Clinical significance of bcl-2-MBR gene rearrangement and protein expression in diffuse large-cell non-Hodgkin's lymphoma: an analysis of 83 cases

Unique phenotypic profile of monocytoid B cells: differences in comparison with the phenotypic profile observed in marginal zone B cells and so-called monocytoid B cell lymphoma

Monocytoid B cells (MBCs) are a subset of B cells that may be recognized in several reactive and tumoral lymph node conditions, including toxoplasmic lymphadenitis, infectious mononucleosis, and Hodgkin's lymphoma. Although this is a commonly observed cell population, which has even given its name to a type of lymphoma, MBC lymphoma, scarcely any information is available about the function and characteristics of this cell type. A relationship with marginal zone (MZ) B lymphocytes has been claimed for MBCs, but this has not yet been fully proven. Indeed, specific markers for MBCs are still lacking, which has made it difficult to analyze their relationship with other B cell subpopulations and confirm the existence of tumors deriving from this B cell subset. We used a panel of cell cycle markers to explore the characteristics of MBCs and their relationship with MZ B cells, nodal MZ lymphoma, and splenic MZ lymphoma. We therefore compared the phenotypic profile of MBCs in different conditions with normal MZ B cells within the spleen and mesenteric lymph nodes, with a group of seven cases of nodal MZ/MBC lymphoma and another group of five cases of splenic MZ lymphoma. MBCs were mainly in the G(0) to G(1) phases, as deduced from the presence of a proportion of between 10 and 35% Ki67-positive cells, whereas very low expression was observed with cyclin A and cyclin B staining. Nests of MBCs were clearly labeled by the expression of p21(WAF1), a cyclin-dependent kinase inhibitor (CKI), rarely detectable in benign lymphocytes, and by cyclin E. Basically all MBCs were bcl-2-negative, and high cyclin D2 and cyclin D3 were also detected in these cells, at proportions and intensities above expected levels, when the percentage of proliferating cells was taken into account. p27(KIP1) expression was characterized by homogeneous reactivity, higher than that observed in other B cell populations with a relatively high-growth fraction. Immunoglobulin staining showed undetectable light and heavy chains. However, splenic MZ cells, nodal MZ lymphoma, and splenic MZ lymphoma showed a distinct expression of IgM and bcl-2, with high p27 (KIP1) nuclear expression and undetectable or low levels of cyclin A, B, E, or D, or p21(WAF1) expression. The data from this study show an unexpected immunophenotype in MBCs, different from the one observed in splenic and lymph node MZ B cells. This suggests that either MBCs are a unique B cell population from a distinct cell lineage, or if related to MZ cells, they would represent a definite differentiation stage characterized by a distinctive immunophenotype. They also show so-called MZ/MBC lymphoma to be more closely related to lymph node and splenic MZ B cells, as they do not share the most distinctive features of MBCs.

Clinical drug-resistant nodular sclerosing Hodgkin's lymphoma is associated with decreased bcl-2 expression in the surrounding lymphocytes and with increased bcl-2 expression in the Reed-Sternberg cells

Identification of patients with Hodgkin's lymphoma who are primary refractory to chemotherapy will have great impact on treatment planning. Several studies have indicated that up-regulation of the bcl-2 proto-oncogene expression in non-Hodgkin's lymphoma can cause resistance to chemotherapeutic drugs. For this reason we investigated the relationship between expression of bcl-2, the pro-apoptotic protein Bax and MIB-1 with clinical drug-resistance in Hodgkin's lymphoma.

METHODS AND RESULTS

Seven patients with nodular sclerosis Hodgkin's lymphoma under 40 years of age, who failed to achieve complete remission upon primary chemotherapy and 10 matched patients who did achieve complete response were selected from the Eindhoven Cancer Registry. Tissue sections from both groups of patients were stained for bcl-2, Bax and MIB-1. In the non-responding patients Reed-Sternberg cells expressed bcl-2 more frequently using a cut-off point of <25% to indicate negative cells (P = 0.04), whereas no differences were observed in the expression of Bax and MIB-1. In non-responding patients the lymphocytes surrounding Reed-Sternberg cells expressed bcl-2 less frequently (P = 0.002), using a cut-off point of < 25%, whereas no difference was observed in the expression of Bax and MIB-1.

CONCLUSION

A high percentage of Reed-Sternberg cells expressing bcl-2 protein and a low expression of bcl-2 proteifi in the surrounding lymphocytes is associated with treatment-failure, and subsequent poor survival in young patients with nodular sclerosing Hodgkin's lymphoma. These results need further validation in larger studies.

Recurring chromosomal abnormalities in non-Hodgkin's lymphoma: biologic and clinical significance

Non-Hodgkin's lymphomas (NHLs) are a group of clinically important neoplasms with a complex biology that makes their classification and treatment difficult. Their incidence is increasing and they cause significant morbidity and mortality. NHLs result from transformation of B and T/natural killer (NK) cells. Their genetic hallmark is chromosomal translocations resulting from aberrant rearrangements of IG and TCR genes, which lead to inappropriate expression of genes at reciprocal breakpoints that regulate a variety of cellular functions, including gene transcription, cell cycle, apoptosis, and tumor progression. Cytogenetics followed by molecular genetic analysis of some of the recurring translocations continues to provide new insights into lymphomagenesis and cell biology. More recently, chromosomal and gene amplification and gene deletion have been recognized as frequent genetic changes that may play a role in lymphoma progression and clinical behavior. In this review, cytogenetic data pertaining to recurring chromosomal changes on lymphomas are reviewed and examined in relation to their relevance to lymphoma development, classification, and clinical behavior.

