The PTPN22gain-of-function+1858T(+) genotypes correlate with low IL-2 expression in thymomas and predispose to myasthenia gravis

Protein tyrosine phosphatase, non-receptor type 22 (PTPN22) inhibits T-cell activation and interleukin-2 (IL-2) production. The PTPN22(gain-of-function)+1858T(+) genotypes predispose to multiple autoimmune diseases, including early-onset (non-thymomatous) myasthenia gravis (MG). The disease association and the requirement of IL-2/IL-2 receptor signaling for intrathymic, negative T-cell selection have suggested that these genotypes may weaken T-cell receptor (TCR) signaling and impair the deletion of autoreactive T cells. Evidence for this hypothesis is missing. Thymoma-associated MG, which depends on intratumorous generation and export of mature autoreactive CD4(+) T cells, is a model of autoimmunity because of central tolerance failure. Here, we analyzed the PTPN22 +1858C/T single nucleotide polymorphism in 426 German Caucasian individuals, including 125 thymoma patients (79 with MG), and investigated intratumorous IL-2 expression levels. Unlike two previous studies on French and Swedish patients, we found strong association of PTPN22 +1858T(+) genotypes not only with early-onset MG (P=0.00034) but also with thymoma-associated MG (P=0.0028). IL-2 expression in thymomas with PTPN22 +1858T(+) genotypes (P=0.028) was lower, implying weaker TCR signaling. We conclude that the PTPN22(gain-of-function) variant biases towards MG in a subgroup of thymoma patients possibly by impeding central tolerance induction.

[Lymphomas of the spleen]

The spleen is commonly affected by malignant lymphomas and the macroscopic findings of the spleen correlate with different lymphoma entities. However, most lymphomas are not primarily diagnosed in splenectomy specimens. Exceptions include splenic marginal zone lymphomas and hepatosplenic T-cell lymphomas that are typically diagnosed from histological findings. In addition, hairy-cell leukemia, LGL leukemia and T-cell prolymphocytic leukemia typically show characteristic patterns of infiltration in the spleen which may be diagnostically useful. The different infiltration patterns of these tumors are discussed here.

[Inflammatory reactions of the spleen]

Inflammatory reactions of the spleen occur in the context of two pathophysiological settings. First, lymphoid hyperplasia of the spleen can be the result of a principally physiological production of immune effector cells e.g. due to systemic viral infections, autoimmune diseases and acquired or inherited immunodeficiencies. Second, the spleen itself may be the target of a pathological inflammatory reaction; this setting is exemplified by abscess formation due to septicopyemic spread of bacteria and by granulomatous inflammations, e.g. due to tuberculosis or sarcoidosis. Differential diagnostic considerations have to include splenic inflammatory pseudotumors, mycobacterial spindle cell tumors and lymphomas with granulomatous or histiocyte-rich reactive changes.

[Splenic marginal zone B cell lymphomas]

Splenic marginal zone B cell lymphomas (SMZBCL) are rare, organotypic, lymphoid neoplasms with distinct clinicopathological features. At initial presentation, the spleen, bone marrow and peripheral blood are usually involved, while generalized lymphadenopathy is only rarely observed. Molecularly, somatic hypermutation of IgVH genes can be detected in roughly half of the cases, and deletions in 7q are present in 45% of tumors. Approximately 10%-15% of SMZBCL do occur in the setting of chronic hepatitis C. This association underlines the importance of antigenic stimulation in the proliferation of the tumor cells in HCV-associated SMBCL, if not also in their classical counterparts. More recently, gene profiling studies using cDNA microarrays revealed a homogeneous expression profile in SMZBCL, thus further confirming the notion of a distinct tumor entity. The clinical course is indolent in the majority of cases; however, some patients follow a more aggressive clinical course, usually associated with some particular molecular features in these tumors, such as unmutated IgVH genes and 7q deletions.

A20 deletion is associated with copy number gain at the TNFA/B/C locus and occurs preferentially in translocation-negative MALT lymphoma of the ocular adnexa and salivary glands

The genetic basis of MALT lymphoma is largely unknown. Characteristic chromosomal translocations are frequently associated with gastric and pulmonary cases, but are rare at other sites. We compared the genetic profiles of 33 ocular adnexal and 25 pulmonary MALT lymphomas by 1 Mb array-comparative genomic hybridization (CGH) and revealed recurrent 6q23 losses and 6p21.2-6p22.1 gains exclusive to ocular cases. High-resolution chromosome 6 tile-path array-CGH identified NF-kappaB inhibitor A20 as the target of 6q23.3 deletion and TNFA/B/C locus as a putative target of 6p21.2-22.1 gain. Interphase fluorescence in situ hybridization showed that A20 deletion occurred in MALT lymphoma of the ocular adnexa (8/42=19%), salivary gland (2/24=8%), thyroid (1/9=11%) and liver (1/2), but not in the lung (26), stomach (45) and skin (13). Homozygous deletion was observed in three cases. A20 deletion and TNFA/B/C gain were significantly associated (p<0.001) and exclusively found in cases without characteristic translocation. In ocular cases, A20 deletion was associated with concurrent involvement of different adnexal tissues or extraocular sites at diagnosis (p=0.007), a higher proportion of relapse (67% versus 37%) and a shorter relapse-free survival (p=0.033). A20 deletion and gain at TNFA/B/C locus may thus play an important role in the development of translocation-negative MALT lymphoma.

[Splenic vascular disturbances]

Splenic vascular disturbances mainly affect the red pulp and can involve the venous or arterial blood flow. The venous blood flow may be impaired by congestion and morphologically shows dilated splenic sinuses. Disturbances of the arterial blood flow may occur in connection with anomalies of the erythrocyte membrane or in immune haemolysis and usually are characterized by narrow splenic sinuses. Infarction of the spleen is usually caused by arterial embolism.

Gastric extranodal marginal zone B-cell lymphomas of MALT type exclusively express Toll-like receptor 4 in contrast to other lymphomas infiltrating the stomach

BACKGROUND

Development and growth of extranodal marginal zone B-cell lymphomas (eMZBCLs) of mucosa-associated lymphoid tissue (MALT) type are thought to be highly dependent on Helicobacter pylori and autoantigens. Receptors mediating these effects are not characterised so far. Toll-like receptors (TLRs) recognise bacterial proteins and autoantigens, which results in inflammatory reactions and influences tumour development and growth.

