The detection of specific gene rearrangements in non-Hodgkin's lymphoma using the polymerase chain reaction

Demonstration of Chimeric DNA of bcl-2 and Immunoglobulin Heavy Chain in Follicular Lymphoma and Subsequent Hodgkin Lymphoma from the Same Patient

We performed single cell polymerase chain reaction (PCR) amplification of the t (14 ; 18) translocation from paraffin embedded sections in a case of follicular lymphoma (FL) with subsequent development of Hodgkin lymphoma (HL). The lymphoma cells of FL were positive for CD20, CD10 and BCL-2, and negative for CD3, CD30 and CD15. Hodgkin and Reed-Sternberg (HRS) cells of HL were positive for CD20, CD30 and CD15, and negative for CD3 and CD10. EBER-1 RNA in situ hybridization failed to stain with both lymphomas. HRS cells manipulated and FL cells micro-shaved from individual neoplastic follicles were subjected to single-cell PCR. The t (14 ; 18) translocation, a chimeric DNA containing portions of the bcl-2 and the immunoglobulin heavy chain (IgH) genes, was amplified from four of 27 isolated HRS cells and two individual FL follicles. All t (14 ; 18) PCRs yielded products of the same size, and an identical nucleotide sequence including the t (14 ; 18) translocation was found in both FL and HRS samples. Thus, the data demonstrate the common clonal origin of FL cells and HRS cells in subsequent HL, and that both FL and HL were derived from germinal center B cells with the t (14 ; 18) translocation.

Detection of the bcl-2 t(14;18) translocation and proto-oncogene expression in primary intraocular lymphoma

PURPOSE

Primary intraocular lymphoma (PIOL) is a diffuse large B cell lymphoma that initially infiltrates the retina, vitreous, or optic nerve head, with or without central nervous system involvement. This study examined the expression of the bcl-2 t(14;18) translocation, the bcl-10 gene, and high expression of bcl-6 mRNA in PIOL cells.

METHODS

Microdissection and PCR analysis were used to examine vitreous specimens in patients with PIOL for the presence of bcl-2 t(14;18) translocations, the bcl-10 gene, and expression of bcl-6 mRNA. A medical record review was also conducted to determine whether the bcl-2 t(14;18) translocation correlated with prognosis.

RESULTS

Forty of 72 (55%) PIOL patients expressed the bcl-2 t(14;18) translocation at the major breakpoint region. Fifteen of 68 (22%) patients expressed the translocation at the minor cluster region. The bcl-10 gene was detected in 6 of 26 (23%) patients, whereas 4 of 4 (100%) PIOL patients expressed higher levels of bcl-6 mRNA compared with inflammatory lymphocytes. An analysis of clinical outcome in 23 PIOL patients revealed no significant association between bcl-2 t(14;18) translocations and survival or relapse. However, patients with the translocation were significantly younger.

CONCLUSIONS

PIOL has unique molecular patterns of bcl-2, bcl-10, and bcl-6 when compared with other systemic lymphomas. This study lays the foundation for future studies aimed at exploring the genotypic classification of PIOL based on the quantitative molecular framework of gene expression profiling, with the goal of providing useful adjuncts to the pathologic diagnosis of this complex disease.

Detection of BCL2-IGH Using Single-Round PCR Assays

The translocation t(14;18) resulting in fusion of the BCL2 and the immunoglobulin heavy chain genes (BCL2-IGH) is present in 80% to 90% of follicular lymphomas and 20% to 30% of diffuse large B-cell lymphomas. Polymerase chain reaction (PCR) analysis for the translocation products suffers from low analytic specificity. As a result, either nested PCR or probe hybridization is required to aid in the identification of the specific translocation products. These added procedures are undesirable in clinical laboratories because nested procedures increase the possibility of contamination and probe hybridization increases assay turnaround time. To simplify the BCL2-IGH assay procedure, we attempted to eliminate the nonspecific PCR products by optimizing the annealing temperatures of the PCR assays using a gradient thermocycler. We showed that gradually increasing the annealing temperature from 55 degrees C to 67 degrees C significantly enhanced the intensity of the specific PCR products while eliminating the nonspecific ones. We compared the simplified procedure with a PCR-probe hybridization method on 68 patient specimens. The simplified procedure had increased analytic and diagnostic specificities with comparable sensitivities. With significantly improved analytic specificity, one round of PCR is sufficient to detect the BCL2-IGH gene rearrangements without further confirmation.

