood, in 15 patients we utilized paraffin-embedded material). Dual color fluorescence in situ hybridization (FISH) on interphase nuclei detecting the t(11;14)(q13;q32) was applied in all 32 cases.

RESULTS

Cyclin D1 IHC was positive in 29 of 30 cases tested (97%). In six, the result was weak and difficult to rely on to support the diagnosis. PCR revealed the fusion gene in 14 of the 26 cases (54%). The best yield was obtained from fresh and frozen samples (8 of 11 positive). Using FISH, we identified the translocation in all 32 patients, the findings being easily interpretable in 29 patients. In three cases, the intensity of red and green signals was weaker and difficult to read though the co-hybridized signals were identified. The classical pattern of the translocation was observed in 26 patients, while in 3 we found variant patterns suggesting a loss of the V segment of the IgH gene (2x) and a shift in the breakpoint region at chromosome 11 (1x).

CONCLUSION

The diagnosis of MCL should be supported by a complex laboratory approach. Interphase FISH seems a useful complementary method to morphology and IHC. It is applicable to various tissues and cells prepared as tissue imprints or histological sections.

Rapid detection of IgH/BCL2 rearrangement in follicular lymphoma by interphase fluorescence in situ hybridization with bacterial artificial chromosome probes

Follicular lymphomas (FLs) can be difficult to diagnose on aspirated specimens since the architectural pattern is not present. FLs characteristically have rearrangements in the IgH and BCL2 genes resulting from the reciprocal t(14;18) (q32; q21) translocation. Because of the dispersed distribution of breakpoints, fluorescence in situ hybridization (FISH) using genomic probes that span or flank the breakpoints is ideal for detecting this rearrangement in fine-needle aspiration (FNA) biopsies. To develop a set of probes, a bacterial artificial chromosome library was screened and the clones were mapped by fiber FISH. The probes were produced by the direct incorporation of fluorochrome-labeled nucleotides. The colocalization base FISH assay was applied to Cytospin preparations from FNA biopsies of lymph nodes from 26 patients with FL and 10 patients without FL. In those with FL, the percentage of cells with at least one IgH/BCL2 fusion signal ranged from 22% to 100% (mean, 63%), which was statistically significantly higher than that in FL-negative samples (mean, 2.7%). The probes demonstrated a significantly lower cutoff value (7%) in normal controls and effectively reduced the false-positive rate in FL-negative cases. These results were confirmed with fiber FISH assays on the same specimens. This interphase FISH assay is rapid and reliable for detecting rearrangements in the IGH/BCL2 gene, thereby aiding in the diagnosis of FL on FNA biopsy specimens.

Detection of bcl-2/J(H) translocation by polymerase chain reaction: a summary of the experience of the Molecular Oncology Survey of the College of American Pathologist

CONTEXT

The t(14;18)(q32;;t6q21) translocation, found in about 85% of follicular lymphomas, brings the bcl-2 gene on 18q21 under control of the immunoglobulin heavy-chain gene transcriptional regulatory elements on 14q32. Detection of this translocation in a clinical sample suspected of containing lymphoma can assist the pathologist in diagnosis and classification of lymphoma. Polymerase chain reaction is a technology that is frequently used to detect the t(14;18)(q32;q21) translocation (bcl-2/J(H)). This article reviews the utility of polymerase chain reaction testing for bcl-2/J(H) detection and summarizes the experience of participants in the Molecular Oncology Proficiency Survey of the College of American Pathologists from 1997 through 2000.

OBJECTIVE

To describe current practice and encourage improvement of bcl-2/J(H) testing in clinical laboratories.

DESIGN

Retrospective analysis of Molecular Oncology Proficiency Survey data.

PARTICIPANTS

Laboratory participants in the College of American Pathology Molecular Oncology Proficiency Survey.

RESULTS

Twenty-four well-characterized specimens were sent to participants, of which 6 contained bcl-2/J(H) major breakpoint region translocations. Eight hundred nineteen major breakpoint region and 323 minor cluster region determinations were performed, with an overall correct response rate of 91% and 94%, respectively. No significant difference in correct response could be found for frozen versus paraffin-embedded tissues. Many laboratories did not know their assay sensitivity.

CONCLUSION

Overall performance was good; however, there was great variability in the methods reported and lack of knowledge of the limits of detection was common. Continued participation in external quality control programs, such as the Molecular Oncology Survey; dissemination of information that impacts on test performance; and technical recommendations from the molecular diagnostics community are critical for improved testing for bcl-2/J(H).