CD10 and BCL-6 expression in paraffin sections of normal lymphoid tissue and B-cell lymphomas

In this study the authors explored the value of immunostaining for follicular center B-cell markers, BCL-6 and CD10, in paraffin sections as a tool for the differential diagnosis of B-cell lymphomas. The cases studied comprised reactive lymphoid hyperplasia (RLH; n = 19), follicular lymphoma (FL; n = 50), low-grade mucosa-associated lymphoid tissue (MALT) lymphoma (n = 24), mantle cell lymphoma (n = 19), splenic marginal zone lymphoma (n = 13), diffuse large B-cell lymphoma (DLBCL; n = 54), Burkitt's lymphoma (BL; n = 20), nodular lymphocyte predominance Hodgkin's disease (NLPHD; n = 16), and classic Hodgkin's disease (CHD; n = 13). In RLH, CD10 and BCL-6 were expressed almost exclusively by the follicular center cells. In contrast in FL, the expression of CD10 (39/50) and BCL-6 (34/36) was seen in both follicular and interfollicular neoplastic B cells. Marginal zone/MALT lymphomas and mantle cell lymphoma were always negative. In DLBCL the expression was variable for both CD10 (21/54) and BCL-6 (39/47), with some tumors, including cases of transformed follicular lymphoma (9/10), coexpressing CD10 and BCL-6, and others expressing only BCL-6, and a small group expressing neither marker, possibly reflecting the underlying primary pathogenetic events such as the rearrangement of BCL-2 or BCL-6 genes. BL was always both CD10 and BCL-6 positive. In NLPHD the L&H cells expressed BCL-6 (11/13) but not CD10, whereas in CHD BCL-6 expression was seen in half of the cases. This study demonstrates that both CD10 and BCL-6 are reliable markers of follicular center B-cell differentiation. CD10 and BCL-6 immunostaining have an important role in differential diagnosis of FL from RLH and other low-grade B-cell lymphomas. The results also suggest that a CD10/BCL-6 expression pattern may be helpful in identifying main subsets of DLBCL. However, additional studies comparing genotype with immunophenotype are required.

Expression of c-Myc and p53 correlates with clinical outcome in diffuse large B-cell lymphomas

We performed a retrospective immunohistochemical study of the relationships between clinical manifestations and outcomes of diffuse large B-cell lymphoma (DLBCL) and expression of oncogenic proteins in 21 cases of DLBCL at various clinical stages. Cases of nodal origin expressed p53 more often and presented with high clinical stage more frequently than those of extranodal origin. Expression of c-Myc or p53, but not Bcl-6, Bcl-2, or Bcl-1, showed a statistically significant positive correlation with high clinical stage at presentation and with high or high-intermediate risk. Coexpression of c-Myc and p53 occurred in 7 of 12 patients with high clinical stage but was absent in patients with low clinical stage; coexpression was more frequent in patients with high or high-intermediate risk than in patients with low or low-intermediate risk. Four patients with this coexpression pattern demonstrated an unusually aggressive clinical course (median survival, 7 months). Coexpression of c-Myc and p53 seems to be a better indicator than the MIB1 proliferative index for identification of a cohort of aggressive disease in patients with DLBCL.

Recent advances in the molecular pathogenesis of lymphomas

Most human lymphomas remain heterogeneous biologic entities in spite of recent advances in the description of their clinical presentation, cellular morphology, immunophenotype, and genotype. Elucidation of genetic alterations causing malignant transformation may explain pathogenesis, refine differential diagnosis, clarify prognosis, and provide rational basis for new therapy. During the last year the expression of anaplastic lymphoma kinase clarified presentation and provided clues toward the outcome of anaplastic large cell lymphoma; the breakpoints of t(2;5) were mapped; constitutive activation of anaplastic lymphoma kinase by a chromosomal inversion was described; transformation was shown to be independent of nuclear localization of anaplastic lymphoma kinase; and phospholipase C-gamma was identified as a molecular target for the kinase activity of anaplastic lymphoma kinase. Molecular characterization of recurrent chromosome abnormalities has identified new candidate oncogenes: bcl-9, bcl-10, PAX-5, MMSET, and c-maf. Their precise role in malignant transformation, and the frequency of their alteration in lymphoma and myeloma, is not yet defined. The expression of the antiapoptotic protein bcl-2 on aggressive lymphomas was shown to be associated with inferior disease-free survival by several investigators. This may be a target of pharmacologic reduction of bcl-2 levels. Can these advances in molecular pathogenesis improve cure rates for lymphoma? The spectacularly successful molecular modeling of inhibitors for HIV protease suggests that this may be an attainable objective.

BCL2 overexpression in diffuse large B-cell lymphoma

Translocation (14;18)(q32;q21), which is detected in 20-30% of diffuse large B-cell lymphomas (DLBCL), is regarded as a major mechanism for BCL2 protein overexpression. Nevertheless, BCL2 overexpression is not always caused by t(14;18), because it is often detected in lymphomas without BCL2 rearrangement. Recent studies have shown that increased expression of BCL2 may also result from BCL2 gene amplification in DLBCL. Similarly, it has been speculated that the mutations of the open reading frame might cause increased expression of BCL2 by affecting the interactions of BCL2 with other proteins. The results obtained from studies on the association of BCL2 protein overexpression with survival of DLBCL are controversial, although a correlation with decreased overall survival seems to exist. However, BCL2 rearrangement does not seem to have any major association with poor prognosis, but it is difficult to assess its true impact on prognosis due to differences in treatment and follow-up, and methodologies applied to study the BCL2 rearrangement. This review summarizes the BCL2 expression studies in DLBCL and discusses the prognostic relevance of BCL2 overexpression and its mechanisms.

