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.     

Genome-wide array-based comparative genomic hybridization of diffuse large B-cell lymphoma: comparison between CD5-positive and CD5-negative cases

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma and exhibits aggressive and heterogeneous clinical behavior. To genetically characterize DLBCL, we established our own array-based comparative genomic hybridization and analyzed a total of 70 cases [26 CD-positive (CD5+) DLBCL and 44 CD5-negative (CD5-) DLBCL cases]. Regions of genomic aberrations observed in >20% of cases of both the CD5+ and CD5- groups were gains of 1q21-q31, 1q32, 3p25-q29, 5p13, 6p21-p25, 7p22-q31, 8q24, 11q23-q24, 12q13-q21, 16p13, 18, and X and losses of 1p36, 3p14, 6q14-q25, 6q27, 9p21, and 17p11-p13. Because CD5 expression marks a subgroup with poor prognosis, we subsequently analyzed genomic gains and losses of CD5+ DLBCL compared with those of CD5-. Although both groups showed similar genomic patterns of gains and losses, gains of 10p14-p15 and 19q13 and losses of 1q43-q44 and 8p23 were found to be characteristic of CD5+ DLBCL. By focusing on the gain of 13q21-q34 and loss of 1p34-p36, we were also able to identify prognostically distinct subgroups among CD5+ DLBCL cases. These results suggest that array-based comparative genomic hybridization analysis provides a platform of genomic aberrations of DLBCL both common and specific to clinically distinct subgroups.     

Follicular lymphoma without t(14;18) and with BCL-6 rearrangement: a lymphoma subtype with distinct pathological, molecular and clinical characteristics.

Translocations involving the BCL-6 gene are frequently observed in diffuse large B cell lymphoma, but have rarely been reported in follicular lymphoma (FL). We studied a distinct cohort of FLs with a 3q27/BCL-6 gene rearrangement, but lacking the t(14;18) translocation. In 13/15 cases, translocations involved the 3q27 and the 14q32 regions. All cases displayed a marked follicular growth pattern and, in some instances, a monocytoid component. Tumor cells were CD5(-) CD20(+) CD23(-) CD43(-) BCL-6(+), and in the main CD10 negative (n = 10, 71%) and BCL-2 negative (n = 11, 78%). When compared to 20 typical t(14;18)(+) FLs, the presence of large follicles (P = 0.01) and a CD10(-)/BCL-2(-) phenotype were more frequently observed (P = 0.001) in our cohort. Clonal mutations arising in the BCL-6 first intron were observed in 5/7 cases with evidence of intraclonal heterogeneity, consistent with a germinal center origin. No significant difference was found in comparison to t(14;18)(+) FL regarding age, sex, performance status, bone marrow involvement or overall survival. However, in the 3q27(+) FL group, a stage III/IV disease and a bulky mass were less frequently observed. This study indicates that 3q27(+) FL without t(14;18) translocation have peculiar clinico-pathologic features and may correspond to a rare and distinct subtype of lymphoma originating from the germinal center.     

FISH detection of t(14;18) in follicular lymphoma on Papanicolaou-stained archival cytology slides

BACKGROUND: The t(14;18)(q32;q21) translocation is present in about 85% of follicular lymphomas (FL) and can be identified using fluorescence in situ hybridization (FISH). In the diagnostic laboratory setting, the cytologic archival material consists of stained slides, and only rarely is material saved for molecular testing. The authors proposed FISH for FL using Papanicolaou-stained archival cytology material as a practical ancillary technique for diagnosing FL. METHODS: Cases included 35 FL, 6 small lymphocytic lymphomas/chronic lymphocytic leukemias (SLL/CLL), 4 mantle cell lymphomas (MCL), 4 marginal zone lymphomas (MZL), 1 lymphoplasmacytic lymphoma (LPL), and 10 reactive lymphoid tissues (RLT). FISH was performed on Papanicolaou-stained archival cytology slides using probes for immunoglobulin heavy chain (IGH) on chromosome 14 and BCL2 on chromosome 18. RESULTS: In all, 25 of 32 (81%) FL cases exhibited the t(14;18) translocation, whereas 7 of 32 (19%) lacked the translocation. No cases of non-FL were positive for t(14;18). This series shows a sensitivity of 81% and specificity of 100% for detecting the t(14;18) translocation as a diagnostic tool in FL. CONCLUSIONS: When performed on Papanicolaou-stained cytology slides, FISH for t(14;18) is relatively sensitive and quite specific for FL. These findings are similar to those reported on other specimens, such as paraffin-embedded tissue and unstained cytology slides. The authors proposed that their technique would allow the pathologist and clinician the flexibility to utilize previously stained fine-needle aspiration slides for FISH evaluation.     