Detection of t(14;18) in follicular lymphoma by dual-color fluorescence in situ hybridization on paraffin-embedded tissue sections

We studied the incidence of t(14;18)(q32;q21) in 54 patients with follicular lymphoma (FL) by dual-color fluorescence in situ hybridization on paraffin-embedded tissue sections (tissue-FISH) using probes for BCL2 and immunoglobulin heavy chain (IGH) genes. The t(14;18) was detected in 28 (56%) of 50 patients, who were successfully analyzed. On the other hand, BCL2 protein expression was detected in 45 (83%) of 54 patients evaluated by immunohistochemical staining. There was a discrepancy between t(14;18) and BCL2 expression. The absence of t(14;18) was associated with disease-free survival (P=0.02). There was no statistical difference, however, in overall survival and failure-free survival between the t(14;18)-positive and -negative groups. Tissue-FISH should be of great value to detect t(14;18) in FL because this method enabled us to demonstrate specifically t(14;18)-positive individual cells in neoplastic follicles on paraffin-embedded tissue sections. Furthermore, tissue-FISH can be applied to small specimens obtained from endoscopic biopsy or specimens obtained more than 10 years ago. We validated the usefulness of tissue-FISH as a diagnostic procedure and retrospective meta-analysis for malignant lymphoma.

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.

Analysis of immunoglobulin VH genes in CD10-positive diffuse large B-cell lymphoma

CD10, a proteolytic enzyme seen in germinal center cells and in the majority of follicular lymphomas, is occasionally expressed in diffuse large B-cell lymphomas (DLBCL). To clarify the origin and cellular characteristics of CD10-positive DLBCL, we analyzed 36 de novo cases of DLBCL for somatic mutations of the immunoglobulin heavy chain variable region (VH) genes and for their immunophenotypes. Expression greater than that of grade 2 Bcl-6 was observed in 11 of the 30 CD10-negative cases (37%) and in all six CD10-positive cases (100%; P < 0.05) without expression of CD5, CD23, cyclin D1, CD30 or CD138. The average mutation frequencies of the six CD10-positive and 30 CD10-negative DLBCL were 12.9 and 9.8%, respectively. The range of SM frequencies in CD10-positive DLBCL (9.52-18.06) was distinctly narrower than that observed for CD10-negative DLBCL (0.69-26.89). These findings seem to indicate that CD10-positive DLBCL, originating from germinal center B cells, is a genetically and immunophenotypically more homogeneous group than CD10-negative DLBCL. Furthermore, three extranodal lymphomas, in five of the six CD10-positive DLBCL, showed ongoing mutation, indicating that antigen-driven, high-affinity somatic mutation may play an important role in clonal expansion in CD10-positive DLBCL. All four extranodal cases of the six CD10-positive DLBCL showed ongoing mutation and/or bcl-2/JH rearrangement. This result suggests that the cell origin of extranodal CD10-positive DLBCL may be the same as that of follicular lymphomas.

Molecular detection of tumor cells at diagnosis invading the bone marrow and peripheral blood of patients with aggressive or indolent lymphomas

We studied tumor cell invasions of bone marrow and peripheral blood in patients with various types of advanced non-Hodgkin's lymphoma by amplifying complementarity determining region III using the polymerase chain reaction (PCR) method and developing patient-specific probes. After molecular engineering, we could detect tumor cells in bone marrow from seven of 11 cases and in peripheral blood from six of 11 cases, despite negative results in four cases studied morphologically. Indolent cases were more likely to yield positive results than aggressive cases. The reason may be different biological behaviors among the histological types.

Limitations of clonality analysis of B cell proliferations using CDR3 polymerase chain reaction

BACKGROUND/AIMS

Detection of clonal immunoglobulin heavy chain (IgH) rearrangements by the polymerase chain reaction (PCR) is an attractive alternative to Southern blotting in lymphoma diagnostics. However, the advantages and limitations of PCR in clonality analysis are still not fully appreciated. In this study, clonality was analysed by means of PCR, focusing in particular on the sample size requirements when studying extremely small samples of polyclonal and monoclonal lesions.

MATERIALS/METHODS

High resolution complementarity determining region 3 (CDR3) PCR was used to investigate the minimum number of cells and the amount of tissue required for the detection of a polyclonal population, both for fresh cells and formalin fixed, paraffin wax embedded tissue. Subsequently, frozen and paraffin wax embedded samples of 76 B cell lymphoproliferative disorders, 43 of which were tested by means of Southern blotting, were analysed to establish the sensitivity of this assay. These specimens included 12 chronic lymphocytic leukaemias (CLLs), nine mantle cell lymphomas (MCLs), 10 follicular lymphomas (FLs), and 45 mucosa associated lymphoid tissue (MALT) lymphomas. The specificity was tested on reactive lymph nodes (n = 19), tonsils (n = 4), peripheral blood lymphocyte fractions (n = 4), and biopsies with gastritis (n = 21).

