Detection of gastric MALT lymphoma spreading to the small bowel by enteroscopy.

Mucosa-associated lymphoid tissue (MALT) lymphoma is thought to be a multifocal disease with sometimes synchronous involvement of various mucosal structures. In this study we aimed to evaluate the potential involvement of the small bowel in patients suffering from gastric MALT lymphoma by analyzing the results of enteroscopy, a technique that allows easy and safe access to the small bowel with the potential for histological assessment of biopsy samples. We have retrospectively evaluated 347 enteroscopies and found nine patients with gastric MALT lymphoma who had undergone push enteroscopy with serial biopsies during staging. All patients tolerated enteroscopy without side effects, and no local complications occurred. In eight cases no evidence of duodenal or jejunal involvement was found macroscopically or by histological assessment of biopsies, while in one patient enteroscopy revealed jejunal MALT lymphoma infiltration with macroscopic accentuation of mucosal parts and consecutive histopathological verification more distal than 50 cm. This single-center retrospective analysis shows that enteroscopy can provide additional diagnostic information in patients with gastric MALT lymphoma, although the number of patients was small and only one out of nine patients showed hitherto undetected MALT lymphoma deposits. Further studies may quantify the additional diagnostic yield provided by this easy and safe endoscopic method.

Methotrexate-induced primary cutaneous diffuse large B-cell lymphoma with an 'angiocentric' histological morphology.

A patient with a 25-year history of rheumatoid arthritis and a 3-year history of methotrexate treatment developed a generalized papular rash. The papules rapidly became necrotic and then resolved, leaving a depressed scar. The rapid course of lesion development and regression was reminiscent of pityriasis lichenoides. Histology revealed a nodular infiltrate composed of a mixture of pleomorphic large B cells positive for CD20, CD30 and CD79a, and of small T cells positive for CD3 and CD4. The T cells had a striking angiocentric distribution, with some of the vessels exhibiting fibrinoid necrosis of the vessel wall reminiscent of lymphomatoid granulomatosis. However, B cells were consistently negative for Epstein-Barr virus (EBV) antigen expression. A thorough examination excluded involvement of organs other than the skin. Thus, this patient was classified as having a rare form of an EBV-negative primary cutaneous T-cell-rich B-cell lymphoma in association with methotrexate treatment.

Somatostatin receptor scintigraphy in primary cutaneous T- and B-cell lymphomas.

BACKGROUND: Monitoring and repeated staging is of substantial importance in many patients with primary cutaneous T-cell lymphomas (CTCL). For primary cutaneous B-cell lymphomas (CBCL), extensive initial staging is the mainstay for correct diagnosis. AIM: To evaluate the value of somatostatin receptor scintigraphy using the radiolabeled somatostatin analog (111)In-pentetreotide in comparison to conventional imaging methods for the staging of patients with primary CTCL and primary CBCL. METHODS: Twenty-two patients (15 patients with histologically verified CTCL and 7 patients with histologically verified CBCL) were included. Stage of disease was established by physical examination, laboratory screening, skin inspection, palpation of superficial lymph nodes, sonography and computed tomography (CT) in patients with advanced clinical stage. Focally elevated tracer uptake of (111)In-pentetreotide was compared to common imaging modalities, physical aspect and digital photographs of the respective skin lesions. RESULTS: Of the 15 patients with CTCL, only 4 (27%) showed positive scintigraphic results, but not in all sites of lymphomatous involvement. None of the five patients with mycosis fungoides in stage I, nor any of the four patients with Sézary syndrome, had a positive (111)In- pentetreotide scan. Of the seven patients with CBCL three positive scintigraphic results (43%) could be obtained: in two patients with a follicular center lymphoma and one patient with a diffuse large B-cell lymphoma - leg type, but again not in all apparent sites of lymphoma. CONCLUSIONS: Based on our results, we do not recommend the use of somatostatin receptor scintigraphy for routine staging of patients with CTCL and CBCL. As our series includes only 22 patients, and the number of patients with rarer variants of CTCL was rather small, it might be too premature to abandon SST-R in the staging of patients with cutaneous lymphomas.

Rituximab monotherapy for primary cutaneous B-cell lymphoma: response and follow-up in 16 patients.