MATERIALS AND METHODS

TLR4, 5 and 9 expressions were evaluated by immunohistology and confocal microscopy in gastric eMZBCL in comparison to other lymphomas infiltrating the stomach.

RESULTS

TLR4 was exclusively expressed on the cell surface in all eMZBCL (n = 19) and not in chronic lymphocytic leukaemia (CLL, n = 12) or mantle cell lymphoma (MCL, n = 10). TLR5 was strongly expressed in CLL and weak in some eMZBCL (15 of 19), but not in MCL. TLR4, 5 and 9 were negative in all the three lymphoma entities.

CONCLUSIONS

Exclusive TLR4 expression may enable eMZBCL to interact with H. pylori and autoantigens. Blockade of TLR4 might be a new approach for therapy of eMZBCL of MALT type.

Detailed mapping of chromosome 17p deletions reveals HIC1 as a novel tumor suppressor gene candidate telomeric to TP53 in diffuse large B-cell lymphoma

Deletions in the short arm of chromosome 17 (17p) involving the tumor suppressor TP53 occur in up to 20% of diffuse large B-cell lymphomas (DLBCLs). Although inactivation of both alleles of a tumor suppressor gene is usually required for tumor development, the overlap between TP53 deletions and mutations is poorly understood in DLBCLs, suggesting the possible existence of additional tumor suppressor genes in 17p. Using a bacterial artificial chromosome (BAC) and Phage 1 artificial chromosome (PAC) contig, we here define a minimally deleted region in DLBCLs encompassing approximately 0.8 MB telomeric to the TP53 locus. This genomic region harbors the tumor suppressor Hypermethylated in Cancer 1 (HIC1). Methylation-specific PCR demonstrated hypermethylation of HIC1 exon 1a in a substantial subset of DLBCLs, which is accompanied by simultaneous HIC1 deletion of the second allele in 90% of cases. In contrast, HIC1 inactivation by hypermethylation was rarely encountered in DLBCLs without concomitant loss of the second allele. DLBCL patients with complete inactivation of both HIC1 and TP53 may be characterized by an even inferior clinical course than patients with inactivation of TP53 alone, suggesting a functional cooperation between these two proteins. These findings strongly imply HIC1 as a novel tumor suppressor in a subset of DLBCLs.

Chlamydiae and Mycoplasma infections in pulmonary MALT lymphoma

Chlamydia pneumoniae, Chlamydia trachomatis and Chlamydia psittaci were detected at low frequencies (<20%) among 69 pulmonary mucosa-associated lymphoid tissue (MALT) lymphomas, 30 other lymphoproliferative disorders (LPD) and 44 non-LPD. The incidence of individual Chlamydiae was generally higher in MALT lymphoma than non-LPD, although not reaching statistical significance. Mycoplasma pneumoniae DNA was not detected.

Distinctive patterns of BCL6 molecular alterations and their functional consequences in different subgroups of diffuse large B-cell lymphoma

Gene expression profiling of diffuse large B-cell lymphoma (DLBCL) has revealed biologically and prognostically distinct subgroups: germinal center B-cell-like (GCB), activated B-cell-like (ABC) and primary mediastinal (PM) DLBCL. The BCL6 gene is often translocated and/or mutated in DLBCL. Therefore, we examined the BCL6 molecular alterations in these DLBCL subgroups, and their impact on BCL6 expression and BCL6 target gene repression. BCL6 translocations at the major breakpoint region (MBR) were detected in 25 (18.8%) of 133 DLBCL cases, with a higher frequency in the PM (33%) and ABC (24%) subgroups than in the GCB (10%) subgroup. Translocations at the alternative breakpoint region (ABR) were detected in five (6.4%) of 78 DLBCL cases, with three cases in ABC and one case each in the GCB and the unclassifiable subgroups. The translocated cases involved IgH and non-IgH partners in about equal frequency and were not associated with different levels of BCL6 mRNA and protein expression. BCL6 mutations were detected in 61% of DLBCL cases, with a significantly higher frequency in the GCB and PM subgroups (>70%) than in the ABC subgroup (44%). Exon-1 mutations were mostly observed in the GCB subgroup. The repression of known BCL6 target genes correlated with the level of BCL6 mRNA and protein expression in GCB and ABC subgroups but not with BCL6 translocation and intronic mutations. No clear inverse correlation between BCL6 expression and p53 expression was observed. Patients with higher BCL6 mRNA or protein expression had a significantly better overall survival. The biological role of BCL6 in translocated cases where repression of known target genes is not demonstrated is intriguing and warrants further investigation.

Deficiency of the autoimmune regulator AIRE in thymomas is insufficient to elicit autoimmune polyendocrinopathy syndrome type 1 (APS-1)

Thymomas are thymic epithelial neoplasms, associated with a variety of autoimmune disorders (especially myasthenia gravis), that apparently result from aberrant intra-tumourous thymopoiesis and export of inefficiently tolerized T-cells to the periphery. The autoimmune regulator (AIRE) drives the expression of self-antigens in the thymic medulla and plays an essential role in 'central' tolerance in both humans and mice. However, while inactivating AIRE mutations result in the 'autoimmune polyendocrinopathy syndrome type 1' (APS-1), its major features are not well reproduced in AIRE-knock-out mice. Therefore, alternative human disease scenarios with concomitant AIRE deficiency may be valuable tools to test conclusions drawn from mouse models. Here we show, in a large series, that approximately 95% of thymoma patients are 'chimeric'; expression of AIRE and major AIRE-related autoantigens (eg insulin) were undetectable in their tumours but maintained in their remnant thymic tissue and lymph nodes. Notably, despite the AIRE-deficient thymopoiesis in thymomas, disorders and autoantibodies typical of APS-1 were distinctly uncommon in these patients. The one striking similarity was in the recently observed neutralizing anti-type I interferon (IFN) antibodies, which are found at diagnosis in 100% of patients with APS-1 and in approximately 60% of patients with thymomas, as we show here. We conclude that APS-1 type autoantigens must be protected from autoimmunity by mechanisms that do not extend to the muscle autoantigens so frequently targeted in thymoma patients but so rarely recognized in APS-1. Thus our findings argue strongly for a tolerogenic function of AIRE beyond its role in negative T-cell selection in human thymopoiesis, and/or for specific autoimmunization against muscle in thymomas.