RESULTS

In reactive tissue, 20 ng of high molecular weight DNA derived from 6.5-9 x 10(3) B cells was sufficient to obtain a polyclonal PCR result. With smaller amounts "pseudoclonality" could be induced. When using paraffin wax blocks, undiluted DNA isolated from tonsillar tissue of at least 1 mm2 was necessary to obtain a polyclonal pattern. The sensitivity required to detect clonality in paraffin wax embedded and frozen tissue by PCR for FL (40% and 60%, respectively) was lower than that for MALT lymphomas (60% and 86%, respectively), CLL (78% and 89%, respectively), and MCL (88% and 100%, respectively). PCR specificity was 96% and 100% for frozen and paraffin wax embedded tissue, respectively.

CONCLUSION

The minimum amount of template for CDR3 PCR is approximately 20 ng of high molecular weight DNA or 1 mm3 of B cell rich paraffin wax embedded normal tonsillar tissue, but care has to be taken to avoid pseudoclonality when low numbers of B cells are present. Duplicate or triplicate tests should be performed to avoid misinterpretation. The specificity of the PCR assay is almost 100%, whereas sensitivity depends on a combination of factors, such as lymphoma type and tissue fixation. Because frozen samples yield better results, obtaining fresh material for the PCR assay is recommended, especially when analysing FL and MALT lymphomas.

bcl-2 protein expression is associated with better prognosis in colorectal cancer

AIMS

To investigate the expression of bcl-2 in colorectal carcinoma and to examine its association with mediators of apoptosis (p53 and mdm-2), clinicopathological features and long-term outcome.

METHODS AND RESULTS

We determined by immunohistochemistry the expression of bcl-2 in 102 colorectal carcinomas with 10-year follow-up. In 66 of these cases in which we had previously assessed p53 status, no correlation was seen between bcl-2 and p53. The mdm-2 protein was not detected in any of the 66 cases. Cytoplasmic staining of the bcl-2 gene product was seen in the tumour cells of 22 cases (22%). Using a polymerase chain reaction technique we showed that overexpression of bcl-2 was not due to rearrangement of the bcl-2 gene. Expression of bcl-2 protein was related to tumour grade but was unrelated to patient age, sex, tumour site, tumour size or Dukes' stage. There was a trend towards increased survival in those whose tumours expressed bcl-2 protein (P = 0.055). When entered into a multivariate analysis, this survival difference was independent of tumour stage (P = 0.05).

CONCLUSIONS

These results suggest that bcl-2 expression in colorectal carcinoma is associated with a better long-term prognosis.

V(H) gene family utilization in different B-cell lymphoma subgroups

V(H) gene family specific polymerase chain reaction (PCR) amplification was performed in 87 B-cell lymphoma samples from 4 different subgroups. No apparent restriction in the VH gene usage was found in follicular lymphomas, lymphoplasmacytoid lymphomas or large B-cell lymphomas, whereas a biased VH1 utilization was shown in patients with chronic lymphocytic leukemia. Eleven of 18 chronic lymphocytic leukemia cases utilized the VH1 gene family, and nucleotide sequencing of the VH1 gene rearrangements revealed that a majority utilized the DP10 (51p1) germline gene, which has been reported to be strongly associated with autoimmune disease. No VH5 or VH6 rearrangements were amplified in the chronic lymphocytic leukemia subgroup, 2 gene families which previously have been found to be over-represented in these patients. In a high proportion (40%) of large B-cell lymphomas, VH gene family-specific PCR failed to amplify any rearrangement. Using primers hybridizing to the framework regions 2 and 3 and Southern blot analysis of the immunoglobulin heavy chain locus, clonal rearrangements were displayed in two-thirds of these PCR negative cases. However, the rearrangement status could not be elucidated in 5 of 35 patients with large B-cell lymphoma.