BACKGROUND: We have carried out a retrospective analysis to evaluate the therapeutic value of the anti-CD20 antibody rituximab in 16 consecutive patients with primary cutaneous CD20+ B-cell lymphomas. PATIENTS AND METHODS: Sixteen patients (4 females, 12 males) with a median age of 54 years received systemic therapy with rituximab 375 mg/m(2) once weekly for four or six consecutive weeks. Eleven patients had primary cutaneous follicle center cell lymphoma and five patients had a primary cutaneous marginal zone B-cell lymphoma. RESULTS: Of the 16 patients with PCBCL, 14 patients (87.5%) achieved complete remission (CR). In two patients, partial remission was obtained and additional focal radiotherapy was applied, which resulted in final CR. Five to 14 (35%) patients with CR relapsed, in an interval between 6 and 37 months. There were no severe side-effects. CONCLUSIONS: On the basis of our results, single-agent treatment with i.v. rituximab appears to be feasible and safe and results in a high rate of durable remissions. Judging from our data, it appears to be an attractive treatment option and should be directly compared with local radiotherapy.

Mechanisms underlying acquired von Willebrand syndrome associated with an IgM paraprotein.

Acquired von Willebrand (vW) syndrome is a rare bleeding disorder which is frequently associated with immunological, malignant or cardiovascular disorders. The underlying pathomechanisms, particularly in patients with IgM monoclonal gammopathies, often remain unknown. We report a patient with indolent small B-cell lymphoma (immunocytoma) and plasmacytic differentiation with an IgM kappa paraprotein who was admitted with retroperitoneal haematoma. Medical history and coagulation testing were consistent with acquired vW syndrome. vW immunohistochemistry showed normal cytoplasmic labelling of endothelial cells and megakaryocytes, whereas the lymphomatous infiltrate was negative. Acquired vW syndrome due to adsorption of vW factor on malignant cells was thus excluded. In the multimeric analysis, all multimers were present similar to that in type 1 vW syndrome, but the triplet structures were blurred. The bands on serum immunofixation electrophoresis were also atypically broadened, which suggested complex formation between the IgM and vW factor. Immunoprecipitation studies showed that the 176-kDa proteolytic fragment of vW factor co-precipitated with the IgM paraprotein in the patient but not in the controls, suggesting a specific interaction between vW factor and the paraprotein in the patient. The patient required surgery and was successfully managed by chemotherapy consisting of rituximab and fludarabin as well as plasma exchange.

Chronic autoimmune thyroiditis (Hashimoto's thyroiditis) in patients with MALT lymphoma.

BACKGROUND: Autoimmune diseases have been implicated in the genesis of MALT lymphoma of various localizations. The development of thyroidal MALT lymphoma has been described as an adverse event in patients suffering from long-standing chronic autoimmune thyroiditis (CAT, Hashimoto's thyroiditis). The percentage and possible association between CAT and extrathyroidal MALT lymphoma, however, have not been assessed so far. PATIENTS AND METHODS: A retrospective analysis of 80 patients with MALT lymphoma diagnosed and treated at our institution identified a total of 13 patients (16%) with MALT lymphoma suffering from an underlying CAT. Patient characteristics including site of disease, stage, genetic changes and clinical course were assessed and evaluated. RESULTS: In total, 10 patients were female and 3 male, with the median age being 57 years (range: 31-80). Four patients suffered from thyroidal lymphoma and nine patients had extrathyroidal lymphoma (four gastric, two orbital, one small intestinal and two salivary gland lymphomas). Three patients had a long-standing history of CAT at diagnosis of MALT lymphoma, while CAT was discovered during staging and clinical work-up of MALT lymphoma in the remaining 10 patients. All 13 patients had localized disease, i.e. stage I or II. Only one of the four patients with gastric MALT lymphoma responded to antibiotic treatment against Helicobacter pylori infection. Genetic aberrations were detected in four patients, two of whom had a t(11;18)(q21;q21) translocation, one patient had trisomies 3 and 18 and one had trisomy 18. CONCLUSION: Our findings suggest that CAT is found in patients with not only thyroidal but also nonthyroidal MALT lymphoma. While the nature of our data does not allow for delineation of a direct association between CAT and development of extrathyroidal MALT lymphoma, further prospective studies on this issue are warranted.

MALT lymphoma in patients with autoimmune diseases: a comparative analysis of characteristics and clinical course.