Causes and consequences of BCL2 overexpression in diffuse large B-cell lymphoma.

We investigated the frequency of bcl-2 protein overexpression in 80 diffuse large B-cell lymphoma (DLBCL) patients using both Western blotting and immunohistochemistry (IHC). Fifty-nine percent of the DLBCLs overexpressed bcl-2 protein by Western blot and 52% by IHC. The two methods usually gave concordant results (p=0.005), but 14 (21%) out of the 67 cases that were analyzed by both methods were positive by Western blot and negative by IHC, and 8 (12%) cases vice versa. Bcl-2 overexpression by IHC was associated with poor response to chemotherapy and poor survival, whereas these associations were not found when bcl-2 overexpression was determined by Western blotting. The molecular mechanisms leading to bcl-2 overexpression were evaluated by PCR, karyotype analysis, and comparative genomic hybridization (CGH). When studied by PCR and/or karyotype analysis, 12 (15%) of the 80 cases had translocation (14;18)(q32;q21). All 12 lymphomas with (14;18)(q32;q21) translocation had bcl-2 overexpression by Western blot as compared with 35 (51%) of the 68 lymphomas without translocation (p=0.001). Ten (29%) out of 34 cases that were analyzed by CGH showed amplification of chromosome 18 in which the BCL2 gene is located, and all cases showed bcl-2 overexpression by both Western blot and IHC. The results suggest that gene amplification and translocation are at least equally common mechanisms causing bcl-2 protein overexpression in DLBCL. Bcl-2 protein overexpression as determined by IHC is associated with poor response to chemotherapy and poor survival.     

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.     

Abnormalities on 1q and 7q are associated with poor outcome in sporadic Burkitt's lymphoma. A cytogenetic and comparative genomic hybridization study.

Comparative genomic hybridization (CGH) studies have demonstrated a high incidence of chromosomal imbalances in non-Hodgkin's lymphoma. However, the information on the genomic imbalances in Burkitt's Lymphoma (BL) is scanty. Conventional cytogenetics was performed in 34 cases, and long-distance PCR for t(8;14) was performed in 18 cases. A total of 170 changes were present with a median of four changes per case (range 1-22). Gains of chromosomal material (143) were more frequent than amplifications (5) or losses (22). The most frequent aberrations were gains on chromosomes 12q (26%), Xq (22%), 22q (20%), 20q (17%) and 9q (15%). Losses predominantly involved chromosomes 13q (17%) and 4q (9%). High-level amplifications were present in the regions 1q23-31 (three cases), 6p12-p25 and 8p22-p23. Upon comparing BL vs Burkitt's cell leukemia (BCL), the latter had more changes (mean 4.3 +/- 2.2) than BL (mean 2.7 +/- 3.2). In addition, BCL cases showed more frequently gains on 8q, 9q, 14q, 20q, and 20q, 9q, 8q and 14q, as well as losses on 13q and 4q. Concerning outcome, the presence of abnormalities on 1q (ascertained either by cytogenetics or by CGH), and imbalances on 7q (P=0.01) were associated with a short survival.     