Geographic variance in the frequency of the t(14;18) translocation in follicular lymphoma: an Israeli series compared to the world

It has been suggested that differences in the frequency of the t(14;18) translocation in follicular lymphoma might explain ethno-geographic variation in the incidence of these tumors. We tested Israeli follicular lymphoma patients for the frequency of the t(14;18) translocation, and reviewed the published literature, comparing the frequency in our series with data from different parts of the world. Tissue specimens from 36 Israeli follicular lymphoma patients were tested for presence of the translocation by PCR amplification of the MBR breakpoint. Twenty-two of the 36 patients (61%) tested positive. A systematic search of the literature yielded 35 papers reporting the frequency of the t(14;18) translocation in follicular lymphoma. We analyzed cytogenetic data and molecular data separately. For each method, data were pooled from all studies within each of three geographical regions - USA, East Asia and Europe. Pooled data from cytogenetic studies show a low frequency of the translocation in the Far East (38%) compared to the USA (71%), with an intermediate frequency found in Europe (61%). Molecular studies show a similar frequency of the translocation in the Far East and Europe, significantly lower than the frequency in pooled data from American studies. The frequency in our Israeli series is relatively high, comparable to that detected in the USA. We suggest that the apparent geographical differences we describe are unlikely to be caused by a difference in the biology of the tumor, and are more likely due to technical and methodological factors. We conclude that it is unlikely that differences in the frequency of the t(14;18) translocation explain the difference in the epidemiology of lymphoma between East and West.

PCR analysis of IgH and BCL2 gene rearrangement in the diagnosis of follicular lymphoma in lymph node fine-needle aspiration. A critical appraisal

In order to improve the cytomorphologic diagnosis of malignant lymphoma on lymph node fine-needle aspiration (FNA), and to make a confident discrimination between low-grade follicular non-Hodgkin's lymphoma (NHL) and lymphoid hyperplasia, polymerase chain reaction (PCR) analysis was performed of the Ig CDR3 region and BCL2 breakpoint region in 25 nonselected cases of malignant lymphoma (17 NHL and 8 Hodgkin's disease [HD]) with histologic control, and 22 cases of lymph nodal hyperplasia with histologic and/or clinical control. Among lymphomas, IgH monoclonality was detected in 7 (77%) of 9 NHLs and BCL2 rearrangement in 3 (17.6%) of 17 NHLs, all of which were follicular centroblastic-centrocytic (FCBCC). Three BCL2/JH negative FCBCC cases were monoclonal for CDR3. Neither IgH monoclonality nor BCL2 rearrangement were found in HD. Among cytologically diagnosed lymphoid hyperplasias, one IgH polyclonal case was considered false-negative, being histologically diagnosed as lymphoplasmacytic NHL on the subsequent excisional biopsy. Another 4 cases (2 BCL2 rearranged and 2 monoclonal for IgH) were considered false-positive on the basis of histologic features or clinical control. These data indicate that the combined PCR analysis of IgH and BCL2 rearrangements can confirm a cytologic diagnosis of lymphoma in FNAs while, due to the occurrence of both false-positive and false-negative results, it is of limited value in the distinction between follicular lymphoma and lymphoid hyperplasia without morphologic or clinical support.

B-cell gene rearrangement in benign and malignant lymphoid proliferations of mucosa-associated lymphoid tissue and lymph nodes

The polymerase chain reaction (PCR) with polyacrylamide gel electrophoresis was used to study patterns of immunoglobulin heavy chain (IgH) gene rearrangement (GR) in formalin-fixed, paraffin-embedded specimens of lymphomas and reactive conditions of mucosa-associated lymphoid tissue (MALT) and lymph node. DNA amplification was performed directly on sections obtained from paraffin blocks. Five patterns of PCR products were observed: a single band, two or more discrete bands, smearing, a single band overlying a smear, and two or more bands over a smear. A pure polyclonal pattern (smear) was observed in all of the reactive lymph nodes but in only 15% of cases of Helicobacter pylori (HP) gastritis with lymphoid hyperplasia, 25% of cases of HP gastritis without lymphoid hyperplasia, and 37% of colonic specimens of various types. Patterns consisting of multiple bands with or without background smearing were common in gastritis, colitis, and gastric lymphomas. Single bands or dominant bands were present in all lymph node and salivary gland lymphomas, 12 of 14 cases of gastric lymphoma, and 17 of 20 cases of HP gastritis with lymphoid hyperplasia. These bands were reproducible in deeper sections from the same paraffin block or similar areas sampled in different blocks in all of the lymph node and salivary gland lymphomas, 11 of 12 gastric lymphomas, but only 1 of 17 cases of HP gastritis with lymphoid hyperplasia. Bands were also found in 3 of 20 cases of HP gastritis without lymphoid hyperplasia and 17 of 38 colonic specimens, but these were not reproducible. The complexity of patterns of IgH GR in acquired MALT compared with lymph nodes may be the result of a relative paucity of B-cell clones or preferential proliferation of B-cell clones with a limited area of distribution.