MALT lymphoma, especially of extragastric origin, is thought to be associated with an underlying autoimmune disease (AD) in a significant proportion of patients. No systematic assessment of the clinical characteristics of MALT lymphoma arising in AD as opposed to patients without AD has been performed so far. Therefore, all patients diagnosed and treated for MALT lymphoma at our institution have prospectively undergone routine clinical and serological assessment for AD since 1997. In total, 158 patients were available for analysis, and 61 out of 158 patients (39%) were diagnosed with an underlying AD. Patients with AD were predominantly women and significantly younger at lymphoma diagnosis (56 versus 67 years, P=0.004), with a significantly higher rate of extragastric lymphomas (P=0.012). Furthermore, lymphomas in these patients showed a lower frequency of trisomy 3 (P=0.04) and a significantly lower response rate to Helicobacter pylori eradication therapy in the case of gastric lymphomas (P=0.03). All other parameters including estimated median time to relapse were comparable between both groups. Our data suggest that patients with AD develop MALT lymphoma significantly earlier in life. The clinical course, however, does not appear to be adversely influenced by the presence of AD, as neither rate of relapse nor times to relapse or survival are significantly different.

Pathology and clinical course of MALT lymphoma with plasmacytic differentiation.

BACKGROUND: The feature of plasmacytic differentiation (PCD) is present in up to 30% of patients diagnosed with mucosa-associated lymphoid tissue (MALT) lymphoma. To date, the influence of PCD on the clinical course of MALT lymphoma has not been assessed. PATIENTS AND METHODS: Therefore, we have retrospectively analysed the clinical characteristics and the course of the disease in 34 (25%) patients with PCD as compared with 101 (75%) MALT lymphoma patients without this histological feature. RESULTS: Patients with PCD had significantly more extragastric lymphomas [28 of 34 (82%) versus 54 of 101 (53%), P = 0.003] and a significantly lower rate of t(11;18) [2 of 26 (8%) versus 22 of 72 (31%), P = 0.02]. There was no significant difference of age at diagnosis (62 versus 64 years, P = 0.64), relapse rate (48% versus 37%, P = 0.27), estimated median time to progression (43 versus 65 months, P = 0.14), monoclonal gammopathy (50% versus 44%, P = 0.63), t(14;18) involving IGH/MALT 1 (11% versus 8%, P = 0.68), trisomy 3 (31% versus 27%, P = 0.69), trisomy 18 (8% versus 10%, P = 0.74) and the presence of autoimmune diseases between both groups (53% versus 37%, P = 0.09). CONCLUSION: In conclusion, we found that PCD is predominantly found in extragastric MALT lymphoma but has no significant impact on clinical course and prognosis.

Novel t(5;9)(q33;q22) fuses ITK to SYK in unspecified peripheral T-cell lymphoma.

Among peripheral T-cell lymphomas (PTCL), the heterogeneous category of unspecified PTCL represents the most common subtype. Nevertheless, recurrent chromosomal translocations are unknown in this aggressive type of lymphoma. Here we describe a novel t(5;9)(q33;q22) in unspecified PTCL. Molecular analyses delineated the breakpoints to ITK and SYK resulting in a previously undescribed expression of the Syk tyrosine kinase by Itk. ITK-SYK transcripts were detected in five of 30 (17%) unspecified PTCL, but not in cases of angioimmunoblastic T-cell lymphoma (n=9) and anaplastic lymphoma kinase-negative anaplastic large-cell lymphoma (n=7). In all five translocation-positive cases, the breakpoints were identical fusing the N-terminal pleckstrin homology domain and proline-rich region of ITK to the tyrosine kinase domain of SYK. Three of the five t(5;9)(q33;q22)+ unspecified PTCL shared a very similar histological pattern with predominant involvement of lymphoid follicles and the same CD3+CD5+CD4+bcl-6+CD10+ immunophenotype. These results demonstrate the presence of a recurrent t(5;9)(q33;q22) in a subset of unspecified PTCL, which may represent a novel distinct subgroup of PTCL.

T(3;14)(p14.1;q32) involving IGH and FOXP1 is a novel recurrent chromosomal aberration in MALT lymphoma.

