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

BACKGROUND: Diagnosing lymphoproliferative disorders on fine-needle aspiration (FNA) can be challenging due to variable cellularity and lack of architecture. Ancillary studies often are required for diagnosis. Follicular lymphoma (FL) is characterized by a monoclonal B-cell proliferation with coexpression of CD19/CD10 and a t(14;18)(q32;q21) reciprocal translocation, resulting in the immunoglobulin heavy chain/BCL-2 fusion gene. These features also can be found, with much lower frequency, in diffuse large B-cell lymphoma (DLBCL) of follicle center cell origin. The objective of the current study was to compare the accuracy in detecting FL and DLBCL of follicle center cell origin by interphase fluorescence in situ hybridization (I-FISH) versus flow cytometry immunophenotyping (FCM) on FNAs. METHODS: Concurrent testing by FISH for t(14;18)(q32;q21) and FCM was performed on 84 FNAs, including 40 FLs and 44 non-FLs (de novo DLBCLs, mantle cell lymphomas, small lymphocytic lymphomas/chronic lymphocytic leukemias [SLLs/CLLs], small B-cell lymphomas, and reactive lymphoid hyperplasias). The final diagnosis was rendered based on the combined information from cytomorphology, FCM, FISH, immunocytochemical staining for Ki-67, monoclonality for kappa and lambda light chains, and, if available, corresponding tissue biopsy, cytogenetic analysis, and polymerase chain reaction analysis. RESULTS: Among 40 FLs, FISH produced positive results for the t(14;18) translocation in 85.0%, negative results in 7.5%, and insufficient results in 7.5%; whereas, with FCM, 75% of cases exhibited a CD19-positive (CD19+)/CD10+ population (28 monoclonal, 2 nonclonal), 12.5% of cases exhibited a CD19+/CD10-negative population (3 monoclonal, 2 nonclonal), and 12.5% of cases were insufficient. All of nonclonal results from FCM and all of the insufficient results from FCM analysis exhibited unequivocal t(14;18) translocation by FISH. In contrast, the three negative results and the three insufficient results from FISH were monoclonal and CD19+/CD10+ on FCM. The results from FISH and FCM were concordant in 75% cases. Of 44 non-FLs, FISH produced positive results for the t(14;18) translocation in 5 DLBCLs and 2 SLLs/CLLs. The latter showed single fusion signals just above the cutoff level. All cases in the non-FL group that failed to show clonality or had insufficient results from FCM were DLBCLs. Among 17 DLBCLs, FISH detected a t(14;18) translocation in 29.4%, whereas FCM demonstrated a CD19+/CD10+ population in 23.5%. CONCLUSIONS: I-FISH for the t(14;18)(q32;q21) translocation provided high overall accuracy in detecting FLs on FNAs. This test can be used for diagnosing or monitoring FL on FNAs when cellularity is limited or when FCM results are noncontributory. For detecting a follicle center cell origin in DLBCLs, I-FISH for the t(14;18) translocation appeared to be slightly more sensitive than FCM for the CD19+/CD10+ immunophenotype.     

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.     

Is t(14;18)(q32;q21) a constant finding in follicular lymphoma? An interphase FISH study on 63 patients.

The translocation (14;18)(q32;q21) is the hallmark of follicular lymphoma (FL). However, conventional cytogenetics and PCR techniques fail to detect it in at least 10% of cases. In order to evaluate the true incidence of this translocation in FL, we analyzed 63 patients with FL, and 17 patients with diffuse large cell lymphoma (DLCL) corresponding to suspected FL transformations using interphase fluorescence in situ hybridization (FISH). Colocalized signals related to the translocation were observed in 19-92% of cells (median = 51%), corresponding to positivity over the threshold in all (63/63) cases. Similarly, 16/17 possibly secondary DLCL displayed the translocation. Although some cytogenetic changes might be missed by this FISH assay (such as rare insertion, or translocations with other chromosomal partners), our results stress t(14;18)(q32;q21) as an almost constant finding in FL. Our sensitive interphase FISH assay should be of great value to define FL more accurately, namely in patients included into therapeutic trials. Furthermore, this approach could be of interest in (re)defining some types of FL, especially the grade 3 FL which frequently lack t(14;18).     