Risk factors for non-Hodgkin lymphoma subtypes defined by histology and t(14;18) in a population-based case-control study

The t(14;18) chromosomal translocation is the most common cytogenetic abnormality in non-Hodgkin lymphoma (NHL), occurring in 70-90% of follicular lymphomas (FL) and 30-50% of diffuse large B-cell lymphomas (DLBCL). Previous t(14;18)-NHL studies have not evaluated risk factors for NHL defined by both t(14;18) status and histology. In this population-based case-control study, t(14;18) status was determined in DLBCL cases using fluorescence in situ hybridization on paraffin-embedded tumor sections. Polytomous logistic regression was used to evaluate the association between a wide variety of exposures and t(14;18)-positive (N=109) and -negative DLBCL (N=125) and FL (N=318), adjusting for sex, age, race, and study center. Taller height, more lifetime surgeries, and PCB180 exposure were associated with t(14;18)-positivity. Taller individuals (third tertile vs. first tertile) had elevated risks of t(14;18)-positive DLBCL (odds ratio [OR] = 1.8, 95% confidence interval [CI] 1.1-3.0) and FL (OR=1.4, 95%CI 1.0-1.9) but not t(14;18)-negative DLBCL. Similar patterns were seen for individuals with more lifetime surgeries (13+ vs. 0-12 surgeries; t(14;18)-positive DLBCL OR=1.4, 95%CI 0.7-2.7; FL OR=1.6, 95%CI 1.1-2.5) and individuals exposed to PCB180 greater than 20.8 ng/g (t(14;18)-positive DLBCL OR=1.3, 95%CI 0.6-2.9; FL OR=1.7, 95%CI 1.0-2.8). In contrast, termite treatment and high alpha-chlordane levels were associated with t(14;18)-negative DLBCL only, suggesting that these exposures do not act through t(14;18). Our findings suggest that putative associations between NHL and height, surgeries, and PCB180 may be t(14;18)-mediated and provide support for case-subtyping based on molecular and histologic subtypes. Future efforts should focus on pooling data to confirm and extend previous research on risk factors for t(14;18)-NHL subtypes.     

Screening of genomic imbalances in glioblastoma multiforme using high-resolution comparative genomic hybridization

Comparative genomic hybridization (CGH) is a molecular cytogenetic technique that allows the genome-wide analysis of DNA sequence copy number differences. We applied conventional CGH and the recently developed high-resolution CGH (HR-CGH) to tumour samples from 18 patients with glioblastoma multiforme (GBM) in order to compare the sensitivity of CGH and HR-CGH in the screening of chromosomal abnormalities. The abnormalities were studied in topologically different central and peripheral tumour parts. A total of 78 different changes were observed using CGH (0-16 per tumour, median 3.5) and 154 using HR-CGH (0-21 per tumour, median 6). Using HR-CGH, losses were more frequent than gains. The representation of the most prominent changes revealed by both methods was similar and was comprised of the amplification of 7q12 and 12q13-q15, the gain of 7, 3q and 19, and the loss of 10, 9p, and 13q. However, HR-CGH detected certain other abnormalities (the loss of 6, 14q, 15q and 18q, and the gain of 19), which were rarely revealed by CGH. Using HR-CGH, the numbers and types of chromosomal changes detected in the central and peripheral parts of GBM were almost the same. The loss of chromosomes 10 and 9p and the gain of chromosomes 7 and 19 were the most frequent chromosomal alterations in both tumour parts. Our results from the GBM analysis show that HR-CGH technology can reveal new, recurrent genetic alterations involving the genes known to participate in tumorigenesis and in the progression of several human malignancies, thus allowing for a more accurate genetic characterization of these tumours.     