Expression of BAG-1 in invasive breast carcinomas

PURPOSE

The purpose of this study was to retrospectively evaluate the expression of BAG-1 in invasive breast carcinomas. The intensity and subcellular distribution of BAG-1 expression was correlated with conventional prognostic factors and with disease-free and overall survival.

PATIENTS AND METHODS

One hundred forty patients diagnosed with invasive breast cancer in St. John's, Newfoundland, between 1986 and 1996 were included in the study. The median follow-up of the study was 8 years. Expression of BAG-1 was determined by immunohistochemical staining of paraffin-embedded breast tumor tissues.

RESULTS

Of the 140 breast carcinomas examined, 77.1% were positive for BAG-1 expression. Except for differentiation, no correlation was observed between BAG-1 expression and conventional prognostic factors such as age, histology, stage, and estrogen and progesterone receptor status. In multivariate analysis, BAG-1 expression was significantly associated with shorter disease-free (P =.0052) and overall survival (P =.0033). Patients whose tumors expressed nuclear BAG-1 tended to have a shorter disease-free (63 v 84 months; P = 0.4493) and overall (69 v 99 months, P =.1009) survival.

CONCLUSION

BAG-1 is overexpressed in the majority of invasive breast carcinomas. Although BAG-1 did not correlate with conventional prognostic factors, its overexpression, especially the nuclear expression, may be associated with a shorter disease-free and overall survival. Our preliminary data strongly indicate that further investigation is warranted to define the role of BAG-1 as an independent prognostic factor in patients with newly diagnosed breast cancer.

Bcl-2 gene rearrangements and apoptosis rates in patients with non-Hodgkin's lymphoma during chemotherapy

OBJECTIVES

Overexpression of the bcl-2 gene as a result of the t(14,18) translocation leads to neoplastic transformation by suppressing apoptosis. However, apoptotic cell death in response to chemotherapy has not been investigated. This study was planned with the aim to investigate the association between bcl-2 gene rearrangements and apoptotic changes during chemotherapy in patients with non-Hodgkin's lymphoma.

DESIGN AND METHODS

Lymphocytes from 33 patients were collected before and during chemotherapy. Bcl-2 gene rearrangements were investigated by PCR. Apoptotic cell death was analyzed by enzyme immunoassay.

RESULTS

In 24 cases, mbr gene rearrangements were detected. Apoptosis was successfully induced by chemotherapy in 48% of patients. Two characteristic, clearly distinguishable apoptotic response patterns with transient peaks either following the first or the third course were observed. It was found that apoptosis rates measured after the first course exactly reflect the final response. No correlation was found between bcl-2 gene rearrangements and apoptosis.

CONCLUSIONS

Apoptotic cell death rates show transient changes during chemotherapy. Because the midterm response can be misleading, the apoptotic response should be evaluated following the first course of chemotherapy.

Clinical Relevance of BCL2, BCL6, and MYC Rearrangements in Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLCL) is characterized by a marked degree of morphologic and clinical heterogeneity. We studied 156 patients with de novo DLCL for rearrangements of the BCL2, BCL6, and MYC oncogenes by Southern blot analysis and BCL2 protein expression. We related these data to the primary site of presentation, disease stage, and other clinical risk factors. Structural alterations of BCL2, BCL6, and MYC were detected in 25 of 156, 36 of 116, and 10 of 151 patients, respectively. Three cases showed a combination of BCL2 and BCL6 rearrangements, and two cases had a combination of BCL6 and MYC rearrangements. BCL2 rearrangement was found more often in extensive (39%) and primary nodal (17%) lymphomas than in extranodal cases (4%) (P = .003). BCL2 rearrangement was present in none of 40 patients with stage I disease, but in 22% of patients with stage II to IV (P = .006). The presence of BCL2 rearrangements did not significantly affect overall survival (OS) or disease-free survival (DFS). In contrast, high BCL2 protein expression adversely affected both OS (P = .008) and DFS (P = .01). BCL2 protein expression was poorly correlated with BCL2 rearrangement: only 52% of BCL2-rearranged lymphomas and 37% of BCL2-unrearranged cases had high BCL2 protein expression. Rearrangement of BCL6 was found more often in patients with extranodal (36%) and extensive (39%) presentation versus primary nodal disease (28%). No significant correlation was found with disease stage, lymphadenopathy, or bone marrow involvement. DFS and OS were not influenced by BCL6 rearrangements. MYC rearrangements were found in 16% of primary extranodal lymphomas, versus 2% of primary nodal cases (P = .02). In particular, gastrointestinal (GI) lymphomas (5 of 18 cases, 28%) were affected by MYC rearrangements. The distinct biologic behavior of these extranodal lymphomas was reflected by a high complete remission (CR) rate: 7 of 10 patients with MYC rearrangement attained complete remission and 6 responders remained alive for more than 4 years, resulting in a trend for better DFS (P = .07). These data show the complex nature of molecular events in DLCL, which is a reflection of the morphologic and clinical heterogeneity of these lymphomas. However, thus far, these genetic rearrangements fail as prognostic markers.

© 1998 by The American Society of Hematology.