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.     

Two patterns of chromosomal breakpoint locations on the immunoglobulin heavy-chain locus in B-cell lymphomas with t(3;14)(q27;q32): relevance to histology

The t(3;14)(q27;q32) is the most common translocation involving BCL6 in B-cell lymphoma. Although this translocation was predominantly associated with diffuse large B-cell lymphoma (DLBCL), recent studies have shown that it can also be found in follicular lymphomas (FL), often associated with a large cell component. To further investigate the relationship that might exist between this translocation and the phenotype of the tumors, we studied 34 lymphomas with a t(3;14)(q27;q32). Twenty cases were DLBCL, 14 FL and most cases, regardless of histology, were negative for the expression of CD10 (26/32, 81%). We identified the IGH switch region involved in the translocation for 32 cases. Our data indicate that in DLBCL most breakpoints involve the switch mu (17/19; 89%), whereas in FL most involve a switch gamma (9/13; 70%) (P=0.0016, Fisher's exact test). This correlation between the histology and the structure of the translocated allele suggests that the lymphomas with Smu and Sgamma translocations may originate from different cells, or that the substituted regulatory regions that come to deregulate BCL6 may affect the presentation of the disease.     

FISH is better than BIOMED-2 PCR to detect IgH/BCL2 translocation in follicular lymphoma at diagnosis using paraffin-embedded tissue sections

The most common genetic aberration in follicular lymphoma (FL) is the t(14;18)(q32;q21) translocation that juxtaposes the antiapoptotic BCL2 gene with the promoter of the immunoglobulin heavy chain (IgH) gene. Our aim was to test the usefulness of two different techniques, fluorescence in situ hybridization (FISH) and PCR to detect t(14;18) in FL at diagnosis in paraffin-embedded tissue sections. A total of 51 patients diagnosed of FL were analyzed. FISH was performed with dual color dual fusion commercial probes (VYSIS) and in PCR experiments, the BIOMED-2 primers covering MBR, mcr and 3'MBR regions were applied. FISH showed positivity for the IgH/BCL2 translocation in 96% of patients and PCR in 59% of patients. FISH was able to detect variant translocations involving light chain Ig, or showing variant patterns such as deletions of the IgH portion involved in translocation. In 4% of cases, the IgH/BCL2 translocation was not detected by any of the two techniques tested. Our results show that FISH represents the best technique to detect t(14;18) at diagnosis.     

Cryptic IGH/BCL2 rearrangements with variant FISH patterns in follicular lymphoma

Follicular lymphoma (FL) is one of the most common non-Hodgkin lymphomas (NHL). Translocation t(14;18)(q32;q21) involving IGH and BCL2 genes represents its genetic hallmark. We present six cases of a series of 75 well diagnosed FL patients in which variant fluorescence in situ hybridization (FISH) patterns for this rearrangement were found. Moreover, G-banding cytogenetics and polymerase chain reaction (PCR) methods were unable to detect t(14;18)(q32;q21). According to our results, FISH is the best technique to define variant rearrangements of IGH/BCL2 genes and is important to detect it in cases with non-conclusive FL characteristics to avoid misdiagnosis with other NHL.     

Deregulation of FCGR2B expression by 1q21 rearrangements in follicular lymphomas.

