Evidence for local immunosuppression and demonstration of c-myc amplification in pyothorax-associated lymphoma

AIMS: Pyothorax-associated lymphoma (PAL) develops in the pleural cavity of patients with a long history of pyothorax. Epstein-Barr virus (EBV) is also involved in PAL, similar to lymphomas in immunodeficient patients. Here we examined T-lymphocyte subsets as well as c-myc and REL gene amplification in PAL tissues. METHODS AND RESULTS: We determined the number and distribution of CD4+ and CD8+ T-lymphocytes, to evaluate T-cells in the host immune reaction in seven cases of PAL. As controls, we also studied 10 cases of extranodal diffuse large B-cell lymphoma (DLBL) and 10 cases of nodal DLBL. Chromosomal imbalances in PAL were determined by using comparative genomic hybridization (CGH) analysis. The mean numbers of CD4+ and CD8+ and their ratio were significantly lower in PAL than in nodal DLBL. CGH analysis of PAL showed amplification of the 8q24 chromosomal region. In addition, c-myc amplification was found in four cases of PAL by Southern blot analysis. CONCLUSIONS: Our results suggest that the development of PAL may involve a local immunosuppressive environment and that amplification of c-myc might promote tumour progression, as has been described in the development of Burkitt's lymphoma.     

Chromosomal aberrations in angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma unspecified: A matrix-based CGH approach

Angioimmunoblastic T-cell lymphoma (AILT) is a histopathologically well-defined entity. However, despite a number of cytogenetic studies, the genetic basis of this lymphoma entity is not clear. Moreover, there is an overlap to some cases of peripheral T-cell lymphoma unspecified (PTCL-u) in respect to morphological and genetic features. We used array-based comparative genomic hybridization (CGH) to study genetic imbalances in 39 AILT and 20 PTCL-u. Array-based CGH revealed complex genetic imbalances in both AILT and PTCL-u. Chromosomal imbalances were more frequent in PTCL-u than in AILT and gains exceeded the losses. The most recurrent changes in AILT were gains of 22q, 19, and 11p11-q14 (11q13) and losses of 13q. The most frequent changes in PTCL-u were gains of 17 (17q11-q25), 8 (involving the MYC locus at 8q24), and 22q and losses of 13q and 9 (9p21-q33). Interestingly, gains of 4q (4q28-q31 and 4q34-qtel), 8q24, and 17 were significantly more frequent in PTCL-u than in AILT. The regions 6q (6q16-q22) and 11p11 were predominantly lost in PTCL-u. Moreover, we could identify a recurrent gain of 11q13 in both AILT and PTCL-u, which has previously not been described in AILT. Trisomies 3 and 5, which have been described as typical aberrations in AILT, were identified only in a small number of cases. In conclusion, CGH revealed common genetic events in peripheral T-cell lymphomas as well as peculiar differences between AILT and PTCL-u.     

CELLULAR KINETIC AND PHENOTYPIC HETEROGENEITY IN AND AMONG BURKITT'S AND BURKITT-LIKE LYMPHOMAS

This study asks whether the known genotypic heterogeneity within and between endemic or sporadic Burkitt's lymphomas (eBLs and sBLs, n=10 each), and Burkitt-like lymphomas (BLLs, n-12), is reflected in divergent cytokinetics and related immunophenotypes. There was strong evidence that eBL and BLL grow markedly faster than sBL, as shown by differences in mitotic and apoptotic indices. Furthermore, in BLL, the median percentage of neoplastic cells immunoreactive for the bcl-2 protein was much higher than that observed in eBL and sBL. The reverse was true for the median fraction of cells containing c-myc protein. In eBL and sBL, the median fraction of bcl-6 protein-positive cells reached values above 50 per cent, while cells of 8/12 BLLs did not contain detectable amounts of this protein. This observation indicates that in this respect, eBL and sBL resemble normal germinal centres of lymphatic tissue much more than do BLL. Evidence for infection of neoplastic cells by the Epstein-Barr virus (EBV) was observed in 9/10 cases of eBL and in 3/10 of sBL, but not in BLL. EBV-positive lymphomas were associated with distinctly lower apoptotic indices and smaller median percentages of bcl-6-positive cells than EBV-negative tumours. © 1997 John Wiley & Sons, Ltd.     