Clinical relevance of bcl-2(MBR)/J(H) rearrangement detected by polymerase chain reaction in the peripheral blood of patients with follicular lymphoma

We evaluated the prognostic role of peripheral blood polymerase chain reaction (PCR) assay for detection of the bcl-2(MBR)/J(H) rearrangement in 59 patients with follicular lymphoma (FL) treated at our centre since 1989. Thirty-five (59%) patients were bcl-2/J(H) positive and 24 (41%) were negative in the peripheral blood at diagnosis. Peripheral blood bcl-2/J(H) rearrangement detection at diagnosis had no relation to overall survival (OS) and time to progression (TTP). Peripheral blood PCR assay was performed post treatment in 17 patients who were bcl-2/J(H) positive at diagnosis. Fourteen of the patients (82%, 95% CI 56-96%) became bcl-2/J(H) negative. Nine of these patients were further analysed during follow-up and, after several months, circulating cells carrying the bcl-2/J(H) rearrangement reappeared in five of the nine patients. Peripheral blood clearance of bcl-2/J(H)-positive cells was correlated with better overall survival (log-rank P < 0.05) but not with TTP. Our data confirmed that bcl-2(MBR)/J(H) rearrangement detection by PCR at diagnosis is not a prognostic factor in follicular lymphoma. In our series, clearance of circulating bcl-2/J(H)-positive cells appeared to correlate with better overall survival. Post-treatment examination of the peripheral blood by PCR may have clinical relevance for prediction of the survival pattern of the patients.

Clinical significance of bcl-2 (MBR)/JH rearrangement in the peripheral blood of patients with diffuse large B-cell lymphomas

BACKGROUND

Approximately one-fourth of diffuse large B-cell lymphomas (DLCL) carry the bcl-2(MBR)/JH rearrangement caused by the t(14;18) translocation. The clinical significance of this rearrangement in patients with DLCL remains controversial. By polymerase chain reaction (PCR) we prospectively evaluated the prognostic relevance of the bcl-2 (MBR)/JH rearrangement present in circulating B-cells at the time of diagnosis.

MATERIALS AND METHODS

The bcl-2 (MBR)/JH rearrangement was analysed by a nested-PCR method in peripheral blood samples of 51 HIV-negative patients with previously untreated DLCL.

RESULTS

The bcl-2 (MBR)/JH rearrangement was detected in 16 cases (31%). Peripheral blood bcl-2 (MBR)/JH rearrangement detection by PCR at diagnosis was correlated with poor overall survival, lymphoma-specific survival and time to progression (log-rank P < 0.05). There was no statistically significant difference between the clinical characteristics at presentation of bcl-2/JH-positive and negative patients.

CONCLUSIONS

The peripheral blood is a readily accessible tissue for this type of analysis, and this study indicates that detection of the t(14;18) translocation at presentation in the blood of patients with DLCL may presage a poor prognosis.

Comparative preclinical study of three bone marrow purging methods using PCR evaluation of residual t(14;18) lymphoma cells

The t(14;18) chromosomal translocation occurring in most follicular lymphomas can be exploited by a Bcl2/JH polymerase chain reaction (PCR) to detect residual disease and to monitor the effectiveness of ex-vivo tumor cell immunological purging. We first demonstrated the 10(-5) Bcl2/JH PCR sensitivity with serial dilutions of OCY-LY8 lymphoma cell lines in normal mononuclear cells; and then the specificity and reproductibility of this technique by analysing follicular and non follicular lymphoma samples. With the Bcl2/JH PCR, we tested the efficiency of three marrow purging protocols with an experimentally contaminated bone marrow either treated by three anti-B cell monoclonal antibodies (mAb) followed by three rounds of rabbit complement or two rounds of immunomagnetics beads. Samples obtained after each purging were amplified by Bcl2/JH PCR and hybridized with PFL3 probe. We were able to produce a 2 to 3 log tumor cell reduction after three rounds of complement and a 4 to 5 log reduction after two rounds of beads. This study showed that it is feasible to use the Bcl2/JH PCR technique for residual cell lymphoma detection in patients undergoing intensive chemotherapy or BM transplantation. These results indicate that ex-vivo immunomagnetic BM purging is probably superior to complement mediated lysis for the eradication of B lymphoma cells from the marrow of patients undergoing autologous transplantation.

