Motive and Opportunity: MYC rearrangements in high-grade B-cell lymphoma with MYC and BCL2 rearrangements-an LLMPP study

Rearrangements that place the oncogenes MYC, BCL2, or BCL6 adjacent to superenhancers are common in mature B-cell lymphomas. Lymphomas with diffuse large B-cell lymphoma (DLBCL) or high-grade morphology with both MYC and BCL2 rearrangements are classified as high-grade B-cell lymphoma with MYC and BCL2 rearrangements ("double hit": HGBCL-DH-BCL2) and are associated with aggressive disease and poor outcomes. Although it is established that MYC rearrangements involving immunoglobulin (IG) loci are associated with inferior outcomes relative to those involving other non-IG superenhancers, the frequency of, and mechanisms driving, IG vs non-IG MYC rearrangements have not been elucidated. Here we used custom targeted capture and/or whole genome sequencing to characterize oncogene rearrangements across 883 mature B-cell lymphomas including Burkitt lymphoma, follicular lymphoma, DLBCL, and HGBCL-DH-BCL2 tumors. We demonstrate that, while BCL2 rearrangement topology is consistent across entities, HGBCL-DH-BCL2 have distinct MYC rearrangement architecture relative to tumors with single MYC rearrangements or with both MYC and BCL6 rearrangements (HGBCL-DH-BCL6), including both a higher frequency of non-IG rearrangements and different architecture of MYC::IGH rearrangements. The distinct MYC rearrangement patterns in HGBCL-DH-BCL2 occur on the background of high levels of somatic hypermutation across MYC partner loci in HGBCL-DH-BCL2, creating more opportunity to form these rearrangements. Furthermore, because one IGH allele is already disrupted by the existing BCL2 rearrangement, the MYC rearrangement architecture in HGBCL-DH-BCL2 likely reflects selective pressure to preserve both BCL2 and B cell receptor expression. These data provide new mechanistic explanations for the distinct patterns of MYC rearrangements observed across different lymphoma entities.

A 17-year old patient with DOCK8 deficiency, severe oral HSV-1 and aggressive periodontitis - a case of virally induced periodontitis?

We present a 17-year old girl with DOCK-8 deficiency, severe untreated oral HSV-1 infection and associated aggressive periodontitis. DOCK-8 deficiency is a primary immunodeficiency, caused by biallelicloss-of-function mutations in the DOCK8 gene, often leading to severe viral and fungal mucocutaneous infections. Nevertheless, to date DOCK8 has not been associated with severe periodontitis and inflammatory bone loss around teeth. Understanding whether DOCK8 deficiency or severe HSV-1 infection underlies susceptibility to periodontitis is central to this case and may provide insights into susceptibility factors for periodontitis in the general population. Our clinical and microbiological data suggest that severe HSV-1 infection is the driver of periodontal inflammation in this case.

Mutations in PIK3CD can cause hyper IgM syndrome (HIGM) associated with increased cancer susceptibility

Autosomal dominant gain of function mutations in the gene encoding PI3K p110δ were recently associated with a novel combined immune deficiency characterized by recurrent sinopulmonary infections, CD4 lymphopenia, reduced class-switched memory B cells, lymphadenopathy, CMV and/or EBV viremia and EBV-related lymphoma. A subset of affected patients also had elevated serum IgM. Here we describe three patients in two families who were diagnosed with HIGM at a young age and were recently found to carry heterozygous mutations in PIK3CD. These patients had an abnormal circulating B cell distribution featuring a preponderance of early transitional (T1) B cells and plasmablasts. When stimulated in vitro, PIK3CD mutated B cells were able to secrete class-switched immunoglobulins. This finding implies that the patients' elevated serum IgM levels were unlikely a product of an intrinsic B cell functional inability to class switch. All three patients developed malignant lymphoproliferative syndromes that were not associated with EBV. Thus, we identified a novel subset of patients with PIK3CD mutations associated with HIGM, despite indications of preserved in vitro B cell class switch recombination, as well as susceptibility to non-EBV-associated malignancies.

Phase I/II study of a hybrid schedule of flavopiridol in relapsed/refractory mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL)

8563

Background: Continuous infusion and bolus schedules of flavopiridol in MCL have yielded disappointing results. However, a pharmacologically derived hybrid schedule of administration is effective in refractory, genetically high-risk CLL, though life-threatening tumor lysis syndrome (TLS) may occur in patients with very high lymphocyte counts. Because flavopiridol decreases cyclin D1 and mcl-1 and induces apoptosis in MCL cells, is significantly toxic for cell lines derived from the activated B-cell-like type of DLBCL (OCI-Ly3) and down-regulates NF-kappa B, we investigated the hybrid schedule in MCL and DLBCL. Methods: Flavopiridol was administered as a 30-minute bolus (mg/m2) followed by a 4-hour continuous infusion (mg/m2), weekly for 4 doses every 6 weeks. Separate escalation rules applied to cycle 1 week 1 (C1W1) and all other weeks of treatment. Dose levels on C1W1 were DL1: 25/25 (4 pts); DL2: 30/30 (10 pts) and DL3: 30/50 (6 pts). Dose escalation on subsequent weeks was not possible due to toxicity and all pts received 30/50. All patients received TLS prophylaxis. Paired biopsy samples obtained before and after the first dose were analyzed for cdk targets. Results: Patient (n=20) characteristics: median age: 59 (r 24–80); male 15 (75%); median prior regimens 2 (r 1–6). 10 had MCL and 10 had DLBCL. Responses were PR in 2 (1 MCL; 1 DLBCL) pts (10%); SD in 5 (25%); and PD in 13 (65%). DLTs were TLS and severe vomiting/diarrhea in 2 pts at DL3. The MTD and phase II dose has not yet been defined. Other toxicities were grade 4 ANC (10 pts) requiring prophylactic G-CSF, TLS (1 pt) and bowel perforation (1 pt). Decreased Rb staining at the S807/811 phospho-site was noted in 8 of 9 paired samples analyzed (r 20–75%; p = 0.027) and at the S780 site in 7 of 8 paired samples (r 38–91%; p = 0.00016), suggestive of G1 cdk inhibition. In 1 sample in which p53 was detected, there was an increase post-treatment, suggestive of cdk9 inhibition. Conclusions: The hybrid schedule of flavopiridol has modest activity in relapsed MCL and DLBCL. TLS occurred infrequently and was reversible. DLTs were TLS and gastrointestinal toxicity. Accrual continues. Analysis of cell cycle and transcriptional cdk targets is ongoing.

No significant financial relationships to disclose.