Molecular-cytogenetic comparison of mucosa-associated marginal zone B-cell lymphoma and large B-cell lymphoma arising in the gastro-intestinal tract.

Extranodal B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type may represent a model of lymphoma progression, because a small cell component frequently occurs in the large cell variants. We studied 52 extranodal B-cell lymphomas: 18 extranodal marginal zone B-cell lymphomas of MALT type (MZBL,MT), 7 MZBL,MT of the gastro-intestinal tract with a diffuse large B-cell component (giMZBLplusLBCL), and 27 diffuse large B-cell lymphomas of the gastro-intestinal tract without small cell component (giLBCL). Analytical techniques were comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). The translocation t(11;18) was found as the sole aberration in two MZBL,MT only. In contrast to this, t(11;18)-negative MZBL,MT were characterized by frequent gains on chromosome 3 and DNA amplifications on 2p13-p15. Furthermore, we found a clonal lymphoma progression from the small to the large cell component with accumulation of gains and losses of chromosomal material in the large cell component in giMZBLplusLBCL. Aberrations overlapping with MZBL,MT and giMZBLplusLBCL included losses on chromosome 13, amplifications of the REL proto-oncogene, or gains on chromosome 12. In addition, the large cell component revealed gains on 8q24, including amplifications of the MYC proto-oncogene, and losses on 2q. The giLBCL had frequent gains on chromosomes 12 and 9, as well as on 11q, and losses on 6q. We conclude that, based on the distinctive and partly overlapping patterns of genetic aberrations, MALT lymphomas can be divided into different genetic subgroups.     

Recurrent genomic imbalances in B-cell splenic marginal-zone lymphoma revealed by comparative genomic hybridization

The cytogenetics of splenic marginal zone lymphoma (SMZL) is less well characterized than the cytogenetics of other non-Hodgkin B-cell lymphomas. The aim of this study was to address this issue by identifying characteristic copy number imbalances in SMZL, for which purpose we analyzed 20 SMZL cases by comparative genomic hybridization (CGH), adding chromosome banding and fluorescence in situ hybridization (FISH) in some cases. CGH identified copy number imbalances in 70% of the cases. Imbalances were recurrently observed for chromosomes 3 (20%), 6 (20%), 7 (25%), 12 (20%), and 14 (10%). The minimally involved regions of these chromosomes were gains of 3q25 approximately qter and 12q13 approximately q15, and loss of 6q23, 7q31, and 14q22 approximately q24. A compilation of our data with data from 3 previous SMZL CGH studies revealed a significant heterogeneity between the studies. Eleven imbalances were recurrently observed in the compiled data set, as opposed to only 5 in our data set. The most frequently observed imbalances in the 73 SMZL cases of the compiled data set were gains of 3q (27%) and 12q (15%), and loss of 7q (18%). Our data suggest that SMZL constitute a genetically heterogeneous disease where gain of 3q25 and loss of 7q31 are the most likely imbalances to be involved in the pathogenesis of the disease.     

Genetic alterations in primary cutaneous CD30+ anaplastic large cell lymphoma

Primary cutaneous CD30+ anaplastic large cell lymphoma (C-ALCL) represents a distinct clinical subtype of CD30+ anaplastic large cell lymphomas. The etiology and underlying molecular pathogenesis of C-ALCL remain unclear. This study aimed to investigate genetic changes in C-ALCL. Comparative genomic hybridization (CGH) analysis of 23 DNA samples from 15 C-ALCL cases identified chromosome imbalances (CI) in 10 samples from eight cases (43%). The mean number of CI per sample was 2.09 +/- 3.86, with gains (2.00 +/- 3.85) more common than losses (0.09 +/- 0.29). The most frequent CI were gains of 1/1p and 5 (50%) and 6, 7, 8/8p, and 19 (38%). Microarray-based CGH analysis of six DNA samples from five cases with CI revealed genomic imbalances (GI) in all of the cases studied. This included oncogene copy number gains of FGFR1 (8p11) in three cases, and NRAS (1p13.2), MYCN (2p24.1), RAF1 (3p25), CTSB (8p22), FES (15q26.1), and CBFA2 (21q22.3) in two cases. Real-time PCR analysis of nine DNA samples from eight cases with CI and GI detected amplifications of CTSB and RAF1 in seven cases (88%), REL (2p13p12) and JUNB (19p13.2) in six cases (75%), and MYCN and YES1 (18p11.3) in four cases (50%). Immunohistochemical staining of paraffin sections from six cases demonstrated expression of JUNB protein in five cases and BCL2 in three cases. These results reveal a consistent pattern of genetic alterations in C-ALCL and provide the molecular basis for further investigation of this disease.     