采用对比基因杂交技术建立嗅神经母细胞瘤基因畸变模型

目的建立嗅神经母细胞瘤(ENB)的基因畸变模型并分析其特征。方法采用对比基因杂交(CGH)技术对12例原发、3例复发、7例转移ENB标本进行基因检测,用特殊软件系统对所采集照片的荧光信号进行量化分析,确定肿瘤DNA与正常对照DNA之间的基因差别。结果ENB常见DNA丢失主要见于1P、2q、3p／q、4p／q、5p／q、6q、8p／q、9p、10p／q、11P、12q、13q、18q和21q,DNA过度表达见于1p、7q、9q、1lq、14q、16p／q、17p／q、19p／q、20p／q和22p／q。ENB的1p21-p31DNA丢失与该类肿瘤患者预后差有明显相关性。死于ENB的患者均具有以下共性：1p21-p31DNA丢失、临床分期为C或D期、分化程度低(Ⅲ或Ⅳ级)。对4例发生转移、复发的患者,将检测结果与其原发病灶基因畸变情况进行对比分析表明,转移、复发病灶与其原发病灶间具有高度的克隆一致性。结论采用CGH能建立ENB的典型基因畸变模型,该模型有助于解释此肿瘤的生物学特性并对其预后进行评估,并与神经母细胞瘤、小细胞肺癌以及头颈部鳞癌进行鉴别。     

Analysis of genomic copy number alterations of malignant lymphomas and its application for diagnosis

Array-based comparative genomic hybridization (array CGH) enables us to detect the genomic copy number alterations of cancers with high resolution. Our established array CGH platform consists of 2,304 BAC/PAC clones covering the whole genome at 1.3-mega base resolutions. Using this technique, we were thus able to reveal disease-specific genomic alterations and the candidate target genes in various lymphomas. We herein report the characteristic genomic alterations of malignant lymphomas including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and adult T cell lymphoma/leukemia (ATLL). The combined use of the array CGH data with gene expression profiling and specific gene rearrangement analyses further delineated the subtype-specific genomic alterations. For instance, we revealed that activated B-cell-like DLBCL is characterized by a gain of chromosome 3, 18q and loss of 9 p21, whereas the germinal center B-cell-like DLBCL is characterized by a gain of 2p15, 7q, and 12q. Among these genomic alterations,we found the 9 p21 loss (p16INK4a locus) to be the most aggressive type of DLBCL. Comparisons of the genome profiles of FL,both with and without BCL2 rearrangement, also revealed the existence of a unique subgroup: trisomy 3 FL. Comparison of genome profiles between acute type and lymphoma types of adult T cell lymphoma also demonstrated that acute and lymphoma types are genomically distinct subtypes, and thus may develop tumors via distinct genetic pathways. In addition to identifying disease-specific genomic alterations, we also discovered several target genes of the genomic gains and losses. Furthermore,we developed a computer algorithm to classify lymphoma diseases or subtypes on the basis of copy number gains and losses. We applied the algorithm to the classifications of DLBCL and MCL diseases and ABC and GCB subtypes. The method correctly classified the DLBCL and MCL diseases at 89%, and ABC and GCB subtypes at 83%. These results demonstrate that copy number gains and losses detected by array CGH could be used for classifying lymphomas into biologically and clinically distinct diseases or subtypes. The genomic copy number alterations detected by array CGH are therefore considered to have the potential to help diagnose or classify different disease entities and tumor subtypes.     

bcl-2与bcl-6在弥漫性大B细胞淋巴瘤中表达的研究

 目的　从蛋白水平和基因水平研究bcl-2、bcl-6在弥漫性大B细胞淋巴瘤（DLBCL）的表达。方法　应用免疫组织化学EnVision法对73例DLBCL进行CD3、CD10、CD20、bcl-2、bcl-6、MUM-1的标记。应用荧光原位杂交（FISH）技术检测其中57例t（14;18）染色体异位bcl-2基因的异常情况和54例bcl-6基因所在的3q27染色体的断裂和扩增情况。结果　肿瘤细胞表达CD10、bcl-6、MUM-1、bcl-2的阳性率分别为15.1 %、38.4 %、71.2 % 、79.2 %。57例患者中16例（28.1 %）存在t（14;18）。bcl-2蛋白表达与免疫学亚型有相关性（P＝0.035）,t（14;18）与预后有相关性（P＝0.045）,t（14;18）与bcl-2蛋白表达无相关性（P＝0.710）。54例中3q27染色体断裂11例（20.4 %）,扩增14例（25.9 %）。bcl-6阳性表达较阴性者预后好（P＝0.041）。bcl-6与3q27断裂和扩增无相关性（均P＝1.000）。结论　bcl-2、bcl-6蛋白和基因表达是各自独立的事件,它们在DLBCL中的意义不同。bcl-2蛋白是与免疫学亚型相关的预后标志物,bcl-2阳性的GCB型预后较差;t（14;18）是独立预后事件,阳性者预后较差,对靶向治疗患者应检测t（14;18）;bcl-6蛋白的表达有助于DLBCL的预后判断,可作为独立的预后因子。3q27染色体断裂可能提示预后较差。     