Periphere NK/T-Zell-Lymphome

Peripheral T-cell lymphomas comprise 8% of the malignant lymphomas in Germany. About 25% of these cases present primarily in extranodal localizations. Such localizations are typical for the respective disease and form the basis for the classification of extranodal peripheral T-cell lymphoma. The morphology, immunophenotype and lineage specificity of the tumor cells (originating from T- or NK-cells) is only secondary for the classification. Extranodal NK/T-cell lymphomas of the nasal type are characterized by an angiocentric growth pattern and large confluent areas of necrosis. In addition, there is a clonal infection by Epstein-Barr virus in the T-lymphocytes. In the differential diagnosis, B-cell lymphomas are more frequent at all localizations than T- or NK-cell lymphomas.

Pathologie und Pathogenese des Enteropathie-assoziierten T-Zell-Lymphoms

Enteropathy type T-cell lymphomas (ETL) are the most frequent T-cell lymphomas arising in the gastrointestinal tract. Commonly, the neoplasm is clinically associated with symptoms of malabsorption, and it frequently manifests as a spontaneous bowel perforation. Among ETL, two types can be distinguished by morphology, immunophenotype and, possibly, by pathogenesis. A total of 80% of ETL are characterized by a close association with celiac disease, pleomorphic cytomorphology and the rare expression of CD8 and CD56. In contrast, 20% of ETL show a monomorphic small to medium size cytomorphology and frequent expression of CD8 and CD56, an association with celiac disease is rare in the latter cases. Genetically, ETL is characterized by frequent and recurrent chromosomal gains of 9q33-q34.

[Therapy-relevant mutations of receptor tyrosine kinases in malignant thymomas and thymic carcinomas: a therapeutic perspective]

50-70% of patients with malignant thymic epithelial tumors (thymomas or thymic carcinomas) cannot be cured by current treatment strategies and are therefore candidates for second line therapies.

METHODS

Malignant thymomas and thymic squamous cell carcinomas (TSCC) were analyzed by genomic sequencing and functional tests using ex vivo explant cell cultures to study alterations of the receptor tyrosine kinases c-Kit and epidermal growth factor receptor (EGFR) and their relevance for tumor cell function.

RESULTS

Overexpression of c-Kit was observed only in TSCC, but not in thymomas. In spite of overexpression in almost 90% of TSCC, c-Kit mutations were very infrequent (10%). A strong expression of the EGFR was observed in 70% of thymomas and 35% of TSCC. Mutations of exons encoding extra- or intracellular domains were not observed in a single case (n=40). However, in vitro studies with epithelial explant cell cultures of these tumors suggested that treatment with Cetuximab was effective in a subset of cases, while others were resistant.

CONCLUSIONS

Our findings may forecast therapeutic responses to emerging target treatments in malignant thymomas and thymic carcinomas and may help to develop novel strategies.

[Tumor-type specific translocations methods and indications for routine molecular pathology]

Chromosomal abnormalities like translocations and their corresponding gene fusions were first suggested to be causal factors in the development of cancer by Boveri in 1914. At present more than 350 gene fusions involving 337 different genes have been identified and in particular in malignant hematological diseases and sarcomas an increasing number of chromosomal aberrations are being recognized as important diagnostic and prognostic parameters. By contrast this type of gene rearrangement has been until recently only rarely described in the common carcinomas. However, with new powerful techniques, that enable the detection of cytogenetically cryptic rearrangement, this number is likely to increase substantially and carcinomas characterized by fusions oncogenes indicate that the pathogenetic mechaisms involved in epithelial carcinogenesis may be similar to those known to operate in hematological and soft-tissue malignancies.

[Cutaneous B-cell lymphoma. Classification and diagnostics]

Primary cutaneous B-cell lymphomas include cutaneous follicle centre lymphoma (PCFCL), cutaneous marginal zone B-cell lymphoma (PCMZL) and cutaneous diffuse large B-cell lymphoma (PCLBCL) "leg type" which are the three main types in the new WHO-EORTC classification for cutaneous lymphomas. PCFCL and PCMZL are indolent lymphomas with an excellent prognosis while PCLBCL shows an aggressive clinical course. All three types must be distinguished from a secondary skin involvement by systemic lymphomas. Since histological and immunohistochemical findings are not decisive, making this distinction requires appropriate staging procedures. In contrast, the pathologist can make an important contribution to the differential diagnosis between neoplastic and reactive cutaneous lymphoproliferations.

Nodal peripheral T-cell lymphomas correspond to distinct mature T-cell populations

Peripheral T-cell lymphomas (PTCL) have not been successfully correlated with specific developmental stages of reactive T-cells. Mature T-cells pass through distinct stages upon antigen encounter. Naïve T-cells are CD45RA(+)/CD45R0(-)/CD27(+)/CCR7(+). After antigen contact they replace CD45RA expression with CD45R0. The mature T-cells differentiate to central memory cells, which retain CD27 and CCR7, or to effector memory cells, which lose expression of both molecules depending on the strength of the antigen interaction. In this study, we evaluated lymph node biopsies from eight PTCL-not otherwise specified (PTCL-NOS), seven angioimmunoblastic T-cell lymphomas (AILT), and 15 anaplastic large cell lymphomas (ALCL). Detection of tumour cells with antibodies that recognize specific rearranged T-cell receptor Vbeta segments allowed us to investigate the expression of various differentiation-associated molecules. Results were analysed by hierarchical cluster analysis. All AILT and ALCL showed a homogeneous effector cell phenotype (CD45RA(-)/CD45R0(+)/CD27(-)), but differed in the cytotoxic and activation markers expressed. Several (5/8) PTCL-NOS clustered together; these cases all exhibited a CD4(+) central memory cell phenotype (CD45RA(-)/CD45R0(+)/CD27(+)) and four expressed the lymph node homing receptor CCR7. In conclusion, AILT and ALCL tumour cells correspond to different subsets of effector cells, while a subset of PTCL-NOS correlates with a non-effector T-cell population.