Clinical Relevance of BCL2, BCL6, and MYC Rearrangements in Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLCL) is characterized by a marked degree of morphologic and clinical heterogeneity. We studied 156 patients with de novo DLCL for rearrangements of the BCL2, BCL6, and MYC oncogenes by Southern blot analysis and BCL2 protein expression. We related these data to the primary site of presentation, disease stage, and other clinical risk factors. Structural alterations of BCL2, BCL6, and MYC were detected in 25 of 156, 36 of 116, and 10 of 151 patients, respectively. Three cases showed a combination of BCL2 and BCL6 rearrangements, and two cases had a combination of BCL6 and MYC rearrangements. BCL2 rearrangement was found more often in extensive (39%) and primary nodal (17%) lymphomas than in extranodal cases (4%) (P = .003). BCL2 rearrangement was present in none of 40 patients with stage I disease, but in 22% of patients with stage II to IV (P = .006). The presence of BCL2 rearrangements did not significantly affect overall survival (OS) or disease-free survival (DFS). In contrast, high BCL2 protein expression adversely affected both OS (P = .008) and DFS (P = .01). BCL2 protein expression was poorly correlated with BCL2 rearrangement: only 52% of BCL2-rearranged lymphomas and 37% of BCL2-unrearranged cases had high BCL2 protein expression. Rearrangement of BCL6 was found more often in patients with extranodal (36%) and extensive (39%) presentation versus primary nodal disease (28%). No significant correlation was found with disease stage, lymphadenopathy, or bone marrow involvement. DFS and OS were not influenced by BCL6 rearrangements. MYC rearrangements were found in 16% of primary extranodal lymphomas, versus 2% of primary nodal cases (P = .02). In particular, gastrointestinal (GI) lymphomas (5 of 18 cases, 28%) were affected by MYC rearrangements. The distinct biologic behavior of these extranodal lymphomas was reflected by a high complete remission (CR) rate: 7 of 10 patients with MYC rearrangement attained complete remission and 6 responders remained alive for more than 4 years, resulting in a trend for better DFS (P = .07). These data show the complex nature of molecular events in DLCL, which is a reflection of the morphologic and clinical heterogeneity of these lymphomas. However, thus far, these genetic rearrangements fail as prognostic markers.

© 1998 by The American Society of Hematology.

Evaluation and management of the "new" lymphoma entities: mantle cell lymphoma, lymphoma of mucosa-associated lymphoid tissue, anaplastic large-cell lymphoma, and primary mediastinal B-cell lymphoma

Non-Hodgkin's lymphomas (NHL) represent a major health problem worldwide, and incidence has been on the rise continuously for the last few decades. It is estimated that approximately 55,000 new cases of NHL will be diagnosed in the United States in 1998 and that slightly fewer than 25,000 patients will die of treatment failure or recurrent disease. The rising incidence of NHL is related not only to the acquired immunodeficiency syndrome epidemic but to also a steady increase in the number of cases diagnosed in older patients without immunosuppression. The new pathologic classification of NHL (revised European-American lymphoma classification, REAL) developed by the International Lymphoma Study Group (ILSG) is already resulting in more accurate disease-specific epidemiologic and clinical investigations. These studies have brought a new awareness of the existence and the relative prevalence of discrete NHL subtypes that appear to predominate among patients in different populations according to age, sex, geographic distribution, and predisposing conditions. This developing database has also the potential to result in the discovery of specific environmental causes, predisposing genetic factors, and therapeutic approaches. Some of the entities defined in the REAL classification, such as follicular lymphomas, diffuse B large-cell lymphomas, and T-cell lymphoblastic lymphomas, were already well described in the older classification systems (Kiel and Working Formulation). Others, such as mantle cell lymphoma, (MCL) anaplastic large-cell lymphoma (ALCL), lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), and primary mediastinal B-cell lymphoma (PMBCL) are relatively new members of the family, and accurate data on their clinicopathologic features and natural histories have only recently begun to emerge. This review presents in detail the most recent data on the clinical presentation of, diagnostic evaluation of, and treatment options for the most common of the new NHL entities: MCL, MALT lymphoma, CD30+ (Ki-1+) ALCL, and PMBCL. These four entities combined represent approximately 20% of all cases of NHL and exemplify well the broad clinicopathologic spectrum of NHL and the diagnostic and therapeutic challenges facing those who care for patients affected by these conditions.

Primary central nervous system lymphomas in immunocompetent individuals: histology, Epstein-Barr virus genome, Ki-67 proliferation index, p53 and bcl-2 gene expression

Epstein-Barr virus (EBV) has been detected in the large majority of HIV-related primary central nervous system lymphomas (PCNSL) suggesting a pathogenetic role of the virus. Unlike HIV-related PCNSL, conflicting data exist with regard to the presence of EBV in non immunodeficiency-related (sporadic) PCNSL. For this reason, a population based material of 41 sporadic PCNSL was analysed for the presence of EBV genome (EBER, BHLF) using RNA in situ hybridisation (RISH). Furthermore, the expression of the gene products of the bcl-2 oncogene and the p53 tumor suppressor gene and the tumor growth fraction reactive with the monoclonal antibody Ki-67 have been evaluated. All cases but two were EBV genome negative. In the two positive cases less than 5% of tumor cells showed EBER positivity. In contrast, more than 75% of cells morphologically belonging to the tumor-cell population stained positively for EBER in two cases of HIV related PCNSL. Immunostaining for the bcl-2 oncoprotein was positive in 28 (72%) of 39 cases examined. In most cases more than 75% of tumor cells showed cytoplasmic expression. Of 37 cases investigated for p53 expression, 21 (57%) stained positively. However, in the large majority of positive cases less than 10% of the neoplastic cells stained. The percentage of Ki-67 positive cells ranged between 10% and 80% with a mean of 50%. The expression of the p53 and bcl-2 oncoproteins and the growth fraction did not have any prognostic impact. We conclude that the EBV genome is rarely detected in sporadic PCNSL, indicating that a pathogenetic role of EBV is unlikely. Like extracerebral B-cell lymphomas a large fraction of PCNSL expresses the p53 and bcl-2 oncoproteins, a feature, however, which does not seem to have prognostic implications.