High incidence of unbalanced chromosomal changes in mantle cell lymphoma detected by comparative genomic hybridization

Comparative genomic hybridization (CGH) was carried out in 30 mantle cell lymphoma (MCL) patients at the time of diagnosis. CGH results were supported by conventional cytogenetics (CC), FISH, molecular genetic PCR methods and 2 patients were examined by array CGH. Using all cytogenetic, molecular cytogenetic and PCR methods, chromosomal changes were detected in 28 (93%) patients. Using CGH, unbalanced chromosomal changes were detected in 24 (80%) cases. The most frequent aberrations were losses of 1p (8 cases), 8p (10 cases), 9q (6 cases), 11q (11 cases), 13q (10 cases) and 17p (9 cases), and gains of chromosome 3 and 3q (12 cases) and 8q (7 cases). Total number of 60 gains and 116 losses were detected. The primary chromosomal change t(11;14) was detected using FISH and/or PCR in 20 (66.6%) patients, and in 9 of them, the breakpoint was determined using PCR in the major translocation cluster (MTC). The evaluation of the frequencies of CGH changes in groups of patients with and without t(11;14) revealed the differences only in losses 6q and 9q, which were only found in patient with t(11;14). An important result was obtained using array CGH method. In a patient without the primary t(11;14), the gain of CCND1 gene was found. Our results show high heterogeneity of the additional chromosomal changes in MCL cases, which involved specific chromosomal subregions. We did not confirm the importance of subdividing of MCL cases with and without t(11;14). Also, statistical significance in survival rates between both subgroups was not confirmed.     

Chromosomal alterations in small cell lung cancer revealed by multicolour fluorescence in situ hybridization

Small cell lung cancer (SCLC) is a major cause of cancer related morbidity and mortality. Karyotypic studies have revealed numerous chromosomal aberrations in most SCLC however, classical G-banding analysis is unable to fully characterise complex marker chromosomes. Recent developments in molecular cytogenetics now allow accurate identification of the chromosomal components of complicated rearrangements. We have applied the technique of multicolour fluorescence in situ hybridization (M-FISH) in combination with comparative genomic hybridization (CGH) to the analysis of 5 SCLC cell lines and 1 primary tumour specimen to characterise the chromosomal abnormalities. CGH analysis identified many similarities between specimens, with frequent DNA copy number decreases on chromosomes 3p, 5q, 10, 16q, 17p and frequent gains on 3q, 1p, 1q and 14q. In contrast, M-FISH analysis revealed a large number of structural abnormalities, with each specimen demonstrating an individual pattern of chromosomal translocations. Forty different translocations were identified with the vast majority (39) being unbalanced. Chromosome 5 was the most frequently rearranged chromosome (9 translocations) followed by chromosomes 2, 10 and 16 (6 translocations each). Further investigation of these frequently involved chromosomes is warranted to establish whether consistent break points are involved in these translocations, causing dysregulation of specific genes that are crucial for tumour progression and secondly to identify the affected genes.     