Maligne hämatopoetische Systemerkrankungen

The moleculargenetic detection of specific genetic abnormalities within malignant hematopoietic disorders is an important diagnostic tool with relevance for the differential diagnosis, therapy and prognosis.According to a modified and optimized RT-PCR based technique native bone marrow aspirates and peripheral blood samples of 183 patients were investigated for the presence of specific genetic abnormalities. The histological diagnosis of all CMLs t(9;22) and variants of AMLs M3 t(15;17) and t(11;17) were moleculargenetically confirmed. Additionally one t(5;12) positive chronic myelomonozytic leukemia, one t(8;21) positive AML M1, one t(9;22) positive B-ALL and in each case one t(6;9) and one t(3;21) positive myelodysplastic syndrome were detected. The hereby described method is a simple, specific and reliable technique for the rapid moleculargenetic detection of specific genetic abnormalities within malignant hematopoietic disorders with implication for the diagnosis/differential diagnosis, prognosis and therapy.

Extended field radiotherapy, combined modality treatment or involved field radiotherapy for patients with stage IA lymphocyte-predominant Hodgkin's lymphoma: a retrospective analysis from the German Hodgkin Study Group (GHSG)

BACKGROUND

Since there are no randomized studies, the treatment of choice for patients with early stage lymphocyte-predominant Hodgkin's lymphoma (LPHL) remains unclear. We thus reviewed all LPHL cases registered in the database of the German Hodgkin Study Group (GHSG) and compared the different treatment approaches, such as extended field (EF), involved field (IF) radiation and combined modality (CM) treatment for LPHL stage IA patients.

PATIENTS AND METHODS

One hundred and thirty-one patients with LPHL in clinical stage IA without risk factors were analyzed. Forty-five patients were treated with EF radiotherapy, 45 patients with IF radiation and 41 patients received CM treatment. The median follow-up was 78 months in the EF group, 40 months after CM and 17 months after IF, respectively.

RESULTS

A total of 129 patients achieved complete remission (CR and CRu): 98% after EF radiotherapy, 100% after IF radiation and 95% after CM. With a median follow-up of 43 months there were 5% relapses and only three patients died. Toxicity of treatment was generally mild with most events observed after CM.

CONCLUSION

In terms of remission induction IF radiotherapy for stage IA LPHL patients is as effective as EF or CM treatment. However, longer follow-up is needed before final conclusion as the optimal therapy.

Extrafollicular proliferation of B cells in the absence of follicular hyperplasia: a distinct reaction pattern in lymph nodes correlated with primary or recall type responses

AIMS

Extrafollicular activation of B cells is rarely observed in human lymph nodes. The aim of this study was to extensively analyse the expression of surface molecules and transcription factors in four such cases, comparing them with follicular B cells and medullary cord plasma cells.

METHODS AND RESULTS

Various combinations of B-cell-related surface markers and transcription factors were studied by triple immunofluorescence. While in the germinal centre, reactive immunoglobulin production occurred exclusively in non-proliferating cells, in extrafollicular activation proliferation of B cells and immunoglobulin production coexisted. In two of these cases proliferating cells were mainly IgG+CD27+, i.e. derived from class-switched postgerminal centre memory B cells. Some of these cells expressed CD30. In the other two cases, immunoglobulin-forming cells were non-class-switched IgM+CD27- B cells, representing a primary expansion of naive B cells.

CONCLUSIONS

Extrafollicular B-cell activation is the morphological correlate of rapid B-cell responses that do not involve the germinal centres. It is pathogenetically heterogeneous, comprising primary responses that occur prior to, or independent of, germinal centre reaction or memory cell activation in recall responses.

Composite marginal zone B-cell lymphoma and classical Hodgkin's lymphoma: a clinicopathological study of 12 cases

AIMS

Classical Hodgkin's lymphoma (cHL) rarely coexists as composite lymphoma with B-cell non-Hodgkin's lymphoma (B-NHL). We characterized 12 cases of composite marginal zone B-cell lymphoma (MZBL) and cHL by immunohistochemistry and molecular biology.

METHODS AND RESULTS

Eight patients had gastric MZBL of mucosa-associated lymphoid tissue (MALT)-type, in five cases with a diffuse large B-cell lymphoma component. Concurrent cHL was observed either in the stomach wall, regional, or distant lymph nodes. One patient each had composite pulmonary/thyroid MZBL of MALT-type and cHL. In two cases, nodal composite MZBL and cHL was observed. cHL displayed features of mixed cellularity type in 10 cases, while in two cases only scattered Hodgkin- and Reed-Sternberg (H/RS) cells were noted. H/RS cells expressed CD30, multiple myeloma oncogene 1 protein (MUM1P), p53 (100%), CD15 (58%), CD20 (58%) and Epstein-Barr virus-associated LMP1 (50%). No t(11;18)(q21;q21) was detected in composite MZBL of MALT-type and cHL.

CONCLUSIONS

MZBL and cHL may occur as composite lymphoma, possibly reflecting clonal lymphoma progression. Derivation from extranodal MZBL of MALT-type should be excluded in cases in which a diagnosis of primary extranodal cHL is considered.

Chronic non-bacterial osteomyelitis in children

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) in children is a chronic non-suppurative inflammation involving multiple sites. Some children affected by chronic non-bacterial osteomyelitis (CNO) do not have multiple lesions or a recurrent course.

OBJECTIVE

To characterise the long term outcome of children with the full spectrum of CNO.

METHODS

30 children diagnosed with CNO were followed up for a mean of 5.6 years and their disease assessed using a clinical score, multiple imaging, and a diagnostic biopsy, including extensive microbial analysis.