The three chromosomal translocations t(11;18)(q21;q21), t(14;18)(q32;q21), and t(1;14)(p22;q32) are associated with MALT lymphoma. In a case of MALT lymphoma of the thyroid, we observed t(3;14)(p14.1;q32) by cytogenetic analysis. Fluorescence in situ hybridization studies showed that the immunoglobulin heavy chain locus (IGH) was rearranged on chromosome 14. Long-distance inverse polymerase chain reaction identified FOXP1 as the partner gene on chromosome 3. To determine the frequency of the t(3;14)(p14.1;q32), two fluorescence in situ hybridization assays were established to screen 91 MALT lymphomas, all of which were negative for the above-mentioned three translocations, and eight splenic and six nodal marginal zone lymphomas. Overall, nine MALT lymphomas (10%) harbored t(3;14)(p14.1;q32) comprising tumors of the thyroid (three of six), ocular adnexa (four of 20), and skin (two of 20), whereas those of the stomach (n = 20), salivary gland (n = 20), and lung (n = 5) were negative as well as the splenic and nodal marginal zone lymphomas. Most t(3;14)(p14.1;q32) + MALT lymphomas harbored additional genetic abnormalities, such as trisomy 3. Further studies revealed that the three known translocations and t(3;14)(p14.1;q32) are mutually exclusive. Real-time quantitative reverse transcriptase polymerase chain reaction showed upregulation of FOXP1 in cases with t(3;14)(p14.1;q32) or trisomy 3. This study identifies FOXP1 as a new translocation partner of IGH in a site-dependent subset of MALT lymphomas.

High expression of lipoprotein lipase in poor risk B-cell chronic lymphocytic leukemia.

We investigated the pattern of lipoprotein lipase (LPL) expression in B-cell chronic lymphocytic leukemia (B-CLL) and assessed its prognostic relevance. Expression of LPL mRNA as well as protein was highly restricted to leukemic B cells. The intensity of intracellular immunoreactivity of LPL was higher in samples of patients with unmutated immunoglobulin heavy-chain variable region genes (IGV(H)) compared to those with mutated IGV(H) genes. LPL mRNA levels in peripheral blood mononuclear cells (PBMNC) from 104 CLL patients differed by 1.5 orders of magnitude between cases with mutated (N=51) or unmutated (N=53) IGV(H) (median: 1.33 vs 45.22 compared to normal PBMNC). LPL expression correlated strongly with IGV(H) mutational status (R=0.614; P<0.0001). High LPL expression predicted unmutated IGV(H) status with an odds ratio of 25.90 (P<0.0001) and discriminated between mutated and unmutated cases in 87 of 104 patients (84%). LPL expression was higher in patients with poor risk cytogenetics. High LPL expression was associated with a shorter treatment-free survival (median 40 vs 96 months, P=0.001) and a trend for a shorter median overall survival (105 months vs not reached). Our data establish LPL as a prognostic marker and suggest functional consequences of LPL overexpression in patients with B-CLL.

Templated nucleotide addition and immunoglobulin JH-gene utilization in t(11;14) junctions: implications for the mechanism of translocation and the origin of mantle cell lymphoma.

The t(11;14)(q13;q32) between the BCL-1 and immunoglobulin heavy chain gene (IgH) loci in mantle cell lymphoma (MCL) are believed to be mediated by the mechanism of V(D)J recombination similar to the t(14; 18) in follicular lymphoma (FL). We have recently shown that the t(14;18) event creates staggered double-strand breaks in the BCL-2 locus, and that the t(14;18) junctions contain templated nucleotide insertions (T-nucleotides; U. Jäger et al., Blood, 95: 3520-3529, 2000). Reasoning that the earlier (pregerminal center) B-cell origin of MCL might be reflected in a different molecular structure of the chromosomal breakpoints, we PCR-amplified diagnostic samples from 93 patients. Thirty-six samples (39%) were positive for the direct (BCL-1/J(H)) and 23 for both direct and reciprocal (D(H)/BCL-1) junctions. The breaks on chromosome 14 exhibited features of V(D)J-mediated recombination as shown by D(H) and J(H) coding end processing. However, duplications of BCL-1 sequences in 39% of the 23 patients indicate staggered double-strand breaks in the major translocation cluster region (MTC). This is incompatible with V(D)J recombination and indicates a different mechanism of cleavage. The use of J(H)6 in the junctions (39%) was similar to that in the immunoglobulin genes of normal B cells and B-CLL, but considerably less than in FL. Only 2 of 36 samples contained a BCL-1/DJ(H) rearrangement, which was indicative of a previous DJ(H) rearrangement. Most importantly, 19% of the BCL-1/IgH junctions with inserts of > or =5 nucleotides contained error-prone copies (T-nucleotides) of 8-12 nucleotides originating from the surrounding BCL-1 or IgH regions, a lower rate than in FL. No correlation was found between the addition of T-nucleotides and the rate of somatic mutation in the immunoglobulin genes. We conclude that the t(11;14) and t(14;18) use the same basic mechanism of translocation including V(D)J-mediated recombination, double-strand staggered breaks, and template-dependent, error-prone DNA-synthesis. However, the distinct differences in the utilization of J(H) regions suggest that the t(11;14) occurs predominantly during an attempted primary D(H)-J(H) rearrangement in early B cells, whereas the t(14;18) mostly occurs during secondary rearrangement. This is in agreement with the pregerminal center B-cell origin of MCL.