Dermatofibrosarcoma protuberans (DFSP) in six patients with ADA-SCID

10570

Background: DFSP is a rare malignant skin tumor associated with a characteristic chromosomal translocation (t(17;22)(q22;q13)), resulting in the COL1A1-PDGFB fusion gene. We originally diagnosed DFSP in two patients affected with a rare form of severe combined immunodeficiency due to adenosine deaminase deficiency (ADA-SCID). The association of these two rare conditions has been described in two other cases, which prompted us to screen for DFSP systematically in patients with ADA-SCID. Methods: Eight ADA-SCID patients were evaluated with complete dermatological exam and skin biopsy. Molecular analysis (FISH and/or RT-PCR) and karyotype were performed when possible. Results: Six patients (age 2, 2, 5, 9, 12 and 22 years) were found to have DFSP. Five patients had between 4 and 12 multicentric lesions over the trunk and extremities. One patient had a single lesion. Most lesions appeared as 2–15 mm tan atrophic plaques. Nodular lesions were present in 3 patients. All lesions showed a spindle cell proliferation of the dermis, extending into the subcutaneous fat. A storiform pattern was only noticed in one adult patient. In all cases, CD34 expression was diffusely positive and FXIIIa was negative. Karyotype showed t(17;22)(q22;q13) in the 2 patients in whom it was performed. FISH was positive for COL1A1-PDGFB in 2 of 4 patients studied. RT-PCR showed the COL1A1-PDGFB fusion transcript in one case in which FISH was inconclusive.FISH and RT-PCR analyses are being conducted in 2 and 5 remaining cases, respectively. Conclusions: We describe a previously unrecognized association between multicentric DFSP and ADA-SCID. Multicentricity of DFSP to this extent has not previously been reported . We hypothesize that t(17;22)(q22;q13) may arise due to the known DNA repair defect in ADA-SCID and that the known dermal overexpression of PDGFB in this condition may favor the development of fibrotic tumors, as opposed to other skin cancers. Our observations can provide further insight into the pathogenesis of DFSP and should facilitate early diagnosis of DFSP in ADA-SCID.

No significant financial relationships to disclose.

Clinical evidence of a graft-versus-lymphoma effect against relapsed diffuse large B-cell lymphoma after allogeneic hematopoietic stem-cell transplantation

BACKGROUND

A graft-versus-lymphoma effect against diffuse large B-cell lymphoma (DLBCL) is inferred by sustained relapse-free survival after allogeneic stem-cell transplantation; however, there are limited data on a direct graft-versus-lymphoma effect against DLBCL following immunotherapeutic intervention by either withdrawal of immunosuppression or donor lymphocyte infusion (DLI).

MATERIALS AND METHODS

An analysis was carried out to determine whether a direct graft-versus-lymphoma effect exists against DLBCL. The analysis was restricted to patients with DLBCL, who were either not in complete remission at day +100 after allogeneic stem-cell transplantation or subsequently relapsed beyond this time point.

RESULTS

Fifteen patients were identified as either not in complete remission (n = 13) at their day +100 evaluation or subsequently relapsed (n = 2) and were assessed for subsequent responses after withdrawal of immunosuppression or DLI. Eleven patients were treated with either withdrawal of immunosuppression (n = 10) or a DLI (n = 1) alone; four patients received chemotherapy with DLI to reduce tumor bulk. Nine (60%) patients subsequently responded (complete = 8, partial = 1). Six responses occurred after withdrawal of immunosuppression alone. Six patients are alive (range 42-83+ months) in complete remission without further treatment.

CONCLUSION

The demonstration of sustained complete remission following immunotherapeutic intervention provides direct evidence of a graft-versus-lymphoma effect against DLBCL.

Efficacy and toxicity of dose-adjusted EPOCH-rituximab in adults with newly diagnosed Burkitt lymphoma

8035

Background: Burkitt Lymphoma (BL) is a rare and highly aggressive lymphoma, characterized by a high tumor proliferation rate. While the standard therapy of BL is highly effective, it involves intensive, multi-agent chemotherapy that is associated with considerable treatment-related toxicity and mortality, especially in older patients. We hypothesized that the regimen DA-EPOCH may be effective in BL, based on the observation that it overcomes the adverse effect of high proliferation in diffuse large B-cell lymphoma. Methods: We investigated DA-EPOCH-rituximab (R) in untreated BL in an attempt to maintain the high cure rates of standard therapy with minimal treatment related toxicity. Eligible patients had a diagnosis of untreated BL and could be HIV negative or positive with HIV negative patients (n=13) receiving 6 cycles of DA-EPOCH-R as previously described (Blood 99: 2685, 2002) and HIV positive (n=6) patients receiving 3–6 cycles of DA- EPOCH-R for 1 cycle beyond CR for a minimum of 3 cycles. All patients received intrathecal methotrexate prophylaxis and outpatient therapy where possible. Results: The characteristics of 19 enrolled patients are: median age (range) 29 (18–66) and ECOG PS 1(1–3); stage III/IV 10 (53%); LDH > N 11 (61%); male sex 15 (79%); extranodal sites 13 (68%) and ileocecal disease 13 (68%). No patients so far had CNS involvement at diagnosis. Response is CR/CRu in 100% of patients with one patient receiving consolidative radiotherapy to a site of residual disease. OS and PFS are both 100% and EFS 93.3% at a median potential follow-up time of 29 months. Toxicities were fever/neutropenia in 16%, grade 4 neutropenia in 47% and grade 3/4 thrombocytopenia in 22% of cycles. There was one case of tumor lysis syndrome and no treatment related deaths. Conclusions: DA-EPOCH-R is highly effective in BL. It appears to be associated with much lower toxicity compared to standard high-dose regimens and may significantly advance the therapeutic index of BL treatment. Accrual continues.

No significant financial relationships to disclose.

Treatment and biology of lymphomatoid granulomatosis

8029

Background: LYG is a rare angiocentric-destructive process with EBV+ B-cells and reactive T-cells. LYG is graded with grades I-II showing rare-moderate large EBV+ B-cells (usually polyclonal or oligoclonal) and grade III showing numerous large EBV+ B-cells (usually monoclonal), likely reflecting progressive transformation. Historically, steroids and/or chemotherapy have a 14 mos median survival. Methods: We are investigating Interferon-a (I-a) for grade I/II and dose-adjusted EPOCH ±Rituximab (R) for grade III LYG. Results: Characteristics of 53 pts are: male sex 68%; median age (range) 46 (17–67) and median ECOG P.S. 1 (0–3). Disease sites include lung 98%, CNS 38%, kidney 15%, skin 17%, liver 19% and nodes 4%. On study LYG grades are I-30%, II-26% and III-44%. Prior treatment was none-28%, chemotherapy± R-34%, and steroids alone-40% of pts. For grades I/II, I-a is begun at 7.5 million IUs TIW and escalated as tolerated until disease regression and continued 1 yr after CR. Of 31 patients treated with I-a, PFS is 62% at the median f/u of 5.3 yrs. Of 25 evaluable pts (3 NE; 3 TE), 60% had sustained CR for a median of 60 mos (4–175). In 9 pts who progressed on I-a, grade III was found in 5. Thus, in 20 pts with only grade I/II, 75% had sustained CR with I-a. In 11 evaluable pts with CNS disease, 81% achieved remission with I-a alone. The median time to remission is 9 mos (3–40) and median I-a dose is 20 MIU (7–40). Among 24 pts receiving DA-EPOCH±R, PFS is 40% at the median f/u of 28 mos. Of 21 evaluable pts (2 NE, 1 TE), 66% achieved CR. OS of all 53 pts is 68% at the median f/u of 4 yrs. Median EBV viral loads in 29 pts at study entry were 18 copies/10e6 genome equivalents (0–22727) (normal<200). Lymphocyte subsets in 30 pts showed a median CD4–428 (24–2322) and CD8–165 cells/mm3 (42–1316). In 12 pts in CR and with serial values, the mean CD8 cells (131 ± 44) (p2= 0.013) but not CD4 cells (65 ± 75) increased with treatment. Conclusions: High dose I-a produces sustained remissions in grade I/II LYG and is effective in CNS LYG. DA-EPOCH±R can produce durable CRs in grade III LYG. We hypothesize LYG emerges in a compromised immune milieu and undergoes progressive transformation if not effectively treated. Historical results suggest steroids may allow transformation by compromising immune function.