RESULTS

9 patients had unifocal non-relapsing disease, 3 unifocal lesions with relapses, 9 multifocal lesions without relapses, and 9 multifocal lesions with relapses (CRMO). Granulocytes were present significantly more often in CRMO than in unifocal and non-recurrent lesions. Pustulosis was more common in multifocal cases regardless of recurrence. Mean duration of treatment in 15 children with a single occurrence was 9.2 months. Naproxen treatment was generally effective. Naproxen treatment in 12 patients with relapses lasted 25 months. However, 7 of these were not effectively treated with naproxen alone. Five were treated with oral glucocorticoids for 27 days in addition to naproxen, which induced remission in four, lasting for at least 1.5 years. Longitudinal growth of affected bones was not altered, except for the development of hyperostosis.

CONCLUSION

CNO is a spectrum of inflammatory conditions, with CRMO being the most severe. Most children with CNO have a favourable outcome of the disease. Oral glucocorticoids may be necessary in severe recurrent cases.

[Anaplastic large cell lymphomas lack the expression of T-cell receptor molecules]

Anaplastic large cell lymphoma (ALCL) designates a heterogeneous group of CD30+ (systemic or primary cutaneous) peripheral T-cell lymphomas (PTCLs). A subgroup of systemic ALCL is transformed by anaplastic lymphoma kinase (ALK). We compared 46 ALCL with 22 PTCLs in terms of T-cell receptor (TCR) rearrangements, expression of TCRs and TCR-associated molecules [CD3, ZAP-70 (zeta-associated protein 70)]. Despite their frequent clonal rearrangement for TCRbeta, only 4% of ALCLs expressed TCRbeta protein, whereas TCRs were detected in 86% of PTCLs. Moreover, both TCRbeta+ ALCLs lacked CD3 and ZAP-70 (ie, molecules indispensable for the transduction of cognate TCR signals). Defective expression of TCRs is a common characteristic of all types of ALCL, which may contribute to the dysregulation of intracellular signaling pathways controlling T-cell activation and survival. This molecular hallmark of ALCL is analogous to defective immunoglobulin expression distinguishing Hodgkin lymphoma from other B-cell lymphomas.

A prospectively randomized trial carried out by the German Hodgkin Study Group (GHSG) for elderly patients with advanced Hodgkin's disease comparing BEACOPP baseline and COPP-ABVD (study HD9elderly)

In contrast to younger patients, the prognosis of elderly patients with advanced Hodgkin's disease (HD) has not improved substantially over the last 20 years. We thus carried out a prospectively randomized study (HD9(elderly)) to compare the BEACOPP regimen in this setting against standard COPP-ABVD. Between February 1993 and 1998, 75 patients aged 66-75 years with newly diagnosed HD in advanced stages were recruited into the HD9 trial as a separate stratum (HD9(elderly)). Patients were assigned to eight alternating cycles of COPP and ABVD or eight cycles of BEACOPP in baseline doses. Radiotherapy was given to initial bulky or residual disease. In total, 68 of 75 registered patients were assessable: 26 were treated with COPP-ABVD and 42 with BEACOPP baseline. There were no significant differences between COPP-ABVD and BEACOPP in terms of complete remission (76%), overall survival (50%) and freedom from treatment failure (FFTF) (46%) at 5 years. At a median follow-up of 80 months, a total of 37 patients died: 14/26 patients (54%) treated with COPP-ABVD and 23/42 patients (55%) with BEACOPP. Two patients (8%) treated with COPP-ABVD and nine patients (21%) treated with BEACOPP died of acute toxicity. Hodgkin-specific FFTF at 5 years was 55% after COPP-ABVD and 74% after BEACOPP (P=0.13). Thus, there are no differences in survival between these regimens in elderly patients.

Vermeintliches Adenokarzinom des Samenstranges

Malignant tumors of the spermatic cord are rare with primary neoplasms being mostly sarcomas. Adenocarcinomas of the spermatic cord are found extremely seldom and are predominantly metastases of extragonadal tumors. We present an asymptomatic 47-year-old patient who was referred to our clinic after a vasectomy had been performed and the histological examination had surprisingly shown adenocarcinoma of the left spermatic cord. Extensive laboratory analysis and diagnostic imaging did not demonstrate any testicular, spermatic cord, or extragonadal tumor. To exclude a mix-up of specimens, we performed DNA analysis. Microsatellite PCR clearly demonstrated the different origins of the tumor and the vasectomy specimen. Specimen mix-up or contamination may happen in any phase of surgical or pathological processing. In any case of clinical uncertainty concerning the identity of a tissue specimen, this possibility has to be taken into consideration. Microsatellite PCR can clearly identify the origin of tissue samples even on embedded material.

[Isolated Rosai-Dorfman disease]

A case of extranodal sinus histiocytosis with massive lymphadenopathy (ENSHML; Rosai-Dorfman disease) is reported. The patient presented with a history of intracranial tumour and exophthalmus. Clinical examination found a large mass in the left orbit and paranasal sinuses. Excisional biopsy showed a dense fibrous tissue with an infiltrate rich in macrophages. Further evaluation revealed a retroperitoneal mass with consecutive ureteral stenosis. Further histological and immunohistochemical investigation of the orbital mass, now in suspicion of a systemic disease showed an infiltrate of S-100-positive histiocytes and emperipolesis allowing the diagnosis of extranodal sinus histiocytosis. The correct histologic diagnosis was delayed due to the unusual and isolated extranodal localisation of the disease. The literature concerning extranodal manifestations of Rosai-Dorfman disease is reviewed. We suggest the additional evaluation of such rare and unusual cases in experienced reference centers.