Analysis of chromosomal copy number changes and oncoprotein expression in primary central nervous system lymphomas: frequent loss of chromosome arm 6q

Primary central nervous system lymphoma (PCNSL) is a rare disease. A small number of cytogenetic studies of PCNSL have been conducted and several reports have been published on associated molecular and protein expression data. We combined these approaches in a series of eight PCNSL cases, analyzing the chromosomal abnormalities using comparative genomic hybridization (CGH), testing for Epstein Barr virus (EBV) involvement by in situ hybridization for EBER, assessing expression of p53, Bcl-2, Bcl-6 and CD10 by means of immunohistochemistry, and screening for mutations of the TP53 gene by DGGE. TP53 gene mutations and EBV expression were not detected. Most of the cases showed p53, Bcl-6 and Bcl-2 protein expression. CGH revealed DNA copy number changes in all eight cases. The most frequent changes were gains of chromosome 12 (63%), chromosome 18 (50%) and 20q (38%), and loss of chromosome arm 6q (75%). No correlation between protein expression and chromosomal abnormalities was found in these eight cases. Although gains of chromosome 12, 18 and 20q and loss of 6q have also been reported in systemic diffuse large B-cell lymphomas, the frequency of 6q deletion is clearly higher in PCNSL. This creates a similarity to primary lymphomas of the testes that also frequently have deletions of 6q. This suggests that suppressor genes located on chromosome 6q may play a role in the development of lymphomas at immunoprivileged sites, like the CNS.     

Novel genomic imbalances in B-cell splenic marginal zone lymphomas revealed by comparative genomic hybridization and cytogenetics

Splenic marginal zone lymphoma (SMZL) has recently been recognized in the World Health Organization classification of hematological diseases as distinct type of non-Hodgkin's lymphoma. In contrast to the well-established chromosomal changes associated with other B-cell non-Hodgkin's lymphoma, few genetic alterations have been found associated with SMZL. The aim of our study was to analyze by comparative genomic hybridization (CGH) the chromosomal imbalances in 29 patients with SMZL and to correlate these findings with clinical and biological characteristics and patient outcome. In 21 cases, cytogenetic studies were simultaneously performed. Most of the patients (83%) displayed genomic imbalances. A total of 111 DNA copy number changes were detected with a median of four abnormalities per case (range, 1 to 12). Gains (n = 92) were more frequent than losses (n = 16), while three high-level amplifications (3q26-q29, 5p11-p15, and 17q22-q25) were observed. The most frequent gains involved 3q (31%), 5q (28%), 12q and 20q (24% each), 9q (21%), and 4q (17%). Losses were observed in 7q (14%) and 17p (10%). SMZL patients with genetic losses had a shorter survival than the remaining SMZL patients (P < 0.05). In summary, chromosomal imbalances in regions 3q, 4q, 5q, 7q, 9q, 12q, and 20q have been detected by CGH in SMZL. Patients with SMZL displaying genetic losses by CGH had a short survival.     

Nonrandom chromosomal imbalances in primary mediastinal B-cell lymphoma detected by arbitrarily primed PCR fingerprinting.

We used arbitrarily primed polymerase chain reaction (AP-PCR) fingerprinting to identify chromosomal imbalances in six primary mediastinal B-cell lymphomas (PMBLs). Seventy-four chromosomal imbalances were detected, consisting of 49 sequence gains and 25 losses. Amplifications on chromosome X were seen in five cases, four of which involved the same chromosomal locus. Nonrandom gains at the same locus were also identified on chromosomes 2 and 7 in four cases and on chromosomes 5, 9, and 12 in three cases. Five PMBLs were also analyzed by comparative genomic hybridization (CGH), which found chromosome arm 9p amplification as the only nonrandom imbalance. Our data demonstrate that chromosomal amplifications outnumber losses in PMBL. These mainly involve chromosomes 9 and X and may reflect more complex phenomena, such as translocations or other chromosomal rearrangements, as AP-PCR found coexistent gains and losses on these chromosomes. Comparison between AP-PCR and CGH suggests that anomalies affecting the same chromosomal regions may occur at much higher frequencies than expected by CGH, suggesting that genomic amplifications are usually confined to DNA segments smaller than the megabase long segments required for detection in CGH. Modest increases in genetic material may be as effective as higher-level amplifications when affecting sites where a proto-oncogene resides.     