TNFalpha-mediated cell death is independent of cdc25A.

Tumor necrosis factor (TNFs) have been shown to be synthesized by ovarian carcinomas, and may therefore affect tumor cells in an autocrine manner. Therefore, we investigated the effects of recombinant TNFs on ovarian carcinoma cells N.1 and examined expression of the proto-oncogenes c-myc and cdc25A which are known to play a prominent role in apoptosis. TNFalpha elicited apoptosis in N.1 cells within 72 h which was shown by typical morphological changes, DNA fragmentation and signature type cleavage of poly(ADP-ribose) polymerase into a 89 kDa proteolytic peptide. TNFalpha-induced apoptosis was accompanied by constitutive c-Myc expression, although the mRNA level of phosphatase cdc25A was suppressed within 24 h of TNFalpha treatment and the protein level decreased after 48 h. Cdc25A tyrosine phosphatase is an activator of the cdk2-cyclin E complex which allows for cell cycle progression. As expected, we found TNFalpha-mediated Cdc25A down-regulation to inhibit Cdk2 activity. Cdc25A suppression was related to TNFalpha-induced apoptosis but not to a TNFalpha-induced G0 arrest because cyclin D1 expression was unaffected and the gene gas6 (growth arrest specific 6) was not induced. Arresting cells by treatment with genistein prevented TNFalpha-triggered apoptosis and inhibited c-myc expression. TNFalpha-induced apoptosis is not accompanied by cell cycle arrest which may be due to constitutive c-Myc expression, although Cdc25A and Cdk2 activity is also down-regulated. High c-Myc and low Cdc25A activity might present conflicting signals to the cell cycle machinery which are incompatible with cell survival.

Effective treatment of a peripheral T-cell lymphoma/lymphoepitheloid cell variant (Lennert's lymphoma) refractory to chemotherapy with the CD-52 antibody alemtuzumab.

Lymphoepitheloid cell lymphoma (Lennert's lymphoma) is a rare malignant disease usually affecting patients at advanced age. Although classified as a "low-grade" lymphoma in the past, the clinical course is highly unfavorable and currently available chemotherapeutic regimens have given disappointing results. We present the case of a 74-year-old male suffering from disseminated Lennert's lymphoma. The patient underwent standard treatment approaches including chemotherapy with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP); fludarabin and cyclophosphamide; and ifosfamide, carboplatin and etoposide (ICE). Due to progressive disease with all these regimens, chemotherapy was discontinued. As cells stained highly positive for CD52, immunotherapy with alemtuzumab (Campath-1H) was started using a standard dosing regime of 30 mg every third day. Although the patient received prophylactic anti-infective medication, leucocytopenia with reactivation of cytomegalovirus (CMV) infection was observed and the administration of alemtuzumab had to be stopped temporarily. Re-assessment of disease 5 weeks after the start of alemtuzumab disclosed a significant reduction of all thoracic and abdominal lesions, and therapy with alemtuzumab was continued after normalization of the number of CMV copies and is currently ongoing. Our observations indicate clinical activity of alemtuzumab in the treatment of Lennert's lymphoma, including even bulky nodal disease, particularly for patients who have failed conventional therapies.

Long-term alpha-interferon therapy in myelodysplastic syndromes.