We report here the molecular cloning and characterization of a t(1;14)(q21;q32) in a follicular lymphoma (FL) with an unusual BCL2 aberration. Fluorescence in situ hybridization (FISH) and Southern blot analysis of tumor cells identified the translocation breakpoint within the 5' switch region of IGHG (Sgamma). We cloned the chimeric breakpoint region approximately 1.5 kbp downstream from the HindIII site of 5'Sgamma2 on chromosome 14q32 and identified a 360-bp novel segment with homology to the CpG island clone 11h8. Two BAC clones containing this sequence were isolated and mapped to 1q21 by FISH. BAC 342/P13 contained sequences homologous to Fcgamma receptors 2A, 3A, 2B, 3B, and a heat shock protein gene HSP70B. The translocation brought the Sgamma2 region of a productive IGH allele 20 approximately 30 kbp upstream of FCGR2B. As a result of the translocation, the b2 isoform of FCGR2B was overexpressed in the tumor. Screening of a panel of 76 B-cell lymphomas with 1q21-23 cytogenetic aberrations by Southern blot analysis using breakpoint probes identified an additional FL with a t(14;18)(q32;q21) and a breakpoint in the FCGR2B region. These results suggest that FCGR2B may be deregulated by 1q21 aberration in BCL2 rearranged FLs and possibly play a role in their progression.     

Analysis of 14q+ Derivative Chromosomes in Non-Hodgkin's Lymphomas by Fluorescence In-Situ Hybridization

The most common chromosomal abnormality observed in non-Hodgkin's lymphomas (NHL) involves the structural alteration of the q arm of chromosome 14. It is not always possible, however, to fully analyse such derivative chromosomes by Giemsa-banding. Therefore, we have applied the fluorescence in-situ hybridization (FISH) technique of chromosome painting to elucidate the origins of the der(14) chromosomes in 8 cases of NHL. In 2 NHL the der(14) appeared to be the product of the t(14;18)(q32;q21) translocation, but were not accompanied by the reciprocal der(18) chromosome. In 3 cases the breakpoint was at 14q32 but the translocated material appeared not to be from chromosome 18 and in 2 cases the breakpoint was centromeric to 14q32. One case with a t(14;18)(q32;q21) was also analysed as a control. Dual painting was carried out with paints for chromosome 14 and either chromosome 3, 8, 10, 11, 18 or 19. In the control and 2 other cases the translocated material was demonstrated to be from chromosome 18, in two cases it was from chromosome 3 and in 1 case there was an unusual insertion of chromosome 11 material. We were unable to identify the origins of the translocated material in 1 NHL and in the final case the apparent der(14) was demonstrated not to contain chromosome 14 material. These data demonstrated the utility of the FISH technique for analysing malignant cell karyotypes, and in particular indicated the potential of this approach for identifying cases containing putative NHL associated oncogenes that may have been translocated adjacent to the immunoglobulin locus at 14q32.     

黏膜相关淋巴样组织淋巴瘤分子遗传学研究进展

  近年来对MALT淋巴瘤的研究主要集中在基因和染色体异常。除早期发现的t(11;18)(q21;q21)／API2-MALT1融合基因外,还发现t(1;14)(p22;q32)／BCL10-IgH或t(1;2)(p22;p12)／BCL10-IgLκ;t(14;18) (q32;q21)／IgH-MALT1;t(3;14)(p14.1;q32)／FOXP1-IgH以及BCL6基因异常。另外,对MALT淋巴瘤和由此转化的弥漫大B细胞淋巴瘤的关系也逐渐明确,发现了独特的或二者相互重叠的基因异常。这些分子遗传学的研究,有助于了解MALT淋巴瘤的发病机制,也有助于早期诊断和合理治疗。     

Characterization of IGH rearrangements in non-Hodgkin's B-cell lymphomas by fluorescence in situ hybridization