t(11;14)-positive mantle cell lymphomas exhibit complex karyotypes and share similarities with B-cell chronic lymphocytic leukemia

Until now, few data on additional chromosomal aberrations in t(11;14)-positive mantle cell lymphomas (MCLs) have been published. We analyzed 39 t(11;14)-positive MCLs by either comparative genomic hybridization (CGH; n = 8), fluorescence in situ hybridization (FISH) with a set of DNA probes detecting the most frequent aberrations in B-cell neoplasms (n = 12), or both techniques (n = 19). The t(11;14) was present in all cases. In 37 of 39 cases, chromosomal imbalances were found. In 27 cases, complex karyotypes, i.e., >/= 3 aberrations, were identified. The most frequent aberrations were losses of 13q14-21 or 13q32-34 (27 cases), 9p21 (16 cases), and 11q22-23 (12 cases) and gains of 3q26-29 (19 cases), 8q22-24 (11 cases), and 18q21-22 (9 cases). In 26% of cases (7 of 27) analyzed by CGH, a total of 10 high-level DNA amplifications were identified. Although in comparison with B-cell chronic lymphopcytic leukemia (B-CLL) MCL is characterized by a much higher complexity of chromosomal aberrations, there are striking similarities: 13q14 deletions were identified in more than 50% of both MCL and B-CLL cases. In contrast, in our CGH database containing 293 B-cell lymphomas, this aberration was found in only 11% of other nodal lymphomas. Even more strikingly, 11q deletions, which are present in 20%-30 % of MCL and B-CLL, were found very rarely in other nodal B-cell lymphomas (CGH: 1 of 208 cases; FISH: 1 of 69 cases). These data show that MCL is characterized by specific secondary aberrations and that there may be similarities in the pathogenesis of MCL and B-CLL. Genes Chromosomes Cancer 27:285-294, 2000.     

Chromosomal gains at 9q characterize enteropathy-type T-cell lymphoma

Genetic alterations in enteropathy-type T-cell lymphoma (ETL) are unknown so far. In this series, 38 cases of ETL were analyzed by comparative genomic hybridization (CGH). CGH revealed chromosomal imbalances in 87% of cases analyzed, with recurrent gains of genetic material involving chromosomes 9q (in 58% of cases), 7q (24%), 5q (18%), and 1q (16%). Recurrent losses of genetic material occurred on chromosomes 8p and 13q (24% each), and 9p (18%). In this first systematic genetic study on ETL, chromosomal gains on 9q (minimal overlapping region 9q33-q34) were found to be highly characteristic of ETL. Fluorescence in situ hybridization analysis on four cases of ETL, using a probe for 9q34, indicated frequent and multiple gains of chromosomal material at 9q34 (up to nine signals per case). Among 16 patients with ETL who survived initial disease presentation, patients with more than three chromosomal gains or losses (n = 11) followed a worse clinical course than those with three or less imbalances (n = 5). The observation of similar genetic alterations in ETL and in primary gastric (n = 4) and colonic (n = 1) T-cell lymphoma, not otherwise specified, is suggestive of a genetic relationship of gastrointestinal T-cell lymphomas at either localization.     

Cytogenetic characterization of three cases of unusual B-cell non-Hodgkin's lymphoma

We report the cytogenetic results in three cases of B-cell non-Hodgkin's lymphomas with morphologic and immunophenotypic features compatible with a non-follicle center cell lymphoma. In all cases, a chromosome breakpoint at 14q32 and structural abnormalities of 1p were found. Increased copies of chromosome segment 12q and structural rearrangements of chromosome 6 were found in two cases. Translocation (14;18)(q32;q21) with rearrangement of bcl-2 was found in one case. These lymphomas have a perifollicular growth pattern and IgM+, IgD+, CD10-, and CD22+ immunophenotype features typical of non-follicle center cell lymphomas and probably belong to the follicle mantle lymphomas described recently. Little cytogenetic data about this group of lymphomas is available, possibly because in the Working Formulation for the Classification of Lymphomas they are not separated from follicle center cell lymphomas.     