No significant financial relationships to disclose.

Reduced-intensity allogeneic stem cell transplantation for diffuse large B-cell lymphoma: Clinical evidence of a graft-versus-lymphoma effect

6546

Background: Despite being the most common non-Hodgkin’s lymphoma, there have been no specific reports on the use of reduced-intensity (RI) allogeneic stem cell transplantation (alloSCT) to treat patients (pts) with diffuse large B-cell lymphomas (DBCL). This may be due to a lack of definitive evidence for a therapeutic graft-versus-lymphoma (GVL) effect against DLBC. We undertook a retrospective analysis to assess clinical outcomes and evidence of a GVL effect in DLBC pts undergoing RI alloSCT. Methods: The analysis was limited to 18 pts with primary refractory (n = 6) or relapsed (n = 12) DLBC. The median age was 43 years (range: 31–61); median number of previous treatments was 3 (range: 2–9). Nine (50%) pts had undergone autologous transplantation. Three (16%) pts were determined to have chemo-sensitive disease to last treatment prior to RI alloSCT. All pts received a RI conditioning regimen consisting of fludarabine (30 mg/m2/d × 4d) and cyclophosphamide (1200 mg/m2/d × 4d) followed by a T-cell replete allograft from HLA-matched siblings. Results: Median potential follow-up from transplant is 43 months. Seven (39%) pts developed grade II-IV acute GVHD. Response at day +100 post-transplant was as follows: complete response (CR/CRu) = 5; partial response = 5; progressive disease = 8. Nine of 17 (53%) evaluable pts developed chronic GVHD. Median progression-free survival (PFS) was 4.8 months; however, PFS after 9 months post-transplant was 31% with 5 pts in continuous CR/CRu > 12 months post-transplant. Among 14 pts who were not in CR/CRu (n = 12) or progressed after achieving a CR/CRu (n = 2) at day +100 post-transplant, 8 (57%) subsequently achieved a CR/CRu after removal of immune suppression and/or donor lymphocyte infusion (DLI) ± chemotherapy. Seven of these 8 pts remain in continuous (median = 34 months; range: 6–55+) CR/CRu without further treatment. Median survival for all 18 pts was 19 months with survival probability of 40% plateauing at 25 months post-transplant. Conclusions: The clinical observations of sustained CR/CRu after withdrawal of immune suppression and DLI suggest that a GVL effect exists against DLBC. RI alloSCT should be considered as a treatment option for pts with primary refractory and relapsed DLBC.

No significant financial relationships to disclose.

A phase I study of antitumor vaccination using tumor cells genetically modified to express alpha(1,3)galactosyltransferase (αGT) in patients with refractory or recurrent non-small cell lung cancer (NSCLC)

12503

Background: Despite new treatments, lung cancer remains the leading cause of cancer death. We examined the safety and activity of antitumor vaccination using genetically altered human non-small cell lung cancer cells (HAL; HyperAcute Lung Cancer Vaccine) engineered to express xenotransplantation antigens through retroviral transfer of the murine αGT gene in patients (Pts.) with NSCLC. Methods: A single institution Phase I trial. Eligibility: Stage IV, recurrent or progressive NSCLC, Age ≥18, ECOG PS ≤2, prior chemotherapies ≤2, AGC ≥1,500/μL, Plts. ≥100,000/μL, adequate hepatic/renal function and informed consent. Cohorts of Pts. received intrademal injections of 3 × 106, 10 × 106, 30 × 106, or 100 × 106 HAL vaccine cells every 4-weeks × 4, or 500 × 106 HAL cells followed by 300 × 106 HAL cells every 2-weeks × 7. Toxicity was assessed using CTCv3.0 and response by RECIST criteria. Immunological responses included anti-αGal antibody titers, interferon-γ ELISPOT and vaccine site skin biopsies. Results: Seventeen Pts., 9 men and 8 women, median age 57 years (range, 34–85), median number of prior chemotherapies 1 (range, 1–2) were vaccinated. There were no Grade 3/4 adverse events attributable to the study vaccine. Adverse events (≤grade 2) attributable to vaccination include injection site urticaria, pain/discomfort, local skin reaction, fatigue, herpes zoster, arthralgias/myalgias and hypertension. Six Pts. had stable disease ≥16 weeks duration (range, 16–85+ weeks), 9 Pts. progressed and 2 Pts. were not evaluable for response. Skin biopsies 48-hrs after vaccination demonstrated vaccine cells in the dermis with acute infiltration of lymphocytes, granulocytes and eosinophils. Serum anti-αGal titers increased 10–14 fold with vaccination. Conclusions: Xenogeneic antitumor vaccination with genetically altered allogeneic human lung cancer cells expressing αGT is safe and feasible. A phase II trial is planned.

No significant financial relationships to disclose.

Cutaneous lymphomatoid granulomatosis: correlation of clinical and biologic features