Optimal primer selection for clonality assessment by polymerase chain reaction analysis. III. Intermediate and high-grade B-cell neoplasms

Previous studies have reported that low-grade B-cell lymphoproliferative disorders have variable B-cell monoclonality detection rates by polymerase chain reaction (PCR) analysis. For instance, monoclonal B-cell populations from chronic lymphocytic leukemia/small lymphocytic leukemia and mantle cell lymphoma are most often readily amplified with a single primer pair, whereas follicular lymphomas and plasma cell neoplasms require alternative strategies to approach these higher diagnostic sensitivity standards. Because most published reports have not focused on the variation in PCR B-cell monoclonality detection among subtypes of intermediate and high-grade B-cell neoplasms, additional information is necessary to determine primer selection strategies and identify problematic tumor subtypes within this group. The current investigation, the third part in a series, was aimed at documenting the efficiency of B-cell monoclonality detection by PCR in 71 aggressive B-cell neoplasms of various types using a comprehensive approach. A predetermined panel of primer sets was used in an algorithmic fashion. Specifically, all samples were analyzed with the standard VH-FRIII/JH assay previously shown to have the highest efficiency of monoclonality detection within low-grade B-cell lymphoproliferative disorders. Negative samples were further evaluated with primer sets in the following order until a positive result was observed, or all primer sets were used: (1) bcl-2/JH, (2) VH-FRI family specific/JH, and (3) VH-FRI consensus/JH. Forty-three (61%) of the 71 B-cell neoplasms evaluated with VH-FRIII/JH showed monoclonal B-cell populations. Sequential use of the three reserve primer sets in samples negative with this initial primer pair resulted in an overall improvement in PCR detection from 61% to 82% (58 of 71 specimens) (P < .001). The VH-FRI family specific assay identified B-cell monoclonality in 11 (73%) of these 15 specimens and was the most productive reserve primer set. Individual categories exhibited the following initial (I) and final (F) PCR detection rates: acute lymphoblastic leukemia/lymphoblastic lymphoma, 11 specimens (I = 91% to F = 91%); small noncleaved cell lymphoma, 14 specimens (I = 79% to F = 86% [P > .25]); diffuse large cell lymphoma, 33 specimens (I = 52% to F= 85% [P < .005]) and large cell, immunoblastic lymphoma, 13 specimens (I = 38% to F = 62% [P < .01]). The authors have shown that comprehensive PCR analysis is capable of detecting B-cell monoclonality in a significant proportion of samples from each subtype of intermediate and high-grade B-cell neoplasm. The VH-FRIII/JH assay was an adequate initial primer set, but required augmentation with the reserve PCR assays to attenuate the false negative rate and improve diagnostic sensitivity. The B-cell clonality PCR assay is optimally used as a screening tool and when used in this fashion, the more laborious and time-consuming restriction fragment-Southern blot hybridization (RF-SBH) method for IgH gene rearrangement detection may be limited to a relatively small proportion of PCR-negative aggressive B-cell neoplasms.

A comparative study of the value of immunohistochemistry and the polymerase chain reaction in the diagnosis of follicular lymphoma

We have compared the value of immunohistochemical and polymerase chain reaction (PCR) techniques in distinguishing follicular lymphoma from follicular hyperplasia in formalin-fixed paraffin-embedded tissues of 41 follicular lymphomas, 15 reactive lymph nodes and 5 reactive tonsils. Immunohistochemistry demonstrated bcl-2 protein in the follicle centre cells of 97% of follicular lymphomas whereas monoclonal immunoglobulin light chain was detected in 83% of cases. Assessing the lowest proliferating follicle of each case by MIB-1 immunostaining, proliferation fractions in the lymphomas varied from 0.5% to 59% (mean 15.6%). Over 80% of lymphomas had proliferation fractions of less than 25%. PCR detected gene rearrangement either at the bcl-2 locus, or at the IgH locus, or at both loci in 32%, 44% and 61% of lymphomas, respectively. The follicle centre cells of the reactive lymph nodes and tonsils were all bcl-2 protein negative and polytypic for kappa and lambda light chains. Proliferation fractions of the lowest proliferating follicle in each reactive case ranged from 30.5% to 86.8% (mean 64.9%). Rearrangements of the bcl-2 or IgH loci were not detected in any reactive case. This study demonstrates that bcl-2 and light chain immunostaining are the most consistently helpful aids to diagnosing follicular lymphoma. A low proliferation fraction also indicates lymphoma but a high proliferation fraction does not exclude the diagnosis. Immunostaining with a combination of anti bcl-2 and MIB 1 antibodies is a sensitive and specific method for identifying follicular lymphoma, is technically simple to perform and easy to interpret. In occasional cases, where immunostaining gives equivocal results, PCR analysis can confirm lymphoma, but a negative result does not exclude the diagnosis.