Comparative genomic hybridization analysis of natural killer cell lymphoma/leukemia. Recognition of consistent patterns of genetic alterations.

Putative natural killer (NK) cell lymphoma/leukemia is a rare group of recently characterized hematolymphoid malignancies. They are highly aggressive and frequently present in extranodal sites, including the nasal area and the upper aerodigestive system, and nonnasal areas such as the skin and the gastrointestinal tract. According to clinicopathological features, they can be classified into nasal NK cell lymphoma, nasal-type NK cell lymphoma occurring in nonnasal areas, and NK cell lymphoma/leukemia. Genetic alterations in NK cell lymphoma/leukemia are not well defined. In this study, we have performed comparative genomic hybridization (CGH) on DNA extracted from fresh or frozen tissues of 10 patients with NK cell lymphoma/leukemia. They comprised four nasal NK cell lymphomas, one nasal-type NK cell lymphoma, and five NK cell lymphomas/leukemias. CGH showed frequent deletions at 6q16-q27 (four cases), 13q14-q34 (three cases), 11q22-q25 (two cases), 17p13 (two cases), and loss of the whole chromosome X (two cases). DNA amplification was observed in a majority of the chromosomes. Five cases showed DNA gains at region 1p32-pter. Frequent DNA gains were also found in chromosomes 6p, 11q, 12q, 17q, 19p, 20q, and Xp (three cases each). Interestingly, DNA gains were more frequent in nasal/nasal-type NK cell lymphomas than NK cell lymphoma/leukemia. These genetic alterations correlated well with karyotypic features found in some of the cases. The frequent DNA losses at 6q and 13q suggest that the presence of tumor suppressor genes at these regions is important in NK cell transformation. In addition to establishing novel patterns of genomic imbalances in these rare NK cell malignancies, which may be targets for future molecular analysis, this study also provides important information on genetic alterations in NK cell lymphomas that may be useful in defining their positions in current lymphoma classification schemes, which are increasingly focusing on phenotypic and genotypic correlations.     

Comparative genomic hybridization pattern distinguishes T-cell/histiocyte-rich B-cell lymphoma from nodular lymphocyte predominance Hodgkin's lymphoma

Several lines of evidences suggest that T cell/histiocyte-rich B-cell lymphoma (T/HRBCL) represents an aggressive variant of the clinically indolent entity nodular lymphocyte predominance Hodgkin's lymphoma (LPHL). Still, this view has not yet been supported by firm genetic evidence. In this study, we analyzed 17 T/HRBCL cases using comparative genomic hybridization (CGH) combined with microdissection of single CD20+ neoplastic cells and DNA amplification by degenerate oligonucleotide primed-polymerase chain reaction, an approach we previously used in LPHL. Genomic imbalances were detected in all cases (in total, 80 changes). The most common imbalances included gain of Xq, 4q13q28, Xp21p11, and 18q21, and loss of 17p. Of note, a partial gain of 4q, a rare change in lymphoma, is also among the genomic imbalances most frequently encountered in LPHL. On the other hand, the CGH profiles of T/HRBCL and LPHL showed several distinct features, in particular with respect to the number of genomic imbalances (average of 4.7 in T/HRBCL versus 10.8 in LPHL) and their distribution (usually 1 to 5 in T/HRBCL versus 6 to 22 in LPHL). Altogether, our CGH findings of shared as well as distinctive cytogenetic features in both diseases suggest that T/HRBCL constitutes a separate lymphoma entity, possibly originating from the same precursor cell as LPHL.     