Centrosome aberrations as a possible mechanism for chromosomal instability in non-Hodgkin's lymphoma

Recently, centrosome aberrations have been described as a possible cause of aneuploidy in many solid tumors. To investigate whether centrosome aberrations occur in non-Hodgkin's lymphoma (NHL) and correlate with histologic subtype, karyotype, and other biological disease features, we examined 24 follicular lymphomas (FL), 18 diffuse large-B-cell lymphomas (DLCL), 33 mantle cell lymphomas (MCL), and 17 extranodal marginal zone B-cell lymphomas (MZBCL), using antibodies to centrosomal proteins. All 92 NHL displayed numerical and structural centrosome aberrations as compared to nonmalignant lymphoid tissue. Centrosome abnormalities were detectable in 32.3% of the cells in NHL, but in only 5.5% of lymphoid cells from 30 control individuals (P<0.0001). Indolent FL and MZBCL contained only 25.8 and 28.8% cells with abnormal centrosomes. In contrast, aggressive DLCL and MCL harbored centrosome aberrations in 41.8 and 35.0% of the cells, respectively (P<0.0001). Centrosomal aberrations correlated to lymphoma grade, mitotic, and proliferation indices, but not to the p53 labeling index. Importantly, diploid MCL contained 31.2% cells with abnormal centrosomes, while tetraploid samples harbored centrosome aberrations in 55.6% of the cells (P<0.0001). These results indicate that centrosome defects are common in NHL and suggest that they may contribute to the acquisition of chromosomal instability typically seen in NHL.

Hepatoid Thymic Carcinoma

We describe the clinicopathologic findings in a so far unrecognized thymic tumor. The tumor occurred in a 70-year-old woman with respiratory distress but neither myasthenia gravis nor other symptoms. Metastases or another primary tumor were absent. The well-circumscribed neoplasm was located in the thymic region, measured 18 x 12 x 8 cm, and showed a homogeneous, tan-colored, soft cut surface. By histology, the tumor lacked a true capsule and a lobular growth pattern, was almost devoid of stroma, and infiltrated among remnant thymus lobules. The polygonal tumor cells formed solid sheets, trabeculae, or occurred as single cells that resembled hepatocytes. Proliferative activity was low. Portal structures, sinuses, and bile were absent as were areas of conventional thymoma, adenocarcinoma, or germ cell tumor. The tumor expressed cytokeratins 7 and 19, alpha1-antitrypsin, alpha1-antichymotrypsin, and hep-Par-1. Alpha-fetoprotein (AFP), human beta-chorionic gonadotropin (beta-HCG), placental alkaline phosphatase, CD5, CD30, CD31, CD34, CD45, CD68, CD99, S-100, HMB45, desmin, actin, or neuroendocrine markers were not expressed, and intratumorous CD1a+ or TdT+ immature T cells were absent. AFP was repeatedly undetectable in the blood. Mediastinal tumor recurrence was detected 6 months after surgery. Following radiochemotherapy, the patient has remained free of disease for 26 months. We conclude that this tumor is a thymic carcinoma (WHO type C thymoma). A diagnosis of hepatoid yolk sack tumor appears unlikely considering absence of a bona fide germ cell component, lack of AFP expression, and the patient's female gender. Because of its morphologic and immunohistochemical features, we propose the term "hepatoid thymic carcinoma" for this new type of thymic carcinoma.

Pleiotropic effects of CXC chemokines in gastric carcinoma: differences in CXCL8 and CXCL1 expression between diffuse and intestinal types of gastric carcinoma

CXC chemokines modulate host immunity, neovascularization, growth and invasive behaviour of tumours. Despite their relevance in tumour biology, chemokine expression in intestinal- and diffuse-type gastric carcinoma, which exhibit a completely different growth pattern, has not been investigated in detail. In this study, expression of the CXC chemokines CXCL8 [interleukin (IL)-8], CXCL1 [growth-related oncogene alpha (Gro alpha)], CXCL9 [monokine induced by interferon (IFN)-gamma] and CXCL10 [IFN-gamma-inducible protein-10 (IP-10)] and the corresponding chemokine receptors CXCR1-3 was investigated by immunohistochemistry in intestinal- and diffuse-type gastric carcinoma. Tumour cells of all patients expressed CXCL8. CXCL8 expression was significantly stronger in tumour cells of diffuse- rather than intestinal-type gastric carcinoma (P < 0.01) as determined by a semiquantitative score. CXCL1 was expressed almost exclusively by diffuse- but not intestinal-type carcinoma cells. The corresponding chemokine receptors, CXCR1 and CXCR2, were found on carcinoma cells. Furthermore, CXCL8 expression correlated with number of tumour vessels (P < 0.01), suggesting an angiogenetic function in gastric carcinoma not only in vitro but also in vivo. CXCL10 and CXCL9, attractants for T cells, were expressed by peritumorous macrophages in close proximity to IFN-gamma-producing CXCR3-positive T cells in both tumour types. These chemokines may attract gastric carcinoma-infiltrating T cells via an IFN-gamma-mediated pathway and enhance host immunity against the tumour. In gastric carcinoma a complex interplay between CXC-chemokine signals derived from both tumour cells and tumour-infiltrating immune cells may exhibit pleiotropic effects in tumour biology that go far beyond their originally described functions as leucocyte chemoattractants. Because CXCL8 and CXCL1, which are known to increase growth and invasive behaviour of malignant tumours, are significantly stronger expressed in diffuse- than intestinal-type gastric carcinoma, one may speculate that these chemokines influence the different growth pattern of gastric carcinoma types.

[The overexpression of NCAM (CD56) in human hearts is specific for ischemic damage]

The main reason for myocardial dysfunction is chronical myocardial ischemia. Recently we could show, that NCAM (CD56), a neural cell adhesion molecule and member of the immunoglobuline superfamily, and the transcription factor AML1 (RUNX1) are overexpressed in chronic ischemic human heart failure compaired to normal hearts. Here we demonstrate, that the overexpression of NCAM (CD56) is specific for ischemic damage as compaired to other heart diseases including congestive cardiomyopathy, hypertrophic obstrutive cardiomyopathy, myocarditis and sarcoidosis. Concerning the transcriptional regulation of NCAM (CD56) by AML1 (RUNX1) we isolated 3 novel isoforms of AML 1 (RUNX1) with different transactivating function, that might be a regulatory element of the NCAM (CD56) overexpression in chronical myocardial ischemia.