The usefulness of a rapid PCR methodology to detect rearranged Ig heavy chain genes in lymphoproliferative disease in a diagnostic setting

Polymerase chain reaction (PCR) was used to amplify the DNA fragments of the framework 3 region (FR3) of the immunoglobulin heavy (IgH) chain genes, from the tissue of 66 patients with B-lymphoproliferative diseases and 74 patients with other malignant diseases, reactive or normal tissue. The assay performed with 77% sensitivity, 100% specificity and 89% efficacy. In addition, the PCR assay cost less than 25% of the cost performing Southern blot analysis of tumor DNA, which has been the test performed to date, and had a turn around time of 24 hrs rather than the 7-14 days required to obtain a result from Southern blot analysis. These results suggest that PCR analysis of B-cell lymphoproliferative disease is superior to Southern blot analysis, in the setting of a diagnostic laboratory.

Incidence and prognostic significance of t(14;18) translocation in follicle center cell lymphoma of low and high grade. A report from southern Sweden

BACKGROUND

The t(14;18)(q21;q32) is the most common recurrent genetic defect in follicle center cell lymphoma (FCC). Conflicting reports exist in regard to a possible prognostic significance for the translocation.

PATIENTS AND METHODS

In a single center, 102 patients with either low-grade (n = 50) or high-grade (n = 52) FCC (Kiel classification) and a median follow-up of 82 months were retrospectively studied to determine survival in relation to t(14;18) as shown by either PCR of the bcl-2 rearrangement in paraffinized tissue or karyotype analysis.

RESULTS

t(14;18) was detected in 30 of 50 (60%) low-grade FCC and in 12 of 52 (23%) high-grade FCC. The presence of the t(14;18) was not related to morphologic bone marrow involvement or other clinical parameters, but it was related to age: in low-grade FCC, patients with t(14;18) were an average of 17 years younger (p = 0.002) than those without the translocation. In the group with high-grade histology, 30% survived beyond 60 months regardless of t(14;18) status (p = 0.92). Patients with low-grade histology and t(14;18) fared better than those without, irrespective of age (p = 0.01). No significant difference in disease-free survival related to t(14;18) was found in either low- or high-grade FCC.

CONCLUSIONS

The incidence of t(14;18) is in accord with that of other European reports. T(14;18) does not define a prognostic subset of high-grade FCC, but is significantly correlated with a better survival in low-grade FCC. The association of t(14;18) with younger age and indolent lymphoma is perplexing in light of recent findings of an age-related increase in t(14;18) in normal subjects.

Molecular pathology of low grade malignant lymphomas

During the last ten years the combined efforts of pathologists and molecular biologists have helped define several new lymphoma diagnostic categories. In particular, the recognition of chromosomal translocations which have activated the BCL1 and BCL2 proto-oncogenes have strong associations with specific types of non-Hodgkin's malignant lymphomas such as mantle cell lymphoma and follicular center cell lymphoma, respectively. This review will attempt to summarize our current understanding regarding the contributions of BCL1 and BCL2 to lymphomagenesis and diagnosis.

Hodgkin's disease, follicular non-Hodgkin's lymphoma and a high grade B cell non-Hodgkin's lymphoma in the same patient

We report an unusual patient with a 21 year history of lymphoma of three different histological varieties: a low grade follicular non-Hodgkin's lymphoma, mixed cellularity Hodgkin's disease and a high grade B cell monocytoid non-Hodgkin's lymphoma.

Malignant lymphoma of the epididymis. A case report of bilateral involvement by a follicular large cell lymphoma

BACKGROUND

Malignant lymphoma of the testis involves the adjacent epididymis in approximately 60% of cases, but isolated epididymal lymphoma is rare.

METHODS

The file of a 34-year-old man was reviewed, and the biopsy material was studied by conventional morphology, immunohistochemistry, and polymerase chain reaction.

RESULTS

The patient presented with painless bilateral epididymal enlargement. Sequential bilateral epididymal biopsies revealed follicular lymphoproliferation with minimal involvement of one testis. Immunoglobulin M antibodies to the Coxsackie B4 virus were increased, and the lesions were interpreted as an atypical reactive process. Chemotherapy was not pursued. Four years after presentation, there was no evidence of local disease, but a 3-cm lesion involving the skin of the forehead developed. An excision biopsy revealed a large cell follicular lymphoma with features resembling the epididymal lesion. Analysis by polymerase chain reaction revealed a t(14-18) translocation in skin and epididymal lesions confirming that the epididymal lesions were also lymphomatous. Staging revealed no other site of disease. To date, the patient, who was treated with methotrexate chemotherapy, remains well 28 months after treatment.