儿童散发性伯基特淋巴瘤的分子遗传学特征分析

目的 研究儿童散发性伯基特淋巴瘤(BL)的分子遗传学特征及其诊断和鉴别诊断.方法 对64例儿童BL和6例儿童弥漫性大B细胞淋巴瘤(DLBCL)进行免疫组织化学染色(SP法)和荧光原位杂交(FISH)技术检测c-myc、bcl-2、bcl-6、IgH、myc/lgH及bcl-2/IgH基因重排的情况.根据细胞起源分类分为生发中心组(GC组)、生发中心晚期组(late-GC组)、生发中心后组(post-GC组).结果 BL表达CD20(64例)、CD10(63例)、bcl-6(62例)、MUM1(15例)、bcl-2(0例).GC组49例(76.6%)、late-GC组14例(21.9%)、post-GC组1例(1.6%).c-myc基因断裂54例(93.1%);IgH基因断裂48例(82.8%);c-myc与IgH基因同时断裂并myc/IgH基因易位46例(85.2%);c-myc基因断裂、IgH和myc/IgH基因正常4例(7.4%);c-myc、IgH和myc/IgH基因均正常4例(7.4%);bcl-2基因正常61例(100%);bcl-6基因正常59例,1例断裂并扩增具有BL的病理形态和免疫表型特征,同时具有c-myc基因断裂,将病理诊断修改为介于DLBCL和BL之间的未分类的B细胞淋巴瘤(DLBCL/BL).6例DLBCL中c-myc基因断裂2例;2例bcl-6基因扩增,其中1例伴c-myc基因断裂;无bcl-2/IgH基因重排.结论 儿童散发性BL大多数来源于生发中心B细胞,c-myc基因的断裂是其主要分子遗传学改变.应用FISH进行多基因的检测,有助于提高儿童BL的诊断和鉴别诊断水平.     

Expression of transmembrane adaptor protein PAG/Cbp in diffuse large B-cell lymphoma: immunohistochemical study of 73 cases

PAG/Cbp is a transmembrane adaptor protein involved in proximal immune signaling. It is expressed in reactive germinal centers (GC) of secondary lymphatic follicles and related malignant lymphomas. We studied PAG/Cbp expression in GC-like and non-GC-like diffuse large B-cell lymphoma (DLBCL) subtypes. Seventy-three cases of DLBCL identified among 155 malignant lymphomas were classified as GC-like DLBCL (CD10+ or CD10-, bcl-6+, and MUM1-) and non-GC-like DLBCL (CD10-, MUM1+ or CD10-, bcl-6+, MUM1+). PAG/Cbp was detected by monoclonal antibody MEM-255 following routine immunohistochemical procedures. Thirty-five of 40 GC-like DLBCLs (88%) and 20 of 33 non-GC-like DLBCL cases (61%) expressed PAG/Cbp. Four of 12 bcl-6-negative non-GC-like DLBCL cases (33%) were PAG/Cbp positive, and only 4 of 20 bcl-6-positive non-GC-like DLBCL cases (25%) were PAG/CBP negative. All 37 FL and all 5 Burkitt's lymphomas (BL) expressed PAG/Cbp, whereas all 6 mantle cell lymphomas (MCL) and 4 of 5 chronic lymphocytic leukemias (CLL/SLL) were PAG/Cbp negative. PAG/Cbp is a reliable GC marker. Its expression correlates with GC-like DLBC phenotype in a significant majority of cases. It is typically absent in MCL and SLL/CLL.     

Distinct primary central nervous system lymphoma defined by comparative genomic hybridization and laser scanning cytometry

We investigated chromosomal alterations using comparative genomic hybridization (CGH), and DNA ploidy patterns using laser scanning cytometry (LSC) in 8 primary central nervous system lymphomas (PCNSLs). The average number of chromosomal alterations detected by CGH was 6.9 (gain: 4.1, deletion: 2.8). Frequent alterations were gains of chromosomes 12, 18q, and X, and deletion of 6q, which were similar to those seen in non-CNS diffuse large B-cell lymphoma. DNA aneuploidy was detected by LSC in 4 of the 8 cases. The DNA aneuploid lymphomas had more chromosomal alterations than the DNA diploid ones (9.3 vs. 4.5, P <.05). The former had higher MIB-1 indices than the latter. The present investigation indicates that although most of the PCNSL are histologically uniform, they are divided cytogenetically into DNA aneuploid and diploid tumors.     