BCL-2 Expression Correlates With Lower Proliferative Activity in the Intermediate- and High-Grade Non-Hodgkin's Lymphomas: An Eastern Cooperative Oncology Group and Southwest Oncology Group Cooperative Laboratory Study

An inverse relationship between BCL-2 expression and cell cycle transition has been suggested by recent studies in murine models. To investigate the clinical relevance of these laboratory studies, a group of 116 paraffin-embedded non-Hodgkin's lymphoma (NHL) biopsy specimens (Working Formulation Groups D-H, and J) from a cooperative group study of cellular DNA content were analyzed for the 14;18 translocation using polymerase chain reaction (PCR)-based methods and, if sufficient tissue remained, for BCL-2 and BAXexpression by immunohistochemistry. The results of these studies were then compared with the results of the previously performed flow cytometric analysis of ploidy and proliferative activity (S-phase-fraction). BCL-2 expression was inversely associated with proliferative activity (P = .001; n = 41), but there was no association between staining for Bax and %S-phase. Ploidy was not associated with either BCL-2 or BAX expression. The t(14;18) was detected in 21 of the 54 cases in which PCR-amplifiable DNA was recovered; 20 of these occurred at the major breakpoint region and 1 at the minor breakpoint region. High levels of BCL-2 orBAX expression occurred independently of t(14;18). There was no association between t(14;18) and either ploidy or proliferative activity. The inverse relationship between BCL-2 expression and proliferative activity in the intermediate- and high-grade NHLs is consistent with recent studies suggesting that Bcl-2 both retards entry into the cell cycle and inhibits apoptosis.

BCL-2 immunohistochemical evaluation in B-cell chronic lymphocytic leukemia and hairy cell leukemia before treatment with fludarabine and 2-chloro-deoxy-adenosine

Bcl-2 overexpression has been shown to be associated with several malignancies, including B-cell chronic lymphocytic leukemia (CLL) and non-Hodgkin's lymphomas (NHL), mainly low-grade and follicular in type. It has as yet not been described in hairy cell leukemia (HCL). In 30 patients with CLL and 14 with HCL who were consecutively selected for treatment with purine analogues (Fludarabine in CLL and 2-chloro-deoxy-adenosine in HCL), we evaluated bcl-2 oncoprotein expression in leukemic cells on marrow sections that were taken before treatment and stained immunohistochemically with a monoclonal antibody (Dakopatts 124 clone), by the avidin-biotin-peroxidase method. All samples were found to be bcl-2 positive, with a staining intensity that was moderate to strong in CLL and weak to moderate in HCL. 83% of CLL and 100% of HCL patients were responsive to purine analogues. These findings show that bcl-2 is overexpressed in almost all cases CLL and HCL and that bcl-2 overexpression does not predict a poor response to purine analogues, which are believed to induce apoptosis.

Rearrangements of bcl-6, bcl-2, c-myc and 6q deletion in B-diffuse large-cell lymphoma: clinical relevance in 71 patients

BACKGROUND

B-diffuse large-cell lymphomas (DLCL) have been associated with some molecular lesions, but the role of such lesions as prognostic markers is still controversial. This report concerns an investigation of the frequency and clinical correlation of bcl-6, bcl-2, c-myc rearrangements and 6(q) deletions in B-DLCL.

PATIENTS AND METHODS

The presence of these genetic lesions was analyzed in samples of lymph nodes or bone marrow collected at diagnosis in 71 patients with B-DLCL, all treated with an anthracycline-containing chemotherapy regimen.

RESULTS

Rearrangement of bcl-6 was found in 11 patients (15%), rearranged bcl-2 in 12 (17%), 6(q) deletions in 10 patients (14%) and c-myc rearrangement in four (6%). Patients with rearranged bcl-6 tended to have a more aggressive disease than patients with germ-line bcl-6 (intermediate-high/high risk according to IPI criteria: 73% vs. 43%), but there were no differences in three-year survival rates (62% vs. 42%) between the two groups. The numbers of involved extranodal sites were similar in patients with rearranged and those with germ-line bcl-6. Patients with bcl-2 rearrangement appeared to have a less aggressive disease than those with germ-line bcl-2 (low/ low-intermediate risk 75% vs. 47%) and a slightly better three-year survival rate (70% vs. 41%) but again the difference was not significant. Both groups with or without 6(q) deletion had similar clinical characteristics and outcomes. The four patients with c-myc rearrangement had aggressive disease and did poorly.

CONCLUSIONS

The analysis of molecular lesions in B-DLCL may be useful for a better diagnostic definition; however, in this study we were unable to show that the evaluated genetic lesions had a significant impact on clinical outcome.

Pathologic prognostic factors in diffuse aggressive non-Hodgkin's lymphoma

Recent advances in understanding the immunophenotypic, molecular genetic, and cytogenetic heterogeneity of diffuse large-cell lymphomas (DLCL) have provided new insights into the diversity of these disorders. Clinical prognostic factors are useful for predicting outcome in DLCL, but are surrogates of the underlying biology. The role of pathologic prognostic factors as the biologic correlates of clinical behavior in DLCL should allow the development of new prognostic models that incorporate both clinical and pathological data, and lead to improved outcome for those patients not cured by modern-day treatment regimens.