CONCLUSIONS

Most lymphomas of the testis and epididymis occur in older men, have an intermediate or high grade, diffuse histology, disseminate early, and follow an aggressive clinical course. In contrast, this case is similar to the occasional reports of pseudolymphoma and follicular lymphoma that occur in younger men, are confined largely to the testis and epididymis, and have a good prognosis.

Optimal primer selection for clonality assessment by polymerase chain reaction analysis: I. Low grade B-cell lymphoproliferative disorders of nonfollicular center cell type

Recent polymerase chain reaction (PCR)-based studies focused on the detection of immunoglobulin heavy chain gene (IgH) rearrangements have suggested that clonal populations may be amplified more easily from certain categories of B-cell neoplasia than others and that primer makeup can be a critical factor in successful amplification. However, these particular reports contained relatively few low grade B-cell lymphoproliferative disorders of nonfollicular center cell type (LG-BLPD) and used only a limited panel of available primer sets for PCR amplification of monoclonal B-cell populations. To address this issue more extensively we evaluated 156 samples of LG-BLPD by the PCR to determine optimal primer selection in this setting. All cases were classified according to standard morphological and immunophenotypic criteria, with monoclonality documented by Ig light chain restriction analysis. The LG-BLPD included 33 cases of chronic lymphocytic leukemia (CLL), 57 cases of small lymphocytic lymphoma (SLL), 10 cases of atypical CLL, 32 cases of mantle cell lymphoma (MCL), 17 plasma cell neoplasms (PCNs), and seven cases of hairy cell leukemia (HCL). All primer sets included a 3' IgH joining region consensus primer, whereas the 5' IgH variable region (VH) primer was different in each set. The first-line panel included the following: Set 1, VH-framework III consensus primer, and Set 2, seven separate VH-framework I family-specific primers. A reserve panel of alternate VH consensus primers directed at framework II or III regions was used only when Set 1 showed no evidence of B-cell monoclonality.(ABSTRACT TRUNCATED AT 250 WORDS)

Optimal primer selection for clonality assessment by polymerase chain reaction analysis: II. Follicular lymphomas

Prior studies have shown variable success in amplification of monoclonal B-cell populations from follicular lymphomas (FLs) of germinal center cell origin using the polymerase chain reaction (PCR). We examined 60 FLs by the PCR to determine optimal primer selection for detection of clonal immunoglobulin heavy chain gene (IgH) rearrangements in this common group of B-cell lymphomas. Each primer set included a 3' IgH joining region consensus primer; the 5' primer was different in each reaction. The first-line panel included the following: Set 1, bcl-2 major breakpoint region (mbr) primer; Set 2, bcl-2 minor cluster region (mcr) primer; Set 3, IgH variable region framework III consensus primer; and Set 4, seven separate IgH variable region framework I family-specific primers. A reserve panel also was used. The efficiency of monoclonal B-cell population amplification differed among primer sets. The bcl-2-targeted primer pairs (Sets 1 and 2) were most efficient and amplified 42 (70%) of 60 cases. Of these, the mbr and mcr primer sets detected monoclonality in 38 and four cases, respectively. Set 3 amplified monoclonal B-cell in 38 and four cases, respectively. Set 3 amplified monoclonal B-cell populations in 31 (52%) cases and Set 4 detected similar populations in only 27 (45%) samples. When results from primer Sets 1, 2, and 3 were combined, 49 of 60 (82%) FLs showed evidence of B-cell monoclonality by the PCR. Three of the 11 negative cases were documented as monoclonal with primer Set 4, and three additional samples were amplified only with our reserve panel.(ABSTRACT TRUNCATED AT 250 WORDS)

Apparent absence of BCL-2 rearrangement in ten Saudi follicular lymphomas: A preliminary report

Specific chromosomal translocations are often found to be associated with distinct types of human neoplasms. The t(14;18) is considered to be a cytogenetic hallmark of the follicular lymphomas found mostly in American patients. This chromosomal translocation occurs through a 3' untranslated region (either major breakpoint region [mbr] or minor cluster region [mcr]) of the bcl-2 proto-oncogene in chromosome 18 and the JH region of the immunoglobulin (Ig) gene in chromosome 14. In the present study, the polymerase chain reaction (PCR) was used to detect a fusion DNA fragment generated from bcl-2/JH rearrangement either through mbr or mcr in 10 follicular lymphomas in Saudi Arab patients. Surprisingly, none of these cases showed any evidence of bcl-2 gene rearrangement through mbr or mcr. The absence of usual bcl-2/JH recombination in Saudi follicular lymphomas is intriguing and may suggest that the occurrence and mode of bcl-2 gene rearrangement in this lymphoma varies in different patient populations.