T细胞淋巴瘤1和CD44蛋白在Burkitt淋巴瘤中的表达及其诊断价值

目的 探讨T细胞淋巴瘤1(TCL1)和CD44蛋白在Burkitt淋巴瘤中的表达及其诊断价值.方法 在石蜡包埋的实验组25例Burkitt淋巴瘤和对照组25例非特指弥漫性大B细胞淋巴瘤(DLBCL)中采用免疫组织化学EnVision法检测CD44、TCLl以及CD10、bel-2、bcl-6、c-myc、Ki-67等常用抗体表达情况.结果 Burkitt淋巴瘤中瘤细胞96%(24例)呈TCL1阳性,仅4%(1例)CD44阳性;88%(22例)CD10阳性、92%(23例)bcl-6和c-myc阳性,仅4%(1例)bcl-2阳性;Ki-67增殖指数为95%～100%.非特指DLBCL中仅16%(4例)TCL1弱阳性,84%(21例)CD44阳性、32%(8例)CD10阳性、72%(18例)bcl-6和bcl-2阳性、c-myc均阴性,Ki-67增殖指数40%～90%.结论 当形态和免疫表型不典型时,TCL1和CD44两种蛋白的检测有助于提高Burkitt淋巴瘤的确诊率及其与DLBCL的鉴别诊断.     

Burkitt- und Burkitt-ähnliche Lymphome

Among aggressive mature B-cell lymphomas, a reproducible morphological and immunohistological distinction between Burkitt's lymphoma and diffuse large B-cell lymphoma (centroblastic variant) is impossible in a substantial number of cases. The German reference centres for hematopathology collected 220 retrospective cases of aggressive mature B-cell lymphoma whose classification according to the current World Health Organisation criteria was reviewed. Gene expression analysis (Affymetrix) was performed in all cases and chromosomal translocations were determined using fluorescence in situ hybridization. Chromosomal losses and gains were analysed by matrix comparative genomic hybridisation and clinical data were successfully collected for most patients. The application of a novel bioinformatics method led to the identification of a stable and reproducible gene expression signature specific for Burkitt's lymphoma. A total of 44 cases were identified by this molecular signature [designated molecular Burkitt's lymphoma (mBL)]. These molecular Burkitt's lymphomas showed the morphology and immunohistology of classical or atypical Burkitt's lymphoma cases in 29 instances. However, 15 of the molecular Burkitt's lymphoma cases had the morphology of diffuse large B-cell lymphoma or could not be further specified. All molecular Burkitt's lymphomas showed an expression of BCL-6 and CD10, but a MYC translocation was not demonstrable in more than 10% of cases. Of significance is that more than 20% of the molecular Burkitt's lymphomas expressed BCL-2, although weakly in most instances. Our data demonstrate that: (1) the morphological, immunophenotypical and genetic spectrum of Burkitt's lymphoma is broader than previously expected, and (2) our molecular Burkitt's lymphoma signature enables a more precise and extended definition this lymphoma.     

High-resolution mapping of amplifications and deletions in pediatric osteosarcoma by use of CGH analysis of cDNA microarrays

Conventional cytogenetic and comparative genomic hybridization (CGH) studies have shown that osteosarcomas (OSs) are characterized by complex structural and numerical chromosomal alterations and gene amplification. In this study, we used high-resolution CGH to investigate recurrent patterns of genomic imbalance by use of DNA derived from nine OS tumors hybridized to a 19,200-clone cDNA microarray. In six OSs, there was copy number gain or amplification of 6p, with a minimal region of gain centering on segment 6p12.1. In seven OSs, the pattern of amplification affecting chromosome arm 8q showed high-level gains of 8q12-21.3 and 8q22-q23, with amplification of the MYC oncogene at 8q24.2. Seven OSs showed copy number gain or amplification of 17p between the loci bounded by GAS7 and PMI (17p11.2-17p12), and three of these tumors also showed small losses at 17p13, including the region containing TP53. An in silico analysis of the distribution of segmental duplications (duplicons) in this region identified a large number of tracts consisting of paralogous sequences mapping to the 17p region, encompassing the region of deletions and amplifications in OS. Interestingly, within this same region there were clusters of duplicons and several genes that are expressed during bone morphogenesis and in OS. In summary, microarray CGH analysis of the chromosomal imbalances of OS confirm the overall pattern observed by use of metaphase CGH and provides a more precise refinement of the boundaries of genomic gains and losses that characterize this tumor.