Prognostic Significance of Bcl-2 Protein Expression and Bcl-2 Gene Rearrangement in Diffuse Aggressive Non-Hodgkin's Lymphoma

The prognostic significance of Bcl-2 protein expression and bcl-2 gene rearrangement in diffuse large cell lymphomas (DLCL) is controversial. Bcl-2 protein expression prevents apoptosis and may have an important role in clinical drug resistance. The presence of a bcl-2 gene rearrangement in de novo DLCL suggests a possible follicle center cell origin and perhaps a distinct clinical behavior more akin to low-grade non-Hodgkin's lymphoma (NHL). The purpose of this study was to determine the impact of Bcl-2 protein expression and bcl-2 gene rearrangement (mbr and mcr) on survival of a cohort of patients with DLCL who were uniformly evaluated and treated with effective chemotherapy. Patients included the original MACOP-B cohort (n = 121) and the initial 18 patients treated with the VACOP-B regimen (total = 139). All patients had advanced-stage disease, were 16 to 70 years old, and corresponded to Working Formulation categories F, G, or H. No patients had prior treatment, discordant lymphoma, or human immunodeficiency virus seropositivity. Paraffin sections from diagnostic biopsies were analyzed for bcl-2 gene rearrangement including mbr and mcr breakpoints by polymerase chain reaction and Bcl-2 protein expression by immunohistochemistry. With a median follow-up of 81 months, overall (OS), disease-free (DFS), and relapse-free survival (RFS) were measured to determine the prognostic significance of these parameters. Analyzable DNA was present in 118 of 139 (85%) cases, with 14 demonstrating a bcl-2 rearrangement (11 mbr, 3 mcr). All 14 of these bcl-2 gene rearrangement-positive cases were found in the 102 patients with a B-cell immunophenotype, but the presence of this rearrangement had no significant influence on survival. Bcl-2 protein expression was interpretable in 116 of 139 (83%) cases, with immunopositivity detected in 54 of 116 (47%). Using a cut-off of greater than 10% Bcl-2 immunopositive tumor cells for analysis, positive Bcl-2 protein expression was seen in 28 of 116 (24%) patients and the presence of this expression correlated with decreased 8-year OS (34% v 60%, P &lt; .01), DFS (32% v 66%, P &lt; .001), and RFS (25% v 59%, P &lt; .001). Bcl-2 protein expression remained significant in multivariate analysis that included the clinical international prognostic index factors and immunophenotype (P &lt; .02). In conclusion, although bcl-2 gene rearrangement status could not be shown to have an impact on outcome, Bcl-2 protein expression is a strong significant predictor of OS, DFS, and RFS in DLCLs.

Prognostic Significance of Bcl-2 Protein Expression and Bcl-2 Gene Rearrangement in Diffuse Aggressive Non-Hodgkin's Lymphoma

The prognostic significance of Bcl-2 protein expression and bcl-2 gene rearrangement in diffuse large cell lymphomas (DLCL) is controversial. Bcl-2 protein expression prevents apoptosis and may have an important role in clinical drug resistance. The presence of a bcl-2 gene rearrangement in de novo DLCL suggests a possible follicle center cell origin and perhaps a distinct clinical behavior more akin to low-grade non-Hodgkin's lymphoma (NHL). The purpose of this study was to determine the impact of Bcl-2 protein expression and bcl-2 gene rearrangement (mbr and mcr) on survival of a cohort of patients with DLCL who were uniformly evaluated and treated with effective chemotherapy. Patients included the original MACOP-B cohort (n = 121) and the initial 18 patients treated with the VACOP-B regimen (total = 139). All patients had advanced-stage disease, were 16 to 70 years old, and corresponded to Working Formulation categories F, G, or H. No patients had prior treatment, discordant lymphoma, or human immunodeficiency virus seropositivity. Paraffin sections from diagnostic biopsies were analyzed for bcl-2 gene rearrangement including mbr and mcr breakpoints by polymerase chain reaction and Bcl-2 protein expression by immunohistochemistry. With a median follow-up of 81 months, overall (OS), disease-free (DFS), and relapse-free survival (RFS) were measured to determine the prognostic significance of these parameters. Analyzable DNA was present in 118 of 139 (85%) cases, with 14 demonstrating a bcl-2 rearrangement (11 mbr, 3 mcr). All 14 of these bcl-2 gene rearrangement-positive cases were found in the 102 patients with a B-cell immunophenotype, but the presence of this rearrangement had no significant influence on survival. Bcl-2 protein expression was interpretable in 116 of 139 (83%) cases, with immunopositivity detected in 54 of 116 (47%). Using a cut-off of greater than 10% Bcl-2 immunopositive tumor cells for analysis, positive Bcl-2 protein expression was seen in 28 of 116 (24%) patients and the presence of this expression correlated with decreased 8-year OS (34% v 60%, P < .01), DFS (32% v 66%, P < .001), and RFS (25% v 59%, P < .001). Bcl-2 protein expression remained significant in multivariate analysis that included the clinical international prognostic index factors and immunophenotype (P < .02). In conclusion, although bcl-2 gene rearrangement status could not be shown to have an impact on outcome, Bcl-2 protein expression is a strong significant predictor of OS, DFS, and RFS in DLCLs.