The myelodysplastic syndrome (MDS) is characterized by a high probability of leukemic transformation and frequently lethal infections or bleeding episodes. Up to now, no generally accepted form of therapy has been established for MDS. Previous trials with alpha-interferon (IFN-alpha) have shown some beneficial effects. We studied the effects of long-term application of IFN-alpha at higher dosages in patients with "low-risk" MDS. Ten patients were included in the study; eight were treated for a period of 6-36 months. IFN-alpha was administered at a median dosage of 9, 6, 4 mU/week during the first, second, and third year, respectively. Response was determined by the status of peripheral blood and bone marrow. Prolonged exposure to IFN resulted in a response rate of 3/10 (30%). In an additional case, disease progression was retarded during the third year of therapy. The incidences of infections and bleeding events subsided notably. After the withdrawal of IFN, hematological and clinical parameters rapidly deteriorated in some patients. The observed improvement of the patients' susceptibility to infections possibly prolongs their survival and seems to justify further trials on IFN treatment in patients with MDS.

Alternative end-joining in follicular lymphomas' t(14;18) translocation.

T(14;18) chromosomal translocation is assumed to result from illegitimate rearrangement between the BCL2 proto-oncogene and the IGH locus during the D(H) to J(H) joining phase of V(D)J recombination in early B cells. Analysis of the breakpoint junctions suggests that translocation derives from the fusion between normal V(D)J recombination intermediates at the IGH locus and non-V(D)J-mediated broken-ends at the BCL2 locus. So far, BCL2 broken-ends have only been observed fused to coding-ends, raising questions concerning the molecular constraints of the illegitimate joining process. Using a combination of genome walking and long-range PCR assays, we describe in this report that in 4.5% (2/44) of the t(14;18), one of the BCL2 broken-ends is fused to a signal-end. The formation of these J(H)RSS/BCL2 junctions provides direct evidence that BCL2 broken-ends are capable of joining to both products of V(D)J recombination, suggesting their presence in the RAG-mediated post-cleavage complex. In addition, junctions generated by this alternative end-joining do not involve deletion of the chromosome 14 intervening sequences generally lost in the standard translocation, providing a unique opportunity to investigate the rearrangement status of this region in the translocated IGH allele. In both cases, a DJ(H) rearrangement could be detected 5' of the J(H)-RSS/BCL2 junction. These findings, together with the previously reported bias towards the most external D(H) and J(H) segments in standard breakpoints, strongly suggest that t(14;18) preferentially occurs during an attempted secondary D(H) to J(H) rearrangement. This unusual and restricted window of differentiation opens intriguing questions concerning the etiology of the translocation.

Prognostic significance of molecular staging by PCR-amplification of immunoglobulin gene rearrangements in diffuse large B-cell lymphoma (DLBCL).

The prognostic value of the detection of peripheral blood (PB) and/or bone marrow (BM) involvement by polymerase chain reaction (PCR) amplification of rearranged immunoglobulin heavy chain (IgH) and immunoglobulin kappa light chain (Igkappa) genes was evaluated in 155 patients with diffuse large B-cell lymphomas (DLBCL). Immunoglobulin gene rearrangements (IgR) were detected in 35/155 (23%) patients. The presence of IgR in PB/BM was related to clinical stage (CS I-III vs CS IV; P<0.001), histopathological detection of BM involvement (P<0.001), and the International Prognostic Index (P<0.001). IgR-positive cases had a significantly lower complete remission (CR) rate (18/35, 51%) than IgR-negative patients (85/120, 71%; P=0.042), and a significantly poorer overall survival (OAS) at 5 years (25 vs 66%; P<0.001). There was a significant difference in the estimated OAS at 5 years between patients with negative BM histology and negative PCR results (66%), patients with negative BM histology but positive IgR (37%), and patients with positive BM histology (12%). Our results indicate that molecular methods improve the accuracy of staging in patients with DLBCL and define a group of patients with normal bone marrow histology who have a significantly poorer OAS due to molecular detection of PB/BM involvement.

Karyotype and prognosis in non-Hodgkin lymphoma.