Rearrangements involving the IGH gene have been identified in about 50% of non-Hodgkin's B-cell lymphomas (NHL) and correlated to clinical relevant subgroups. However, the detection rate varied greatly with the technique used. The incidence of IGH rearrangements was analyzed using several fluorescence in situ hybridization (FISH) techniques on metaphases obtained from 57 patients with nodal NHL. An IGH rearrangement was identified in 42 cases (73.7%). A t(14;18)(q32;q21) was found in 17 of the 20 follicular lymphomas (85%) studied and a t(11;14)(q13;q32) in 10 of the 11 mantle cell lymphomas (91%). IGH rearrangements were identified in 12 of the 26 diffuse large B-cell lymphomas (46%), including 5 t(14;18)(q32;q21) and 2 t(3;14)(q27;q32). Conventional cytogenetics was uninformative in several cases. However, the complemented analysis using Multi-FISH and/or chromosomal whole paint enabled the characterization of complex IGH translocations in follicular lymphomas and mantle cell lymphomas and the identification of all the chromosomal partners involved in the IGH rearrangement in diffuse large B-cell lymphomas. This study shows the interest of using metaphase FISH in addition to conventional cytogenetics. Following banding techniques, FISH with the IGH dual color probe could be the first approach in NHL, after which chromosome painting and M-FISH could be used to identify the chromosomal partner involved in the IGH rearrangement.     

Establishment and comprehensive analysis of a new human transformed follicular lymphoma B cell line, Tat-1.

A spontaneously EBV transformed follicular lymphoma (FL) cell line, Tat-1, was established from the lymph node biopsy specimen of a patient with B cell FL, grade 1 in transformation to high grade disease. Tat-1 cells expressed lymphoid markers and developed tumor masses in immunodeficient mice. Bcl-2, Bcl-X(L), Bax and p53 protein expression was revealed by Western blotting. Flow cytometric analysis confirmed P-gp expression. Cytogenetically, the Tat-1 cell line showed identical chromosomal alterations to that of the initial biopsy specimen, among which the most notable were the t(14;18) typical of FL and additional abnormalities involving chromosomes 1, 8 and 13. Multicolor FISH analysis delineated all abnormalities, including a t(1p;8q), a der(8)(8q24::14q32::18q21) and a der(13)(13q32::8q24::14q32::18q21). Further FISH investigations using a locus-specific probe cocktail containing c-myc, IgH and bcl-2 revealed fusion of these three loci on the derivatives 8 and 13, in addition to the derivative 14 IgH/bcl-2 fusion and an extra copy of c-myc on derivative chromosome 1. These results demonstrate an additional example of the deregulation of bcl-2 and c-myc expression through recombination with a single IgH enhancer region. The unusual molecular features of the Tat-1 cell line render it a unique tool for studies focused on cytogenetic alterations, expression of multidrug resistance phenotype and expression of anti-apoptotic proteins in FL.     

Translocations t(11;18)(q21;q21) and t(14;18)(q32;q21) are the main chromosomal abnormalities involving MLT/MALT1 in MALT lymphomas.

The recently discovered MLT/MALT1 gene is fused with the API2 gene in the t(11;18)(q21;q21), which characterizes about one-third of MALT lymphomas. In order to screen for variant translocations and amplifications of MLT/MALT1, we have developed a novel, undirected two-color interphase fluorescence in situ hybridization (FISH) assay with two PAC clones flanking MLT/MALT1. This assay was applied to 108 marginal zone B-cell lymphomas (MZBCLs), including 72 extranodal MALT lymphomas, 17 nodal, and 19 splenic MZBCL. In 19 MALT lymphomas (26%), but in none of the nodal or splenic MZBCL, separated hybridization signals of the MLT/MALT1 flanking probes, were found. Further FISH analyses showed that 12 of these 19 cases displayed the classical t(11;18) and the remaining seven cases revealed the novel t(14;18)(q32;q21), involving the MLT/MALT1 and IGH genes. The frequency at which these translocations occurred varied significantly with the primary location of disease. The t(11;18) was mainly detected in gastrointestinal MALT lymphomas, whereas the t(14;18) occurred in MALT lymphomas of the parotid gland and the conjunctiva. Amplification of MLT/MALT1 was not observed in any of the lymphomas analyzed. We conclude that the translocations t(11;18)(q21;q21) and t(14;18)(q21;q32) represent the main structural aberrations involving MLT/MALT1 in MALT lymphomas, whereas true amplifications of MLT/MALT1 occur rarely in MZBCL.     