Relationship of p53, bcl-2, and Tumor Proliferation to Clinical Drug Resistance in Non-Hodgkin's Lymphomas

Although the cause(s) of clinical drug resistance in non-Hodgkin's lymphomas (NHL) is unknown, in vitro studies suggest that abnormalities of the p53 gene, bcl-2 overexpression, and low tumor proliferation rates may increase chemotherapy resistance. We analyzed tumor tissue from 75 patients with relapsed/refractory NHL (Working Formulation A through H) for p53 mutation/overexpression (abnormality), bcl-2 expression, and tumor proliferation and correlated them with multiple clinical characteristics, response to therapy, disease-free survival, and overall survival (OS). All tumor biopsy specimens were obtained within 6 weeks of treatment with EPOCH (infusional etoposide, vincristine, and doxorubicin and bolus prednisone and cyclophosphamide) chemotherapy. Overall, 16 (21%) tumors had a p53 abnormality. Of 13 tumors with overexpression, mutations were confirmed by sequence analysis in 11, and, in 44 tumors without overexpression, 3 showed mutations. A multivariate analysis showed that tumors with a p53 abnormality were more likely to be drug resistant than tumors with normal p53 (56% v 17%; P2 = .008) and to have a shorter median progression-free survival (PFS; 2.1 v 8.2 months; P2 = .008) and OS (11.7 v 21.5 months; P2 = .038), respectively. The presence of a p53 abnormality did not correlate with any clinical characteristic, bcl-2 expression, or tumor proliferation. A significant correlation was found between low tumor proliferation and drug resistance in a univariate (P2 &lt; .006) but not multivariate analysis. Patients with tumor proliferation of less than 80% were significantly more likely to have no response to therapy (31% v 6%) or to fail to achieve a complete response (16% v 44%) and tended to have shorter PFS and OS than did patients with higher proliferation. No significant association was found between bcl-2 expression and drug resistance, PFS or OS, although patients with intermediate-grade histologies and high bcl-2 expression tended to be drug resistant as compared with low level expressors (P2 &lt; .065). Of interest was the finding of a significant association between high bcl-2 and low tumor proliferation (P2 = .0045). In studies that have found an association between high bcl-2 expression and short PFS, bcl-2 may have been a surrogate for low tumor proliferation. Further studies are warranted to examine this question. These results suggest that p53 mutation and low tumor proliferation, but not bcl-2, may be important causes of clinical drug resistance in NHL.

Clinical significance of bcl-2 (MBR)/JH rearrangement in the peripheral blood of patients with diffuse large B-cell lymphomas

BACKGROUND

Approximately one-fourth of diffuse large B-cell lymphomas (DLCL) carry the bcl-2(MBR)/JH rearrangement caused by the t(14;18) translocation. The clinical significance of this rearrangement in patients with DLCL remains controversial. By polymerase chain reaction (PCR) we prospectively evaluated the prognostic relevance of the bcl-2 (MBR)/JH rearrangement present in circulating B-cells at the time of diagnosis.

MATERIALS AND METHODS

The bcl-2 (MBR)/JH rearrangement was analysed by a nested-PCR method in peripheral blood samples of 51 HIV-negative patients with previously untreated DLCL.

RESULTS

The bcl-2 (MBR)/JH rearrangement was detected in 16 cases (31%). Peripheral blood bcl-2 (MBR)/JH rearrangement detection by PCR at diagnosis was correlated with poor overall survival, lymphoma-specific survival and time to progression (log-rank P < 0.05). There was no statistically significant difference between the clinical characteristics at presentation of bcl-2/JH-positive and negative patients.

CONCLUSIONS

The peripheral blood is a readily accessible tissue for this type of analysis, and this study indicates that detection of the t(14;18) translocation at presentation in the blood of patients with DLCL may presage a poor prognosis.

Molecular heterogeneity of B-lineage diffuse large cell lymphoma

B-lineage diffuse large cell lymphoma (B-DLCL) arising de novo is characterized by a marked degree of clinical heterogeneity. To determine whether or not the clinical heterogeneity of de novo B-DLCL is reflected by heterogeneity in the molecular features of these tumors, we investigated the pattern of distribution of several genetic lesions in 70 cases of de novo B-DLCL at diagnosis. The panel of genetic lesions tested comprised the molecular alterations most frequently detected in B-DLCL, including rearrangements of BCL2, BCL6, and MYC as well as deletions of 6q and mutations of TP53. One or more genetic lesions were detected in 39/70 cases of B-DLCL. Isolated structural alterations of BCL2, BCL6, 6q or TPS3 were detected in 8/70, 10/70, 11/70, and 3/70 cases, respectively. No isolated MYC lesions were detected. Six cases carried different combinations of two genetic lesions, including lesions of BCL2 + BCL6 (1 case), BCL2 + MYC (1 case), BCL2 + 6q (2 cases), or BCL6 + 6q (2 cases). One case had accumulated three genetic lesions, namely a rearrangement of BCL2 and BCL6 and a mutation of TPS3. Overall, these data show that multiple distinct patterns of genetic lesions may associate with de novo B-DLCL, indicating that the molecular pathogenesis of this group of lymphomas is characterized by a high degree of molecular heterogeneity.

Optimal primer selection for clonality assessment by polymerase chain reaction analysis. III. Intermediate and high-grade B-cell neoplasms