Lymphomatoid granulomatosis (LYG) is a rare angiocentric and angiodestructive Epstein-Barr virus-associated B-cell lymphoproliferative disorder (EBV-BLPD), varying widely from an indolent process to an aggressive large cell lymphoma. The skin is the extrapulmonary organ most commonly involved in LYG. We studied 32 skin lesions from 20 patients with known pulmonary LYG, using immunohistochemistry, in situ hybridization for EBV, and polymerase chain reaction for the presence of antigen receptor gene rearrangements (IgH and TCR) to better define both the clinicopathologic spectrum and pathogenesis of the cutaneous lesions. We describe two distinct patterns of cutaneous involvement. Multiple erythematous dermal papules and/or subcutaneous nodules, with or without ulceration, were present in 17 patients (85%). These lesions demonstrate a marked angiocentric lymphohistiocytic infiltrate, composed predominantly of CD4-positive T-cells, with a high propensity for involving the subcutaneous tissues, and exhibiting angiodestruction, necrosis, and cytologic atypia. EBV-positive B-cells were detected in the nodules from five patients; clonal immunoglobulin heavy chain gene (IgH) rearrangements were detected by polymerase chain reaction in two patients. Multiple indurated, erythematous to white plaques were present in three patients (15%). The plaque lesions were negative for EBV and clonal IgH gene rearrangements in all cases studied. The clinical course of overall disease was variable, ranging from spontaneous regression without treatment (1 of 13; 7%), resolution with chemo/immunomodulatory therapy (8 of 13; 62%), and progression (4 of 13; 31%). The clinical and histopathologic features of cutaneous LYG are extremely diverse. However, the majority (85%) of the cutaneous lesions mirrors to some extent LYG in the lung, although EBV+ cells are less frequently identified. This subset of cases shows the histopathologic triad of angiodestruction with associated necrosis, panniculitis, and in some cases atypical lymphoid cells. The commonality of the histologic features in this group suggests a common pathophysiologic basis, possibly mediated by cytokines and chemokines induced by EBV. A small percentage of the lesions (15%) presented as indurated and atrophic plaques, and EBV was not identified in the small number of cases studied. The relationship of the plaque-like lesions to LYG remains uncertain. Whereas some cases of LYG regress spontaneously, most require therapy.

ANX7, a candidate tumor suppressor gene for prostate cancer

The ANX7 gene is located on human chromosome 10q21, a site long hypothesized to harbor a tumor suppressor gene(s) (TSG) associated with prostate and other cancers. To test whether ANX7 might be a candidate TSG, we examined the ANX7-dependent suppression of human tumor cell growth, stage-specific ANX7 expression in 301 prostate specimens on a prostate tissue microarray, and loss of heterozygosity (LOH) of microsatellite markers at or near the ANX7 locus. Here we report that human tumor cell proliferation and colony formation are markedly reduced when the wild-type ANX7 gene is transfected into two prostate tumor cell lines, LNCaP and DU145. Consistently, analysis of ANX7 protein expression in human prostate tumor microarrays reveals a significantly higher rate of loss of ANX7 expression in metastatic and local recurrences of hormone refractory prostate cancer as compared with primary tumors (P = 0.0001). Using four microsatellite markers at or near the ANX7 locus, and laser capture microdissected tumor cells, 35% of the 20 primary prostate tumors show LOH. The microsatellite marker closest to the ANX7 locus showed the highest rate of LOH, including one homozygous deletion. We conclude that the ANX7 gene exhibits many biological and genetic properties expected of a TSG and may play a role in prostate cancer progression.

Gene-expression profiles in hereditary breast cancer

BACKGROUND

Many cases of hereditary breast cancer are due to mutations in either the BRCA1 or the BRCA2 gene. The histopathological changes in these cancers are often characteristic of the mutant gene. We hypothesized that the genes expressed by these two types of tumors are also distinctive, perhaps allowing us to identify cases of hereditary breast cancer on the basis of gene-expression profiles.

METHODS

RNA from samples of primary tumor from seven carriers of the BRCA1 mutation, seven carriers of the BRCA2 mutation, and seven patients with sporadic cases of breast cancer was compared with a microarray of 6512 complementary DNA clones of 5361 genes. Statistical analyses were used to identify a set of genes that could distinguish the BRCA1 genotype from the BRCA2 genotype.

RESULTS

Permutation analysis of multivariate classification functions established that the gene-expression profiles of tumors with BRCA1 mutations, tumors with BRCA2 mutations, and sporadic tumors differed significantly from each other. An analysis of variance between the levels of gene expression and the genotype of the samples identified 176 genes that were differentially expressed in tumors with BRCA1 mutations and tumors with BRCA2 mutations. Given the known properties of some of the genes in this panel, our findings indicate that there are functional differences between breast tumors with BRCA1 mutations and those with BRCA2 mutations.

CONCLUSIONS

Significantly different groups of genes are expressed by breast cancers with BRCA1 mutations and breast cancers with BRCA2 mutations. Our results suggest that a heritable mutation influences the gene-expression profile of the cancer.

Detection of differentially expressed genes in lymphomas using cDNA arrays: identification of clusterin as a new diagnostic marker for anaplastic large-cell lymphomas

This study reports the first use of gene array technology for the identification of a tumor-specific marker in lymphoid neoplasms. The differential gene expression of 31 hematopoietic cell lines, representing most major lymphoma subgroups of B- and T-cell origin, was assessed by hybridizing labeled complementary DNA to Atlas human expression arrays containing 588 genes. Genes known to be specific for B, T, or myelomonocytic lineages were appropriately identified in the arrays, validating the general utility of this approach. One gene, clusterin, not previously known to be expressed in lymphoid neoplasms, was specifically found in all 4 anaplastic large-cell lymphoma (ALCL) cell lines, but not in any of the 27 remaining tumor lines. Using a monoclonal antibody against clusterin, its differential expression was confirmed by Western blotting and immunohistochemistry. A total of 198 primary lymphomas (representing most major lymphoma subtypes), including 36 cases of systemic ALCL, were surveyed for clusterin expression by immunohistochemistry and Western blotting. All of the 36 ALCL cases marked for clusterin, with most cases showing moderate to strong staining in the majority of neoplastic cells. Clusterin expression was not related to expression of anaplastic lymphoma kinase-1. With 2 exceptions, none of the remaining 162 non-ALCL cases marked with the clusterin antibody, including Hodgkin disease and primary cutaneous ALCL. In reactive lymphoid tissues, only follicular dendritic cells and fibroblastic reticular cells exhibited staining. Clusterin is a highly conserved glycoprotein implicated in intercellular and cell matrix interactions, regulation of the complement system, lipid transport, stress responses, and apoptosis. Although its function in ALCL is unknown, the unique expression of clusterin within this category of lymphoma provides an additional marker for the diagnosis of ALCL. This study illustrates the enormous potential of gene array technologies for diagnostic marker discovery. (Blood. 2000;96:398-404)

Analysis of expressed immunoglobulin heavy chain genes in familial B-CLL

In this study, we wished to determine whether familial chronic lymphocytic leukemia of B-cell phenotype (CLL) shares with sporadic B-CLL the same immunoglobulin (Ig) heavy chain variable region (VH) gene usage and occurrence of somatic mutation, to gain insight into the pathogenetic relatedness of these epidemiologically distinct forms of CLL. We therefore analyzed the expressed Ig heavy chain genes in 23 cases (11 families) of familial CLL, and compared these results with data previously reported for sporadic CLL. In addition, we assessed the relationship of the occurrence of somatic mutation to several clinical and phenotypic features. The distribution of V genes among these cases was similar to that observed in sporadic CLL: VH3 > VH1 > VH4. Thirteen of the 23 cases (57%) showed germ line VH gene sequences, whereas somatic mutations were detected in 10 cases (43%). The average mutation frequency of these latter 10 cases of was 6.7% (ranging from 1.7% to 8.8%), and evidence of antigen selection was noted in 6. Intraclonal variation, followed by clonal evolution and the appearance of a second clone over a 20-year period was observed in 1 case, suggesting that mutations can continue to accumulate after neoplastic transformation. The presence of somatic mutations correlated with age at presentation, low white blood cell (WBC) count, and low fluorescence intensity of surface CD5, and the potential significance of these relationships is discussed. Our data indicate that familial and sporadic B-CLL display a similar pattern of immunoglobulin gene usage and frequency of somatic mutation, and are consistent with a common ontogeny and immunogenetic origin for these 2 epidemiologically distinct forms of CLL. (Blood. 2000;95:1413-1419)

Secondary chromosome changes in mantle cell lymphoma

BACKGROUND AND OBJECTIVE

Mantle cell lymphomas (MCLs) comprise a rare but distinct clinicopathological entity usually associated with t(11;14). This translocation is regarded as a primary event, but it has been suggested that other as yet unidentified genetic alterations are required for development and progression of MCL.