Discovery of over-expressed genes and genetic alterations in breast cancer cells using a combination of suppression subtractive hybridization,multiplex FISH and comparative genomic hybridization

To identify genes that are involved in breast cancer, suppression subtractive hybridization (SSH) was utilized to construct a breast cancer subtracted library. Differential screening of the library isolated 28 genes which by Northern analysis were highly expressed in the breast cancer cell line MDA-MB-231 compared to the normal breast cell line MCF12A. Sequence analysis revealed that 15 clones coded for previously described genes such as SNAP43, Cyr61, Thymosin beta4, tra1, elongation factor 1alpha, BSF-2/IL6, BiP, and GDP/GTP exchange protein. The remaining 13 clones did not match sequences in GenBank/EMBL database, indicating that they may be novel genes. SNAP43, a subunit of the TBP-TAF complex, was expressed 20-fold higher in MDA-MB-231 compared to MCF12A and several breast cancer cell lines, implying that SNAP43 may be involved in tumorigenesis of a specific subset of breast cancers. Amplification of SNAP43 was not found by Southern analysis. However, genetic alterations of MDA-MB-231 included a deletion of chromosome 14 with a reciprocal translocation t(6;14) and two additional translocations [t(12;14) and t(14;15)] as determined by fluorescent in situ hybridization (FISH) with YAC 823G8 located at chromosome 14q23 which contained SNAP43. Because of the numerous alterations observed by FISH in MDA-MB-231, we further explored the genetic abnormalities in this breast cancer cell line using multiplex FISH (M-FISH) and comparative genomic hybridization (CGH). These cells were replete with numerous complex structural rearrangements and had DNA copy-number imbalances involving multiple chromosomes including gains on chromosomes 2p, 2q31-q32, 3p14-pter, 5q, 6p, 7q36-qter, 11, 14q21-q24, 17p11.2-pter, 17q21-qter, 19, 20, Xp11-q13 and losses on chromosomes 4pter-q32, 8p, 9p21-p24, 10q26-qter, 16p13-pter, 18q12-qter, 22, Xp11.3-p22.1, Xq13-qter. In summary, SSH revealed a number of genes that were either novel or previously not associated with breast cancer. In addition, we found that breast cancer cells abounded with abnormalities as observed by M-FISH and CGH. Together, these results may facilitate defining the genetic alterations associated with breast cancer progression.     

BCL2 mutation spectrum in B‐cell non‐Hodgkin lymphomas and patterns associated with evolution of follicular lymphoma

BCL2 is a target of somatic hypermutation in t(14;18) positive and also in a small fraction of t(14;18) negative diffuse large B‐cell lymphoma (DLBCL), suggesting an aberrant role of somatic hypermutation (ASHM). To elucidate the prevalence of BCL2 mutations in lymphomas other than DLBCL, we Sanger‐sequenced the hypermutable region of the BCL2 gene in a panel of 69 mature B‐cell lymphomas, including Richter's syndrome DLBCL, marginal‐zone lymphomas, post‐transplant lymphoproliferative disorders, HIV‐associated and common‐variable immunodeficiency‐associated DLBCL, all known to harbour ASHM‐dependent mutations in other genes, as well as 16 t(14,18) negative and 21 t(14;18) positive follicular lymphomas (FLs). We also investigated the pattern of BCL2 mutations in longitudinal samples from 10 FL patients relapsing to FL or transforming to DLBCL (tFL). By direct sequencing, we found clonally represented BCL2 mutations in 2/16 (13%) of t(14;18) negative FLs, 2/16 (13%) HIV‐DLBCLs, 1/9 (11%) of Richter's syndrome DLBCL, 1/17 (6%) of post‐transplant lymphoproliferative disorders and 1/2 (50%) common‐variable immunodeficiency‐associated DLBCL. The proportion of mutated cases was significantly lower than in FLs carrying the t(14;18) translocation (15/21, 71%). However, the absence of t(14;18) by FISH or PCR and the molecular features of the mutations strongly suggest that BCL2 represents an additional target of ASHM in these entities. Analysis of the BCL2 mutation pattern in clonally related FL/FL and FL/tFL samples revealed two distinct scenarios of genomic evolution: (i) direct evolution from the antecedent FL clone, with few novel clonal mutations acquired by the tFL major clone, and (ii) evolution from a common mutated long‐lived progenitor cell, which subsequently acquired distinct mutations in the FL and in the relapsed or transformed counterpart. Copyright © 2014 John Wiley & Sons, Ltd.     