[The spectrum of lymphoproliferations and malignant lymphoma after organ transplant]

Lymphoproliferative disease in patients with organ transplantation has increasingly been diagnosed in recent years. It is caused by immunosuppression after organ transplantion. A large percentage of these tumors is associated with Epstein-Barr virus infection. The classification differentiates between early lesions, polymorphic and monomorphic lymphoproliferations. Whereas the early lesions are often polyclonal, the remaining groups are mostly monoclonal. Polymorphic lymphoproliferative disease shows a wide spectrum of B-cell differentiation, whereas monomorphic proliferations resemble sproadic malignant lymphomas. The latter also show genetic abberations of the c-myc-, Ras-, p53- and Bcl6-genes. With reference to the germinal center reaction, posttransplant lymphoproliferations have to be assigned to the post-follicular activated B-cell type. While until 1991 only 2% of the cases of PTLD had an EBV-association, the EBV-associated PTLD have been frequently observed in recent times and presently constitute about 20% of the cases. EBV-negative PTLD constitute a negative prognostic factor. Posttransplant lymphomas might also represent a model for sporadic lymphoproliferative disease, that for example also occurs at elderly patients.

14-day variant of the bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone regimen in advanced-stage Hodgkin's lymphoma: results of a pilot study of the German Hodgkin's Lymphoma Study Group

PURPOSE

This multicenter pilot study assessed the feasibility and efficacy of a time-intensified bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP) regimen given in 14-day intervals (BEACOPP-14) with granulocyte colony-stimulating factor (G-CSF) support in advanced Hodgkin's lymphoma.

PATIENTS AND METHODS

From July 1997 until March 2000, 94 patients with Hodgkin's lymphoma stage IIB, III, and IV were scheduled to receive eight cycles of BEACOPP-14. Consolidation radiotherapy was administered to regions with initial bulky disease or residual tumor after chemotherapy.

RESULTS

All patients were assessable for toxicity and treatment outcome. Eighty-six patients received the planned eight cycles of BEACOPP-14. Consolidation radiotherapy was given in 66 patients. Chemotherapy could generally be administered on schedule. Dose reductions varied among drugs but were generally low. Acute toxicity was moderate, with World Health Organization grade 3/4 leukopenia in 75%, thrombocytopenia in 23%, anemia in 65%, and infection in 12% of patients. A total of 88 patients (94%) achieved a complete remission. Four patients had progressive disease. At a median observation time of 34 months, five patients have relapsed, one patient developed a secondary non-Hodgkin's lymphoma, and three deaths were documented. The overall survival and freedom from treatment failure rates at 34 months were 97% (95% confidence interval [CI], 93% to 100%) and 90% (95% CI, 84% to 97%), respectively.

CONCLUSION

Acceleration of the BEACOPP baseline regimen by shortening cycle duration with G-CSF support is feasible and effective with moderate acute toxicity. On the basis of these results, the German Hodgkin's Lymphoma Study Group will compare the BEACOPP-14 regimen with BEACOPP-21 escalated in a prospective multicenter randomized trial.

Malignant thymoma: current status of classification and multimodality treatment

Classification, understanding of the pathophysiology, and treatment options of thymoma have changed during recent years. It is hoped that novel strategies will lead to a survival benefit in these patients. It has become clear that patients with thymoma are best treated with multimodality therapy. In this review, a pathologist, an immunologist, a surgeon, a radiotherapist, a pneumologist, and oncologists discuss the current status of classification and strategies for the treatment of patients with thymoma.

[WHO-classification of malignant lymphomas]

Because of the multiple developmental stages of lymphocytes and the complexity of the immune system,the corresponding neoplasms, the malignant lymphomas, represent a complex group of diseases. The clinical grouping of the KIEL-classification, distinguishing high grade from low grade lymphomas, has been abandoned in the WHO-classification as it is partly misleading. Especially,mantle cell lymphoma which, according to its morphology, represents a low grade lymphoma, is characterized by an extremely aggressive clinical course. The therapy of malignant non-Hodgkin lymphomas has become more and more diverse. The great advances in survival and quality of life of patients with malignant lymphomas have been reached in multiple clinical studies to optimize therapy and simultaneously set up standards of quality for the diagnosis and therapy of malignant lymphoma (see http://www.lymphome.de). Especially in the group of so-called low grade lymphomas according to the KIEL-classification, clinical studies in Germany follow different therapy concepts for each of the diseases. Therefore,patients should be treated within such a study.

Quality assurance in immunohistochemistry: results of an interlaboratory trial involving 172 pathologists

The practicability of quality assurance in immunohistochemistry and its integration into the diagnostic process were both tested in this Germany-wide interlaboratory trial. One hundred seventy-two pathologists received one hematoxylin and eosin and five unstained slides from five cases; all cases were selected by a panel because immunohistochemistry was required for their final diagnosis. Participants rendered a morphologic diagnosis and then substantiated it immunohistochemically. Stained slides and evaluation sheets were reviewed by the panel, and the diagnostic process was analyzed in individual steps: morphologic diagnosis, selection of antibodies, staining quality, interpretation of stained slides, conclusions, and final diagnosis. Diagnosis-independent immunohistochemical performance was tested using a multisample tissue block (30 samples) that was stained and evaluated for six common antigens. For individual cases, corresponding to their difficulty, 21-89% of the final diagnoses (altogether 57% from 828 diagnoses) were correct. In a statistical analysis, the tentative diagnosis, the interpretation of stains and conclusions drawn from immunohistochemistry, were independent factors in reaching the diagnosis. Sensitivity to detect estrogen receptors on the multisample tissue block was only 48%. However, 24% of the stains were interpreted as falsely negative. The low staining sensitivity was not correlated to the number of correct diagnoses. The major problem of applying immunohistochemistry in surgical pathology appears to be its integration into the diagnostic process and not the staining quality. Both future quality control projects and training will have to regard these integrative requirements. Multisample tissue blocks provide a promising tool to standardize quantitative immunohistochemical parameters, such as receptor or proliferation scores.