DESIGN AND METHODS

In order to identify recurrent secondary changes that might point towards specific chromosomal regions contributing to the pathogenesis of MCL we studied 43 MCL cases in which clonal chromosomal abnormalities have been found during cytogenetic analysis.

RESULTS

In this series 83% of cases were characterized by t(11;14) and in the majority of them the t(11;14) was associated with multiple other chromosomal aberrations. Recurrent secondary changes were found in which imbalances of genetic material prevailed, losses being more common than gains. The former involved thirteen chromosomes, especially 13, 6q, 9q, 11q, 8/8p, 10/10p, and 14, whereas recurrent gains affected 3/3q. Non-randomly occurring breakpoints were relatively infrequent. The identified anomalies were also involved in aberrations observed in the group of MCL not associated with t(11;14). Some of them are shared with other B-cell proliferations.

INTERPRETATION AND CONCLUSIONS

The data presented here indicate that MCL is characterized by consistently occurring secondary chromosome changes. Their significance for the development and/or progression of MCL needs to be elucidated and confirmed by further investigations.

Primary diffuse large B cell lymphoma of the stomach: analysis of somatic mutations in the rearranged immunoglobulin heavy chain variable genes indicates antigen selection

Gastric low grade MALT lymphomas show a pattern of somatic mutations in their rearranged immunoglobulin genes, indicative of antigen selection. This provides evidence for antigen stimulation in the lymphomagenesis. Gastric diffuse large B cell lymphomas develop secondary to low grade MALT lymphoma or de novo. To study whether antigen-selection is also a feature of primary diffuse large B cell lymphomas, we analysed somatic mutations in the rearranged immunoglobulin heavy chain (IgH) variable genes (VH). The rearranged VH genes of six cases of gastric primary diffuse large B cell lymphoma were amplified from genomic or complementary DNA by a VH gene family-specific polymerase chain reaction method. The PCR products were directly sequenced and were compared to published germline sequences to analyse somatic mutations. Similarly to low grade MALT lymphomas 5/6 primary diffuse large B cell lymphomas show a pattern of somatic mutation in their rearranged VH genes, indicative of antigen selection and suggesting a role for antigens in lymphomagenesis. One case showed bi-allelic VH gene rearrangements, which were non-functional due to extensive deletions. Antigen selection could not be demonstrated or excluded. Antigen selection is a common feature in most analysed primary diffuse large B cell lymphomas, although some heterogeneity in the mechanisms involved in the lymphomagenesis of gastric primary diffuse large B cell lymphomas has not been excluded entirely (case 4).

Different gastritis features are linked to different gastric neoplasms

OBJECTIVES

Helicobacter pylori infection induces gastritis, which may evolve to carcinoma or lymphoma. Whether duration of infection and inflammation pattern determine the outcome of the neoplastic process is not known. The aim of this study was to investigate the features of the gastritis associated with neoplasia.

METHODS

Gastritis found in association with carcinoma (100 cases) and lymphoma (45 cases) were graded using the Sydney system.

RESULTS

In particular in the antrum, gastric carcinomas, in particular of the intestinal type, were associated with a chronic (94%, n = 34/36) atrophic (92%, n = 33/36) gastritis and intestinal metaplasia (81%, n = 29/36). In diffuse type carcinomas inflammation was either absent or mild. An active (64%, n = 16/25), chronic gastritis (100%, n = 25/25) with lymphoid hyperplasia (72%, n = 18/25) was found in marginal zone cell lymphoma.

CONCLUSIONS

Our study shows that the (pre)atrophic phases of inflammation are associated with gastric carcinomas. In contrast the active phase of inflammation, characterized by severe activity as well as severe chronicity, is found next to marginal zone cell lymphoma.

How reliable is histologic examination of bone marrow trephine biopsy specimens for the staging of non-Hodgkin lymphoma? A study of hairy cell leukemia and mantle cell lymphoma involvement of the bone marrow trephine specimen by histologic, immunohistochemical, and polymerase chain reaction techniques

Analysis of non-Hodgkin lymphoma (NHL) involvement of bone marrow trephine biopsy specimens by morphologic features and immunohistochemistry is often difficult, and the criteria for involvement are ill defined. We compared the morphologic and immunohistochemical analysis of B-cell NHL involvement with immunoglobulin heavy chain gene (IgH) rearrangement analysis by polymerase chain reaction (PCR) amplification of the complementarity determining region 3 (CDR3) in bone marrow biopsy specimens from patients with mantle cell lymphoma (n = 53) or hairy cell leukemia (n = 71). By combing morphologic features and phenotype, 54 specimens were considered positive, 62 negative, and 8 inconclusive. PCR analysis showed clonal IgH rearrangements in 46 positive and 6 inconclusive specimens. No clonal IgH rearrangements were present in 61 negative specimens. The 1 false-positive and most false-negative PCR results were likely due to sampling error or DNA degradation of the fixed tissues. In most cases, bone marrow involvement by NHL can be identified by histologic and immunohistochemical examination. Furthermore, clonality of the B-cell population can be detected by amplification of the IgH CDR3 on DNA extracted from bone marrow trephine biopsy sections, which can be helpful in cases diagnosed as inconclusive.

Blastic variant of mantle cell lymphoma shows a heterogenous pattern of somatic mutations of the rearranged immunoglobulin heavy chain variable genes

Mantle cell lymphoma is a distinct clinicopathological entity associated with t(11;14) and cyclin D1 overexpression. The majority of cases show uniform morphological and phenotypic features characterized by a monotonous proliferation of small-to-medium-sized irregular B cells that express CD5 and bright surface immunoglobulin IgM and IgD. By sequence analysis of the rearranged immunoglobulin heavy chain variable genes (VH), it has been shown that these lymphoma cells carry little if no somatic mutations, as described for the fetal CD5+ cells or B1 cells. Besides mantle cell lymphoma with classic histological features, a morphological variant of mantle cell lymphoma with blastic features and a more aggressive clinical course has been described. To investigate whether this variant is closely related, by the cell of origin, to typical cases, we analysed the presence and the pattern of somatic mutations of the VH genes in a series of nine cases diagnosed as such. Our cases of blastic mantle cell lymphomas rearrange most frequently VH4 and VH3 family genes. In three cases there was a complete homology to published germline genes, and a near complete homology was documented in another three. In contrast, the remaining three cases showed somatic mutations in their rearranged VH genes. Mutation analysis revealed evidence for antigen selection in one of these three cases. Taken together, these data are similar to those of normal adult-type B1 cells and those described for chronic lymphocytic leukaemia (CLL) but slightly different to those reported for classic mantle cell lymphoma. It is likely that blastic mantle cell lymphoma as well as CLL originates from adult-type B1 cells. More cases will need to be studied to determine whether classic mantle cell lymphoma is different from the blastic subtype and if it arises from fetal-type B1 cells.