Prognostic impact of chromosomal alteration of 3q27 on nodal B-cell lymphoma: correlation with histology, immunophenotype, karyotype, and clinical outcome in 329 consecutive patients

Rearrangements involving the BCL6 gene are found in 30% of diffuse large B-cell lymphomas (DLBCLs). We evaluated the clinical characteristics and prognoses of patients with B-cell lymphoma carrying 3q27 translocations. Among the 59 patients having 3q27 translocation, 10.9% had follicular lymphoma (FL) and 23.1% had DLBCL. It is of interest that the prognostic significance was not found between FL and DLBCL with 3q27 translocations. Progression-free survival (PFS) rate was significantly higher in the FL patients with 3q27 translocation than in those with 18q21 translocation. PFS rate was significantly higher in the DLBCL patients with 3q27 translocation than in those with 18q21 translocation. These findings suggest that the presence of 3q27 translocation is a significant prognostic factor in DLBCL.     

Chromosomal aberrations detected by comparative genomic hybridization (CGH) in human astrocytic tumors

We investigated chromosomal aberrations in 16 patients with astrocytic tumors of various histologic malignancies by comparative genomic hybridization (CGH). The degree of chromosomal loss was shown to be negatively correlated with histologic malignancy. Losses of portions of chromosomes 1p, 19q and 22q were the three chromosomal aberrations observed most frequently. Alterations in multiple chromosomes were observed more frequently in glioblastomas than in astrocytomas or anaplastic astrocytomas (P < 0.001). Primary glioblastomas showed a high frequency of genomic DNA gains (5/7), whereas recurrent glioblastomas from anaplastic astrocytomas did not (0/3). We found CGH to be a powerful tool for surveying DNA alterations in tumors and characterizing the biology of tumors of astrocytic lineage.     

Histological and immunophenotypic changes in 59 cases of B-cell non-Hodgkin's lymphoma after rituximab therapy

Rituximab is a chimeric monoclonal antibody that recognizes the CD20 antigen. It has been used to treat B-cell non-Hodgkin lymphoma (B-NHL), but recently rituximab resistance has been a cause for concern. We examined histological and immunohistochemical changes in 59 patients with B-NHL after rituximab therapy. The patients comprised 32 men and 27 women with a median age of 59 years. Pre-rituximab specimens comprised 34 follicular lymphomas (FL), 11 diffuse large B-cell lymphomas (DLBCL), 10 mantle cell lymphomas, two marginal zone B-cell lymphomas (MZBCL), and two chronic lymphocytic leukemias (CLL). CD20 expression in lymphoma cells was evaluated by immunohistochemistry or flow cytometry. Post-rituximab materials were taken a median of 6 months (4 days to 59 months) after rituximab therapy. Sixteen cases (27%) showed loss of CD20 expression with four histological patterns: pattern 1, no remarkable histological change (FL, 5; DLBCL, 3; and CLL, 2); pattern 2, proliferation of plasmacytoid cells (FL, 2; DLBCL, 1; and MZBCL, 1); pattern 3, transformation to classical Hodgkin's lymphoma (FL, 1); and pattern 4, transformation to anaplastic large cell lymphoma-like undifferentiated lymphoma (FL, 1). Loss of CD20 was unrelated to the interval of biopsies, treatment regimen, clinical response, and frequency of rituximab administration. Loss of CD20 within 1 month of rituximab therapy (3/14, 21%) and regain of CD20 (2/7, 29%) were not frequent. CD20-positive relapse with transformation occurred most frequently in cases of early relapse. In conclusion, B-NHL showed various histological and immunophenotypic changes after rituximab therapy, including not only CD20 loss but also proliferation of plasmacytoid cells or transformation to special subtypes of lymphoma. ( Cancer Sci 2009; 100: 54–61)     

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).