Previous studies have reported that low-grade B-cell lymphoproliferative disorders have variable B-cell monoclonality detection rates by polymerase chain reaction (PCR) analysis. For instance, monoclonal B-cell populations from chronic lymphocytic leukemia/small lymphocytic leukemia and mantle cell lymphoma are most often readily amplified with a single primer pair, whereas follicular lymphomas and plasma cell neoplasms require alternative strategies to approach these higher diagnostic sensitivity standards. Because most published reports have not focused on the variation in PCR B-cell monoclonality detection among subtypes of intermediate and high-grade B-cell neoplasms, additional information is necessary to determine primer selection strategies and identify problematic tumor subtypes within this group. The current investigation, the third part in a series, was aimed at documenting the efficiency of B-cell monoclonality detection by PCR in 71 aggressive B-cell neoplasms of various types using a comprehensive approach. A predetermined panel of primer sets was used in an algorithmic fashion. Specifically, all samples were analyzed with the standard VH-FRIII/JH assay previously shown to have the highest efficiency of monoclonality detection within low-grade B-cell lymphoproliferative disorders. Negative samples were further evaluated with primer sets in the following order until a positive result was observed, or all primer sets were used: (1) bcl-2/JH, (2) VH-FRI family specific/JH, and (3) VH-FRI consensus/JH. Forty-three (61%) of the 71 B-cell neoplasms evaluated with VH-FRIII/JH showed monoclonal B-cell populations. Sequential use of the three reserve primer sets in samples negative with this initial primer pair resulted in an overall improvement in PCR detection from 61% to 82% (58 of 71 specimens) (P < .001). The VH-FRI family specific assay identified B-cell monoclonality in 11 (73%) of these 15 specimens and was the most productive reserve primer set. Individual categories exhibited the following initial (I) and final (F) PCR detection rates: acute lymphoblastic leukemia/lymphoblastic lymphoma, 11 specimens (I = 91% to F = 91%); small noncleaved cell lymphoma, 14 specimens (I = 79% to F = 86% [P > .25]); diffuse large cell lymphoma, 33 specimens (I = 52% to F= 85% [P < .005]) and large cell, immunoblastic lymphoma, 13 specimens (I = 38% to F = 62% [P < .01]). The authors have shown that comprehensive PCR analysis is capable of detecting B-cell monoclonality in a significant proportion of samples from each subtype of intermediate and high-grade B-cell neoplasm. The VH-FRIII/JH assay was an adequate initial primer set, but required augmentation with the reserve PCR assays to attenuate the false negative rate and improve diagnostic sensitivity. The B-cell clonality PCR assay is optimally used as a screening tool and when used in this fashion, the more laborious and time-consuming restriction fragment-Southern blot hybridization (RF-SBH) method for IgH gene rearrangement detection may be limited to a relatively small proportion of PCR-negative aggressive B-cell neoplasms.

Incidence and prognostic significance of t(14;18) translocation in follicle center cell lymphoma of low and high grade. A report from southern Sweden

BACKGROUND

The t(14;18)(q21;q32) is the most common recurrent genetic defect in follicle center cell lymphoma (FCC). Conflicting reports exist in regard to a possible prognostic significance for the translocation.

PATIENTS AND METHODS

In a single center, 102 patients with either low-grade (n = 50) or high-grade (n = 52) FCC (Kiel classification) and a median follow-up of 82 months were retrospectively studied to determine survival in relation to t(14;18) as shown by either PCR of the bcl-2 rearrangement in paraffinized tissue or karyotype analysis.

RESULTS

t(14;18) was detected in 30 of 50 (60%) low-grade FCC and in 12 of 52 (23%) high-grade FCC. The presence of the t(14;18) was not related to morphologic bone marrow involvement or other clinical parameters, but it was related to age: in low-grade FCC, patients with t(14;18) were an average of 17 years younger (p = 0.002) than those without the translocation. In the group with high-grade histology, 30% survived beyond 60 months regardless of t(14;18) status (p = 0.92). Patients with low-grade histology and t(14;18) fared better than those without, irrespective of age (p = 0.01). No significant difference in disease-free survival related to t(14;18) was found in either low- or high-grade FCC.

CONCLUSIONS

The incidence of t(14;18) is in accord with that of other European reports. T(14;18) does not define a prognostic subset of high-grade FCC, but is significantly correlated with a better survival in low-grade FCC. The association of t(14;18) with younger age and indolent lymphoma is perplexing in light of recent findings of an age-related increase in t(14;18) in normal subjects.

Bcl-2 oncoprotein is widespread in lymphoid tissue and lymphomas but its differential expression in benign versus malignant follicles and monocytoid B-cell proliferations is of diagnostic value

The distribution of Bcl-2 oncoprotein was studied immunohistochemically in formaldehyde-fixed and paraffin-embedded reactive and neoplastic lymphoid tissue. The potential of Bcl-2 for the differential diagnosis of follicular lesions was emphasized, and the results on follicular lesions were correlated with those of polymerase chain reaction (PCR) assay of the immunoglobulin heavy chain gene rearrangement. In hyperplastic lymphoid tissue, Bcl-2 reactivity was widespread, including germinal center surroundings, scattered cells within the germinal centers, and the T-cell areas in general. Distinctively negative lymphoid populations included the majority of germinal center cells, and the negative staining pattern was maintained in cases of florid hyperplasia. In contrast, follicular lymphoma cells were consistently Bcl-2 positive. The immunohistochemical Bcl-2 reactivity of lymphoma follicles correlated with the clonal PCR amplification pattern of the immunoglobulin heavy chain gene; all Bcl-2-negative hyperplasias revealed a non-clonal pattern. Clusters of monocytoid B cells were Bcl-2 negative, whereas monocytoid B-cell lymphomas and closely related MALT lymphomas were positive. All other small cell non-Hodgkin's lymphomas of B-cell types showed nearly uniform Bcl-2 reactivity, whereas large cell B-cell lymphomas were variably positive (74%). In Hodgkin's cells, Bcl-2 reactivity was seen in the neoplastic populations of most cases of nodular sclerosis and mixed cellularity types, whereas the L&H and Reed-Sternberg cells in lymphocyte predominance Hodgkin's disease were negative in most cases. Bcl-2 immunohistochemistry thus appears very valuable in the differential diagnosis of follicular hyperplasia and neoplasia, and it may help to distinguish between reactive and neoplastic monocytoid B cells. However, Bcl-2 immunohistochemistry is not useful in the subtyping of B-cell lymphomas.