Mutation analysis of the rearranged immunoglobulin heavy chain genes of marginal zone cell lymphomas indicates an origin from different marginal zone B lymphocyte subsets

Marginal zone cell lymphoma is a recently described entity among the non-Hodgkin's lymphomas. It likely originates from the marginal zone B cells in the spleen and equivalent cells in the lymph node and extranodal tissues. Recent evidence indicates that marginal zone B cells are functionally heterogeneous and may differ with respect to the pattern of somatic hypermutation in their Ig variable genes. To test whether marginal zone lymphomas may originate from different subsets of marginal zone B cells, we performed a sequence and mutation analysis of the rearranged Ig heavy chain (IgH) variable genes (VH) of a series of 14 cases of marginal zone lymphoma, occurring in the spleen (4), the lymph node (4), the stomach (2), the orbit (2), the tongue (1), and the skin (1). Our data show that marginal zone cell lymphomas preferentially rearrange the VH4, VH3, and VH1 family genes, without preference for any particular VH gene. Somatic mutations are present in 13 cases; one case of marginal zone cell lymphoma of the skin showed a germline configuration of the rearranged VH gene. Mutation analysis shows evidence of antigen selection in three cases of marginal zone cell lymphoma, one of the spleen, stomach, and orbit, respectively. No evidence of antigen selection was present in the other cases. These data indicate that marginal zone cell lymphomas may arise from different subsets of marginal zone B cells. In addition, lymphomagenesis may not be triggered by antigen in all cases of marginal zone cell lymphoma.

Lymph node histology in typical and atypical chronic lymphocytic leukemia

According to the French-American-British (FAB) proposal on the classification of chronic lymphoid leukemia (CLL), the disorder can be subdivided into typical and atypical CLL. We recently demonstrated the prognostic significance of this subgrouping and based on these results we suggested that typical and atypical CLL represent two closely related, but different entities. These results prompted us to investigate 42 patients diagnosed with CLL based on the results of lymph node biopsy in order to identify the histologic counterpart of the CLL variants. A first group of 14 cases showed a monomorphic proliferation of small round lymphocytes associated with the occurrence of small pseudofollicles. All these cases were diagnosed as typical CLL on peripheral blood (13 cases) or bone marrow smear (1 case). The remaining 28 cases showed aberrant histologic features characterized by the presence of large numbers of paraimmunoblasts and prolymphocytes, forming very large pseudofollicles, and/or by nuclear irregularities of the neoplastic cells. Based on peripheral blood smears (22 cases) or bone marrow smears (six cases), two cases showed no peripheral blood involvement, 21 cases were diagnosed as atypical CLL, and five as typical CLL. From these data we can conclude that a histologic counterpart of the CLL variants recognized in the FAB proposal does exist; moreover, our data may explain reports on lymph node involvement by CLL composed of small cleaved cells and clarify the occurrence of pseudofollicles in cases described as mantle cell lymphomas.

The clinical outcome of 65 cases of mantle cell lymphoma initially treated with non-intensive therapy by the British National Lymphoma Investigation Group

Mantle cell lymphoma (MCL) was first described as a distinct biological entity on the basis of its association with the t(11;14)(q13;q32) resulting in over-expression of the cyclin D1 gene. Recognition of the morphological, immunophenotypic and clinical characteristics of MCL has enabled the accurate diagnosis of this entity and appreciation of its poor prognosis. Most published series of patients with MCL have used anthracycline-containing regimens. In contrast the British National Lymphoma Investigation (BNLI) group have treated 65 patients with MCL with non-intensive 'low-grade lymphoma' therapy. The median overall survival of 57 months and progression-free survival of 24 months compares favourably with the more intensively treated series. Although the disease was generally more aggressive than other low-grade lymphomas, some patients were asymptomatic and had indolent disease. When compared to 1853 patients with non-MCL low-grade lymphomas entered on the BNLI database, patients were found on average to be older (P=0.02), to have more extranodal disease (P<0.00001), and a higher proportion to have a raised ESR (P=0.02) and a low serum albumin (P=0.002). Multivariate analysis of significant prognostic markers in all BNLI low-grade lymphomas failed to identify MCL as an independent prognostic factor.

Primary low-grade B-cell lymphoma of MALT-type occurring in the liver: a study of two cases

BACKGROUND/METHODS

Primary non-Hodgkin's lymphomas of the liver are rare. One specific clinico-pathological entity has been identified as hepatosplenic gamma/delta T-cell lymphoma. Recently, another distinct primary lymphoma of the liver has been recognised as primary low-grade hepatic B-cell lymphoma of mucosa-associated lymphoid tissue (MALT), based on a study comprising four cases. We analysed two additional cases of this particular non-Hodgkin's lymphoma, not only by morphology and phenotyping, but also by genotyping and cytogenetic analysis.

RESULTS

This type of non-Hodgkin's lymphoma is characterised by a dense lymphoid infiltrate, localised in the portal tracts, and is associated with lympho-epithelial lesions of the bile ducts, thereby mimicking hepatitis or an inflammatory bile duct disorder. In one of our cases, translocation t(3;14)(q27;q32) was identified as the sole cytogenetic abnormality. A high incidence of trisomy 3 has been associated with marginal zone B-cell lymphomas, and fluorescence in situ hybridisation as well as comparative genomic hybridisation studies have shown frequent involvement of the long arm of chromosome 3. Nevertheless, t(3;14)(q27;q32) involving BCL6 gene, located at 3q27, has not yet been found.

CONCLUSION

Our findings suggest a role for the BCL6 gene in the histogenesis of this particular lymphoma.