Detection of 14q32.33 translocation and t(11;14) in interphase nuclei of chronic B-cell leukemia/lymphomas by in situ hybridization

Abnormalities of chromosome 14 involving band q32.33 are among the most commonly observed cytogenetic alterations in B-cell malignancies. To assess the incidence and pathogenetic implications of 14q32.33 translocation in chronic B-cell leukemia/lymphomas, we performed fluorescence in situ hybridization (FISH) analysis with variable region (V_H) and gamma constant region (Cγ) gene probes in 37 patients with these disorders. Chromosome 14q32.33 translocation was detected in 2 of 18 patients with chronic lymphocytic leukemia (CLL), 1 of 2 with CLL of mixed cell types (CLL/PL), 1 of 2 with pro-lymphocytic leukemia (PLL), 5 of 6 with leukemic mantle-cell lymphoma (MCL), 2 of 7 with splenic B-cell leukemia/lymphoma of possible marginal zone origin (SBLL) and 2 with leukemic follicular lymphoma (FL). To further characterize 14q32.33 translocations in these patients, we developed a new procedure using double-color FISH with PRAD1, BCL2, V_H and Cγ gene probes. Chromosome t(11;14) was detected in 1 patient with CLL/PL, 1 with PLL and 5 with MCL. Chromosome t(14;18) was detected in 2 patients with FL. In a PLL patient with t(11;14), the cosmid CPP29 containing the PRAD1 gene and its 5′-flanking region split and co-localized with both Cγ and V_H gene probes, thus spanning the breakpoint. In CLL and SBLL patients, donor chromosomes were other than chromosomes 2, 11, 18 and 19, suggesting the involvement of a novel oncogene(s) in the pathogenesis of these diseases. Interphase FISH rapidly detected 14q32.33 translocation, t(11;14) and t(14;18) in B-cell malignancies with low mitotic activity at the single-cell level, facilitating the correlation of the molecular features of these translocations with clinical characteristics. Int. J. Cancer 72:31–38, 1997. © 1997 Wiley-Liss Inc.     

Chromosome abnormalities in malignant lymphoma in patients from Kurashiki: histological and immunophenotypic correlations

Clonal chromosomal abnormalities were found in tumor tissue of 43 (84%) of 51 patients with non-Hodgkin's lymphoma (B-cell, 32; T-cell, 15) from an adult T-cell leukemia/lymphoma-nonendemic area in western mainland Japan. Four tumors were tetraploid, and the other 39 had a chromosome number in the diploid range. Trisomies 3, 5, 7, 18, and X, monosomy 13, and loss of an X in female and a Y in male were found in more than three patients each. Structural abnormalities in arms 1p, 1q, 2q, 3q, 13q, 14q, and 18q were found in eight or more patients each. Clustering of breaks occurred in 3q25-29 (ten patients, nine of whom with a B-cell tumor), 11q13 (five patients), dir dup(12)(q13-15----q21-24) (four patients), 14q32 (12 patients), and 18q21 (seven patients). The 14q32 translocations were all associated with B-cell tumors. t(8;14) was seen in a small noncleaved cell lymphoma, t(11;14)(q13;q32) in one follicular and three intermediately differentiated lymphocytic lymphomas, and t(14;18)(q32;q21) in two follicular lymphomas and one diffuse small cleaved cell tumor. The translocation partner of 14q could not be determined in the other four patients, three of whom had der(18)t(18;?)(q21;?). The seven 18q21 abnormalities, including a novel translocation t(2;18)(p11;q21.3), all occurred in B-cell tumors; even in the absence of t(14;18), they were closely associated with lymphomas of follicular center cell origin (six of seven).     