In malignant non-Hodgkin lymphomas (NHL), cytogenetic analysis may provide prognostic information including prediction of histologic evolution and responsiveness to therapy. In this study, we correlate clinical data and chromosomal aberrations in 70 adult patients with newly diagnosed NHL followed for a median of 20 months. Clonal aberrations were detected in 68/70 patients (97%). Besides t(2;5)(p23;q35), observed exclusively in three patients with anaplastic large cell lymphoma, Ki-1 positive, none of the characteristic aberrations observed was specific for a given histological subtype. Aberrations of chromosome 7 (n = 21) occurred in all histological subtypes together with aberrations of chromosome 3 and of the short arm of chromosome 17. They were clinically associated with a high serum lactate dehydrogenase level (LDH) and a trend to short survival. Anomalies of the long arm of chromosome 13 (n = 10) were found in patients with high grade B-cell lymphomas and bulky disease. In t(14;18)(q32;q21) bearing lymphomas (n = 27), distinct patterns of additional aberrations were observed in low grade and high grade lymphomas: trisomy 3 and trisomy 18 occurred concomitantly in high grade lymphomas (n = 6, p < 0.001) as well as aberrations of 1q, 5q, 6q and +der (18)(q21). In conclusion, cytogenetic analysis provides information about the complexity of genetic changes in NHL. These changes act not only as indicators of disease activity, but influence clinical outcome as demonstrated by their stringent correlation to the International Index and might reveal more general rules of tumor growth and spreading.

Frequent allelic imbalance but infrequent microsatellite instability in gastric lymphoma.

Specific defects in DNA repair pathways are reflected by DNA microsatellite instability (MSI) and play an important role in carcinogenesis. Reported frequencies in gastric non-Hodgkin's lymphomas (NHL) vary from 14% to as high as 90%. Another form of genetic instability in tumours is allelic imbalance (AI) due to loss or gain of genetic material at a specific chromosomal region. This might point to the presence of a tumour suppressor gene or oncogene. We examined both MSI and AI in 26 gastric lymphomas (10 low-grade and 13 high-grade MALT lymphomas and three cases lacking MALT features and categorised as diffuse large B cell lymphoma (DLCL)). Tumour components and normal cells (epithelium, muscle) were microdissected from paraffin-embedded resection samples. Contrary to other studies we did not observe frequent MSI when investigating 18 different loci distributed over 12 chromosomes. Microsatellite instability of a single locus was found in 1/10 (10%) low-grade MALT lymphomas and 2/13 (15%) high-grade MALT lymphomas. These data indicate that DNA mismatch repair genes do not play a role in the pathogenesis of these lymphomas. Allelic imbalance was detected in 60% (6/10) of low-grade MALT lymphomas, in 62% (8/13) of high-grade MALT lymphoma and in 67% (2/3) of DLCL. In high-grade lymphomas more loci showed AI (one to seven loci, with a mean of 2.5 loci per case) than in the low-grade lymphomas (one to two loci, with a mean of 1.3 loci per case), possibly reflecting an increased genomic instability.

Diffuse large B-cell lymphomas with plasmablastic/plasmacytoid features are associated with TP53 deletions and poor clinical outcome.

To define reproducible criteria for subgroups of diffuse large B-cell lymphomas (DLBCL), including lymphomas with plasmablastic/plasmacytoid features (PB/PC-Fs), we investigated 66 DLBCL; the samples were categorized as either centroblastic (CB), immunoblastic (IB) or PB/PC-F applying standardized morphologic criteria. Blinded specimens were reviewed by three independent pathologists. The final consensus classification included 44 CB (67%), seven IB (10%) and 15 PB/PC-F (23%). The interobserver agreement between two centers (Vienna, Würzburg) was 93.5%. Most PB/PC-F were CD20+, cIgM+, MUM-1+, CD138+/-, bcl-6-, corresponding to an activated B-cell phenotype. Immunoglobulin-V(H) gene mutation analysis was consistent with a germinal or postgerminal center-cell origin. By fluorescence in situ hybridization analysis, 11/13 (85%) PB/PC-F had a monoallelic TP53 deletion. The pretreatment characteristics of patients with PB/PC-F included a tendency for more B symptoms, extranodal disease and a higher IPI. Importantly, PB/PC-F were resistant to standard chemotherapy (complete remission rate 47%, relapse rate 71%) and even autologous stem-cell transplantation. The median overall survival (OS) (14 months, P<0.002) and disease-free survival (6 months, P=0.02) were significantly shorter compared to patients with CB and IB. The OS difference was pronounced within the low and low-intermediate IPI risk group (P<0.001). Our data indicate a strong association of plasmablastic/plasmacytoid morphology with TP53 deletions, poor response to chemotherapy and short survival.