Philadelphia-like translocation t(9;22)(q34;q11) found in a follicular lymphoma involving not BCR and ABL but IGL-mediated rearrangement of an unknown gene on 9q34

In a case of follicular center cell lymphoma (FCCL) without evidence of histologic progression towards a high-grade lymphoma, t(9;22)(q34;q11) was found simultaneously with a t(14;18)(q32;q21) and a t(8;14)(q24;q32). Molecular studies of this case showed BCL2 and MYC rearrangements in addition to the rearrangements of immunoglobulin heavy (IGH) and lambda (IGL) loci. Investigation of the t(9;22) using Southern blot and RT-PCR analysis failed to detect M-bcr or m-bcr rearrangements of BCR. Two-color fluorescence in situ hybridization (FISH) with ABL and BCR probes revealed presence of a "fusion" signal, but its atypical localization [der(9)] and gene order [cen-ABL-BCR-tel] indicated that this translocation differed from the t(9;22) in chronic myeloid leukemia and did not involve either ABL or BCR. In addition, further FISH analysis using 9q34- and 22q11-specific probes localized the breakpoint on chromosome 9 distal to the NOTCH1 gene and the breakpoint on 22q11 in the IGL gene cluster. These results indicate an IGL-mediated rearrangement of an unknown gene at 9q34 that together with BCL2 and MYC might be involved in the lymphomagenesis of the present case of FCCL and perhaps in other cases of non-Hodgkin lymphoma in which t(9;22) is sporadically occurring.

BCL6 gene rearrangements also occur in marginal zone B-cell lymphoma

Marginal zone B-cell lymphoma (MZBCL) represents a distinct subtype of B-cell non-Hodgkin's lymphoma (NHL) which has been recently recognized and defined as a disease entity. Cytogenetically, these lymphomas reveal a high prevalence of trisomy 3, and recent data obtained by comparative genomic hybridization indicate that the chromosomal regions 3q21-23 and 3q25-29 might be of particular pathogenetic significance. We identified structural chromosomal abnormalities involving the region 3q27 and rearrangements of the BCL6 proto-oncogene in three out of 34 (9%) well-defined cases of extranodal, nodal and splenic MZBCL using cytogenetic analysis. Southern blot, and fluorescence in situ hybridization (FISH). All three cases were characterized by a t(3;14)(q27;q32). Two of them showed additional chromosomal abnormalities including trisomy 3, which was found in one case. The patients displayed extranodal disease and did not demonstrate any striking clinical and histological differences when compared with MZBCL lacking BCL6 rearrangement. The present study for the first time demonstrates the occurrence of t(3;14)/BCL6 gene rearrangement in MZBCL, thus suggesting a role of the BCL6 proto-oncogene in the pathogenesis of MZBCL.

The monoclonal antibody ALK1 identifies a distinct morphological subtype of anaplastic large cell lymphoma associated with 2p23/ALK rearrangements

Anaplastic large cell lymphoma (ALCL) is a heterogeneous group of diseases by morphology, phenotype, genotype, and clinical presentation. Using a new monoclonal antibody (ALK1) that recognizes the native anaplastic lymphoma kinase (ALK) protein as well as the fusion product of the t(2;5)(p23;q35), nucleophosmin (NPM)/ALK, we investigated for ALK expression cases diagnosed as ALCL as well as lympho-proliferative disorders possessing overlapping features with ALCL. Thirteen cases showed cytoplasmic staining of the neoplastic cells. These cases were characterized by a fairly uniform morphology and occurred in children and young adults as a systemic disease. All other cases comprising T or null ALCL (17 cases), B ALCL (8 cases), Hodgkin's disease (HD) (15 cases), HD-like ALCL (23 cases), and lymphomatoid papulosis (9 cases), were negative for ALK expression. Translocation t(2;5)(p23;q35) was found by classical cytogenetics or interphase fluorescence in situ hybridization in 8 of the ALK1-positive cases and by reverse transcription-polymerase chain reaction in 1 other case. Two additional ALK1-positive cases with an abnormal karyotype, but without t(2;5)(p23;q35), showed by fluorescence in situ hybridization analysis a cryptic NPM/ALK gene fusion caused by an insertion of ALK near NPM in one case and a translocation of ALK to 2q35 as a result of an indiscernible inv(2)(p23q35) in the other. The latter variant translocation points to a localization of an unknown gene at 2q35 that, like NPM, might deregulate ALK and be involved in the pathogenesis of ALCL. In summary, immunohistochemistry with ALK1 antibody allows the identification of a distinct subgroup within the ALCL of T or null phenotype that is associated with 2p23 abnormalities and lacks the marked histological pleomorphism described in ALCL in general. Whereas immunostaining is the most sensitive method to identify this group, it does not help to additionally clarify the relationship among ALCL, HD, and HD-like ALCL.

Marginal zone B-cell lymphomas including mucosa-associated lymphoid tissue type lymphoma (MALT), monocytoid B-cell lymphoma and splenic marginal zone cell lymphoma and their relation to the reactive marginal zone

The marginal zone of the B follicle represents a well-defined compartment of the B area. Its cellular composition is distinct from that of the follicle centre, from which it also differs in its functional role in the immune response. Several newly identified lymphoma entities, e.g. extranodal MALT type lymphoma, nodal monocytoid B-cell lymphoma and splenic marginal zone B-cell lymphoma, display in common a very peculiar organoid growth pattern reminiscent of the marginal zone. Moreover, their neoplastic components share morphologic and phenotypic similarities to the cellular components of the marginal zone. The clinical characteristics of these various marginal zone cell lymphomas may differ depending of the organ which is involved. Nevertheless, they all share common cytogenetic abnormalities suggesting a common pathogenesis.

Characteristic pattern of chromosomal gains and losses in marginal zone B cell lymphoma detected by comparative genomic hybridization

Marginal zone B cell lymphoma (MZBCL) represents a distinct subtype of B cell non-Hodgkin's lymphoma, which has been recently recognized and defined as a disease entity. We investigated 25 cases (18 at primary diagnosis and seven during the course of disease) of MZBCL by comparative genomic hybridization (CGH) and compared these results with cytogenetic, fluorescence in situ hybridization (FISH), and Southern blot data. Twenty of the 25 cases (80%) showed gains (total 49) or losses (total 15) of genetic material. In extranodal, nodal, and splenic MZBCL, material of chromosomes 3 (52% of cases), 18 (32%), X (24%), and 1q (16%) was most frequently gained, whereas losses predominantly involved chromosomes 17 (16%) and 9 (12%). High-level amplifications involving the regions 18q21-23 and 18q21-22, respectively, were detected in two cases. Gains of chromosomes 1q and 8q and losses of chromosome 17 or 17p occurred more frequently in relapsed or progressive lymphomas. For all of the frequently affected chromosomes, CGH allowed narrowing of the relevant subregions including 3q21-23, 3q25-29 and 18q21-23. By Southern blot analysis, the BCL2, BCL6, and CMYC proto-oncogenes were found to be a part of the over-represented regions in two cases, one case, and two cases, respectively, with gains involving 18q, 3q or 8q. In 13 cases, CGH revealed chromosomal imbalances which were not detected by cytogenetic analysis but could be confirmed by FISH or Southern blot analysis in all cases investigated. On the other hand, CGH failed to detect trisomy 3, trisomy 18, and deletion 7q in three cases with a low proportion of tumor cells bearing these abnormalities, as shown by interphase FISH. The characteristic pattern of chromosomal gains and losses detected in this study confirms the distinct nature of MZBCL and may point to chromosomal regions involved in the pathogenesis of these neoplasms.