t（14；18）阴性滤泡性淋巴瘤的分子遗传学机制及研究进展

滤泡性淋巴瘤（FL）是生发中心起源的低级别B细胞非霍奇金淋巴瘤。最具特征性的遗传学改变是染色体14q32上的免疫球蛋白重链基因（IgH）和染色体18q21上的Bcl-2基因的平衡转位,形成t（14;18）（q32;q21）。此转位使Bcl-2蛋白过度表达。在功能上延长了细胞的生存时间并导致FL的形成。t（14;18）并不是出现于所有FL病例中,大约90%的FL存在t（14;18）,其余的FL未能检测到该转位。t（14;18）的存在与否与滤泡性淋巴瘤的发生和发展密切相关。      

Translocation t(14;18)/IGH‐BCL2 in gastrointestinal follicular lymphoma

BACKGROUND:

Chromosomal translocation t(14;18)(q32;q21) involving the immunoglobulin heavy chain gene (IGH) and the BCL2 gene (t[14;18][q32;q21]/IGH‐BCL2) is present in 60% to 90% of nodal follicular lymphomas. To the authors' knowledge, the prevalence and clinical significance of this translocation have not been examined previously in gastrointestinal follicular lymphomas.

METHODS:

Clinicopathologic and molecular features were investigated in 48 patients who had gastrointestinal follicular lymphoma. The site of involvement was the duodenum in 54% of patients, the jejunum in 52%, the ileum in 52%, the stomach in 29%, and the colorectum in 15%. The presence of the t(14;18)/IGH‐BCL2 translocation was detected by interphase fluorescence in situ hybridization.

RESULTS:

Treatment modalities included surgical resection (n = 16), rituximab plus chemotherapy (n = 13), rituximab alone (n = 6), antibiotics (n = 5), and watchful waiting (n = 8). Complete remission (CR) of lymphoma was achieved in 31 patients (65%). The overall survival and event‐free survival rates after 5 years were 93% and 68%, respectively. The t(14;18)/IGH‐BCL2 was detected in 39 patients (81%). The involvement of multiple sites (69% vs 0%), manifestation of the lymphomatous polyposis type (72% vs 22%), and histologic grade 1 or 2 tumors (92% vs 56%) were more frequent in the t(14;18)‐positive group than in the negative group. In addition, the CR rate was lower in the t(14;18)‐positive group than in the negative group (56% vs 100%; P = .0179), and a trend was observed toward poorer event‐free survival in the positive group (P = .089).

CONCLUSIONS:

The t(14;18)/IGH‐BCL2 chromosomal translocation occurred frequently in gastrointestinal follicular lymphomas. The current results indicated that this translocation may be a predictor of an adverse clinical course. Cancer 2011. © 2010 American Cancer Society.     

Characterisation of BCL2-JH rearrangements in follicular lymphoma: PCR detection of 3' BCL2 breakpoints and evidence of a new cluster.

Follicular lymphomas (FL) are closely associated with a t(14;18)(q32;q21) translocation, leading to a bcl2 protein over-production. This translocation probably constitutes a very early step in the development of the disease. Besides the cytogenetic assay, t(14;18) detection can be achieved using either Southern blot or polymerase chain reaction (PCR). Since 1990, several publications have reported discrepancies between the results of cytogenetic and molecular analysis of t(14;18). Using methods able to explore long DNA fragments, several authors reported breakpoints located outside the usual breakpoint regions. However, these techniques cannot be easily used in routine. The aim of this study was to develop a simple PCR assay to amplify rearrangements usually not detected in FL. We selected a group of 83 patients with a t(14;18) on cytogenetic analysis: using usual probes and primers, 54/83 (65.1%) showed a MBR rearrangement, 7/83 (8.4%) were mcr positive and 22/83 (26.5%) remained negative. Among these 22 rearrangements, nine could be detected using this new PCR assay. Four breakpoints were located in a 20 bp area suggesting a recurrent breakpoint cluster close to an Alu repetitive sequence. Finally, remaining negative cases (13/83, 15.6%) suggest that other breakpoints are located between the MBR and mcr regions.