Splenectomy in patients with mixed myelodysplastic/myeloproliferative disease

According to the classification of the World Health Organization, the designation myelodysplastic/myeloproliferative disorder, unclassifiable may be applied to cases that have clinical, laboratory, and morphologic features that support a diagnosis of a myelodysplastic syndrome (MDS) as well as a myeloproliferative disorder (MPD), but that do not meet the criteria for any of the other entities included in the MDS/MPD category [3]. In this paper we report on two Caucasian patients with unclassifiable myelodysplastic syndromes with proliferative characteristics. Both patients were suffering from thrombocytopenia and splenomegaly and underwent splenectomy. The weight of the spleen specimens was more than 2000 g. Histopathology findings revealed a marked infiltration of the spleen with extramedullary hematopoiesis. After surgery, one patient showed a rapid increase of platelets in peripheral blood and developed severe thrombocytosis. In the other case, the patient was suffering from a decrease of platelets and died in hypovolemic shock caused by gastrointestinal bleeding. In summary, these two cases demonstrate the difficulties of prognosis and treatment in patients with mixed myelodysplastic/myeloproliferative disorders. Additionally, we indicate the potential positive outcome of splenectomy as ultima ratio in patients with these hematological features and severe thrombopenia.

Deactivation of regulatory proteins hnRNP A1 and A2 during SC-1 induced apoptosis

Phosphorylation and activation of caspases play an important role in the induction of apoptosis. During tumor specific apoptosis, induced by the human monoclonal antibody SC-1, tyrosine phosphorylation and serine dephosphorylation of several proteins is observed. In this paper we describe the identification of two dephosphorylated proteins as heterogeneous nuclear ribonucleoproteins A1 and A2 (hnRNP A1, hnRNP A2). The dephosphorylation of these proteins is important for apoptosis since the amount of apoptotic cell death can be decreased by the specific serine/threonine phosphatase inhibitor okadaic acid. We also investigated the effect of serine kinase inhibitor H7 on SC-1 induced apoptosis, which leads to a dose dependent increase in apoptosis. We could also show that 24 hours after the induction of apoptosis the hnRNP A1 protein is cleaved into different cleavage products. Further, we found a decreased expression of caspase-2 in early apoptosis signalling and an overexpression 24 hours after induction of apoptosis. Our results show that the phosphorylation status of the hnRNP A1 and A2 plays a significant role in early SC-1 induced apoptosis signalling and further indicate the role of caspase activation during the apoptotic process.

Diffuse large B-cell lymphoma: a clinicopathologic analysis of 444 cases classified according to the updated Kiel classification

The purpose of this study was: to compare the survival of diffuse large B-cell lymphomas (DLBCL) stratified according to the up-dated Kiel classification. A retrospective study of a cohort of 1378 cases was organized in 1996 by the Non-Hodgkin's Lymphoma Classification Project, and the DLBCL were classified according to the updated Kiel classification. The distribution of the different types and subtypes was as follows: centroblastic (CB, 85.4%), composed of the polymorphic (CB-PM, 58.6%), monomorphic (CB-MM, 17.1%) and multilobated (CB-ML, 9.7%) subtypes; immunoblastic (IB, 11.2%), with (8.3%) or without (2.9%) plasmacytoid differentiation; and anaplastic large cell lymphoma (ALCL) of B-cell type (3.4%). The rate of diagnostic agreement between pathologists was 78% for CB and 65% for IB lymphoma. The 5-year overall survival (OAS) for the entire group was 47% and the 5-year failure-free survival (FFS) was 42%. No significant differences in survival were found between the three major groups (CB, IB, ALCL). However, the 5-year OAS and FFS of patients with DLBCL not containing immunoblasts (CB-MM+CB-ML) was 51 and 52%, respectively, and was significantly better than the survival of those containing immunoblasts (CB-PM+IB+ALCL), which was 44 and 38% (p = 0.06 and p = 0.037), respectively. These results did not appear to be due to differences in the clinical features of the two groups, and was most significant for patients with low stage or low risk disease. However, histologic subtyping was not an independent risk factor for the entire group by multivariate analysis. In conclusion, patients with CB-MM and CB-ML (without immunoblasts) had a significantly better OAS and FFS than those with CB-PM, IB and ALCL (with immunoblasts). Therefore, we conclude that additional studies are still needed to further evaluate the importance of immunoblastic differentiation in DLBCL.

Peripheral T-cell lymphoma (excluding anaplastic large-cell lymphoma): results from the Non-Hodgkin's Lymphoma Classification Project

BACKGROUND

Peripheral T-cell lymphoma (PTCL) is rare in most parts of the world. Therefore, we have evaluated the 96 cases of PTCL diagnosed within the Non-Hodgkin's Lymphoma Classification Project (NHLCP) (1378 cases) for their geographical distribution, pathologic features and diagnostic reliability, as well as clinical presentation and outcome.

MATERIALS AND METHODS

Diagnoses of all cases were rendered independently by five experienced hematopathologists based on morphology only, and after introduction of the immunophenotype and clinical data. Divergent diagnoses were jointly discussed and a final consensus diagnosis was established in each case. Reliability of the diagnoses was evaluated statistically, and the clinical features and outcome were analyzed according to the consensus diagnoses.

RESULTS

Seven per cent of all non-Hodgkin's lymphoma (NHL) cases reviewed were classified as PTCL and the frequency varied from 1.5% to 18.3% in different countries. The interobserver agreement with the consensus diagnosis of PTCL was 86% in the Revised European-American Lymphoma (REAL) classification, but the designation of subtypes was less reliable. Diagnostic reliability improved from 41% to 86% after immunophenotyping, but did not improve further with the addition of detailed clinical data. Clinically, angiocentric nasal lymphoma presented in young females (median age 49 years) at extranodal sites, but with few adverse risk factors, whereas angioimmunoblastic lymphoma presented most often in older males (median age 65 years) at nodal and extranodal sites with numerous risk factors. The 5-year overall and failure-free survivals for patients with PTCL treated with doxorubicin (Adriamycin)-containing regimens were only 26% and 20%, respectively. Both failure-free and overall survival were strongly correlated with the performance status and International Prognostic Index scores at presentation, but differences in survival were not observed between the major histological types. However, within the PTCL 'not otherwise specified' category, but not angioimmunoblastic lymphoma, the number of transformed blasts was prognostically relevant.

CONCLUSIONS

PTCLs can be diagnosed reliably by experienced hematopathologists, but immunophenotyping is absolutely necessary. Currently, all types of PTCL should be considered high-grade lymphomas. An increased ability to distinguish T-lymphocyte subsets is needed in order to better subclassify the PTCLs for therapeutic and prognostic purposes.