Further considerations on the Revised European-American Lymphoma classification

The proposal from the International Lymphoma Study Group (ILSG) of a new classification for lymphoid neoplasm, known as the Revised European-American Lymphoma (REAL) classification, has been received by clinicians and pathologists with mixed reactions. Numerous letters, editorials, and abstracts have been published in the past year praising and criticizing this proposal. The feasibility as well as the clinical validity of the ILSG proposal has been tested in retrospective studies based on large multicenter trials, and a large multi-institutional effort to prove or disprove the validity of the REAL classification was undertaken by the International Non Hodgkin's Lymphoma Classification Project. All these studies seems to confirm the usefulness of the REAL classification. Besides the overall evaluation of the ILSG proposal, the clinical validity of the newly defined entities (eg, mantle cell lymphoma, marginal zone cell lymphoma) has been shown by these and other retrospective studies. However, the main objection of clinicians remains the lack of grouping of lymphoma entities according to their clinical behavior, which we as pathologists believe to be the clinician's task.

BCL-6 expression in reactive lymphoid tissue and in B-cell non-Hodgkin's lymphomas

Chromosomal abnormalities involving 3q27 have recently been associated with diffuse large B-cell lymphomas and, less frequently, with follicular lymphomas. Molecular studies have led to the identification of the BCL-6/LAZ-3 gene, located at 3q27 and coding for a putative zinc-finger protein that might act as a transcriptional regulator during cell differentiation and development. Rearrangement of BCL-6 results in truncation of the gene in its 5' portion, leaving the protein intact; a resultant deregulation of its expression has been hypothesized. In order to test this hypothesis, the expression of BCL-6 protein was investigated in human reactive lymphoid tissue and compared with a group of non-Hodgkin's lymphomas (NHLs) with or without 3q27 anomalies and/or BCL-6 gene rearrangement. BCL-6 protein is consistently expressed in reactive lymphoid tissues, where it is restricted to the follicle centre. The protein is also widely expressed in NHL: all follicular lymphomas tested showed a pattern of expression similar to the reactive B follicle, independently of the presence of BCL-6 gene rearrangement and/or 3q27 anomalies. In the diffuse large B-cell lymphomas, there was more variation in BCL-6 expression, but a correlation with 3q27 anomalies and/or BCL-6 rearrangement was not found. Deregulation of the BCL-6 gene did not result in an aberrant tissue expression as detected by immunohistochemistry.

Clinical analysis of 670 cases in two trials of the European Organization for the Research and Treatment of Cancer Lymphoma Cooperative Group subtyped according to the Revised European-American Classification of Lymphoid Neoplasms: a comparison with the Working Formulation

In the Working Formulation (WF), non-Hodgkin's lymphomas (NHL) are grouped according to their clinical behavior. These disorders are listed as entities defined by morphology, phenotype, and cytogenetics in the proposed Revised European-American Classification of Lymphoid Neoplasms (REAL), the clinical relevance of which is still debated. We analyzed 670 NHL cases included in two randomized clinical trials (EORTC 20855 WF-intermediate/high-grade and 20856 WF-low-grade malignancy) with histologic material available for review. Based on hematoxylin-eosin-stained sections, 77% of cases could be subtyped. Immunophenotyping was considered to be mandatory only in diagnosing T-cell lymphoma and anaplastic large-cell lymphoma. Of 522 cases subtyped, 11% were mantle cell lymphoma (MCL), 5% were marginal zone B-cell lymphoma (MZBCL), 46% were follicle center lymphoma, and 32% were diffuse large B-cell lymphoma. Statistical analysis and comparisons between classifications were made only within each trial and treatment group. MCL and MZBCL were characterized by a shorter median survival (3.4 and 4.1 years, respectively) in comparison with low- and intermediate-grade WF groups (> 9.3 and 5.8 years, respectively). In terms of progression-free survival, MCL showed a behavior similar to the low-grade group, with frequent relapses. Follicle center cell lymphomas behaved as low-grade lymphomas as defined by the WF and diffuse large B-cell lymphomas as the WF-intermediate grade group. Because several NHL entities have a clinical behavior of their own, their recognition by the REAL classification offers clinicians additional information that is not obtained when the WF is used.

Small B cell NHL and their leukemic counterpart: differences in subtyping and assessment of leukemic spread

Three subtypes of small lymphocytic lymphoma were studied, namely B cell chronic lymphocytic leukemia (B-CLL), mantle cell lymphoma (MCL) and follicle center lymphoma (FCL). Agreement between tissue diagnosis, based on the proposal for a revised European-American classification of lymphoid neoplasms from the International Lymphoma Study Group, and the cytomorphological diagnosis on peripheral blood and/or bone marrow smears, using the proposals for the classification of chronic (mature) B and T lymphoid leukemias of the French-American-British Cooperative Group, was studied. Full agreement was found in 90% of the CLL and 82% of the FCL cases. In MCL cases, agreement was 65% including all cases classified as intermediate/mantle zone lymphoma according to FAB criteria. The incidence of bone marrow involvement detection in trephines compared to smears was equal in CLL (both 100%) and slightly higher in MCL (56 vs 48.5%); in FCL, however, trephine biopsies provided more reliable material (71 vs 35%).

Trisomy 3 in marginal zone B-cell lymphoma: a study based on cytogenetic analysis and fluorescence in situ hybridization

Trisomy 3 represents the most frequent and consistent chromosomal abnormality characterizing the recently defined entity marginal zone B-cell lymphoma (MZBCL). By cytogenetic analysis and/or fluorescence in situ hybridization (FISH) on interphase nuclei we found in increased copy number of chromosome 3 in 22/36 (61%) successfully analysed cases, including 8/12 cases with extranodal MZBCL, 8/13 cases with nodal MZBCL, and 6/11 patients with splenic MZBCL. Sensitivity of interphase cytogenetics was somewhat higher than that of conventional cytogenetic investigation. Structural chromosomal changes involving at least one chromosome 3 were seen in 11/20 cases with an increased copy number of chromosome 3: +de(3)(p13) was demonstrated in three cases, and was the sole chromosomal abnormality in one of them; +i(3)(q10) was seen in two other patients; and rearrangements involving various breakpoints on the long arm of chromosome 3 were found in the remaining cases. FISH on metaphase spreads confirmed these structural abnormalities and additionally showed two unexpected translocations involving chromosome 3. We conclude that: (1) trisomy 3 occurs in a high proportion of extranodal, nodal and splenic MZBCL; (2) FISH on interphase nuclei is an additional and sensitive tool in detecting an increased copy number of chromosome 3 in MZBCL; (3) additional structural abnormalities involving the long arm of chromosome 3 are frequent but non-recurrent and are perhaps secondary changes; and (4) abnormalities such as +del(3)(pl3) and +i(3)(q10) suggest that genes located on the long arm of chromosome 3 are of particular importance in the pathogenesis of MZBCL.