Hepatitis C virus and lymphoma

Hepatitis C virus (HCV) is well known for its aetiological role in chronic non-A, non-B viral hepatitis, liver cirrhosis and hepatocellular carcinoma; in addition, the virus has also been implicated in a number of extra-hepatic "autoimmune" disease manifestations. A causative association between HCV and non-Hodgkin lymphoma (NHL) was postulated relatively recently and has been the subject of intense investigation, as well as some debate. On the strength of epidemiological data, emerging biological investigations and clinical observations, HCV appears to be involved in the pathogenesis of at least a proportion of patients with NHL. Morphologically, HCV-associated lymphomas represent a variety of histological subtypes including marginal zone lymphoma (splenic, nodal and extranodal), small lymphocytic lymphoma/chronic lymphocytic leukaemia, lymphoplasmacytic lymphoma and diffuse large B-cell lymphoma. Remarkably, some HCV-associated NHL appears to be highly responsive to antiviral therapy, providing some clinical evidence for this relationship, as well as the prospect for novel therapeutic intervention.

Rapid detection of leukemia-associated translocation fusion genes using a novel combined RT-PCR and flow cytometric method

Efficient detection of recurrent translocation-associated fusion genes is of critical importance for the diagnosis, prognosis and post-therapeutic monitoring of many leukemias. Typically, the presence of such translocations is revealed by RT-PCR technique, followed by Southern blot hybridization to ensure specificity of the PCR product. Though widely employed, post-PCR analysis of this type is relatively laborious and time-intensive. As a departure from standard analytic approaches, we have developed a robust novel method combining both high specificity and sensitivity, based on polystyrene bead capture of fluorescently labeled PCR products, with subsequent analysis by flow cytometry. Results from cell line and patient sample evaluations indicate that this method may be easily incorporated into the diagnostic molecular laboratory as a rapid and cost-effective alternative to currently employed techniques.

Detection of t(15;17)(q24;q21), inv(16)/t(16;16)(p13;q22), and t(8;21)(q22;q22) Anomalies in Acute Myeloid Leukemias

The acute myeloid leukemias (AMLs) are a relatively heterogeneous group of diseases. However, there is growing awareness that the clinical features and subclassification of morphologic leukemia types is often highly correlated with tumor genetics. Furthermore, distinct genetic subgroups of AML are associated with improved therapeutic sensitivity and a more favorable clinical outcome. These observations have prompted suggestions for a revision of the current French-American-British leukemia classification (1), utilizing genetically defined principles (2). Three recurrent chromosomal translocations are identified in approx 25-30% of de novo adult AMLs. These include the t(15;17), associated with acute promyelocytic leukemia ([APL]; AML-M3); the inv(16) and related t(16;16), associated with AML-M4Eo; and the t(8;21), associated most commonly with AML-M2. Each of these abnormalities results in the formation of a chimeric leukemia-specific fusion gene, which is transcribed and expressed as a fusion protein. The widespread genetic deregulation caused by such fusion proteins is thought to interfere with proliferative control and cell differentiation mechanisms, leading to the leukemic state. The presence of these and other fusion gene events can be specifically and sensitively detected by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis.

Comparison of capillary electrophoresis and polyacrylamide gel electrophoresis for the evaluation of T and B cell clonality by polymerase chain reaction

Polymerase chain reaction (PCR) technique is widely used in the diagnosis of lymphoma, and PCR amplification products are typically detected by polyacrylamide gel electrophoresis (PAGE). However, the identification of small clonal populations, or the distinction of clonal PCR products in a polyclonal milieu remains difficult, requiring technically demanding alterations to gel analysis. This study describes an alternative approach using a capillary electrophoresis (CE) system to produce an accurately sized electropherogram. A variety of patient samples were examined, including solid tissue, peripheral blood, bone marrow aspirates, and paraffin-embedded tissue. A total of 28 samples were evaluated by PCR for B-cell clonality by detection of immunoglobulin heavy chain gene rearrangement and 29 samples for T-cell clonality by detection of T-cell gamma locus gene rearrangement. Standard 10% PAGE analysis of PCR products was compared with CE. There was a 100% concordance in the assessment of both B-cell and T-cell clonality. Dilution studies with the SUP-B15 cell line showed a detection limit of 0.03% for B-cell clonality and 0.05% for T-cell clonality using CE, versus 0.2% to 1%, respectively for PAGE. Automated, fluorescent analysis of PCR products by CE seems to be at least equally as effective as gel-based analysis for the detection of clonal B-cell and T-cell populations. Moreover. CE offers superior resolution and improved sensitivity, thus representing a significant improvement over traditional gel electrophoretic techniques in these regards.

Blastic mantle cell leukemia: an unusual presentation of blastic mantle cell lymphoma

Six patients had blood and bone marrow manifestations characterized by the presence of morphologically immature or blastic B-lineage lymphoid cells expressing CD5 antigen. The median patient age was 70 years, and the male-to-female ratio was 5:1. The presence or degree of lymphadenopathy and splenomegaly was variable among this group at staging evaluation, although two patients did not have these features. One patient had an antecedent diagnosis of classical nodal mantle cell lymphoma, without prior morphologic blood or bone marrow involvement. Other patients lacked a history of underlying lymphoproliferative disorders. The median white blood cell count was 120 x 10(9)/L. Most patients had thrombocytopenia, whereas only one patient had neutropenia at presentation. Leukemic peripheral blood cells in these six cases were small to medium in size with fine or granular nuclear chromatin and small or inconspicuous nucleoli. The pattern of marrow involvement was interstitial or diffuse, with cells showing immature nuclear features resembling acute leukemia or blastic lymphoma. All tumors demonstrated a consistent immunophenotype of B-cell lineage, surface immunoglobulin positivity, and CD5 antigen expression. The progenitor cell-associated markers CD34 and TdT were not expressed, and CD23 antigen was either negative (three of four cases) or only weakly present (one of four cases). The presence of a karyotypic t(11;14)(q13;q32) was documented in one tumor, whereas two other cases had BCL-1 gene rearrangements by either polymerase chain reaction or Southern blot analysis. Cyclin D1 mRNA overexpression was noted in three of four cases tested. This patient group was characterized by very poor overall survival (median, 3 months; range, 0.5 to 6 months). The aggregate clinical, pathologic, and genetic data in these unusual cases are consistent with de novo or predominant leukemic presentations of blastic mantle cell lymphoma. Accurate diagnosis in such cases is greatly facilitated by cytogenetic studies or the demonstration of BCL-1/cyclin D1 abnormalities.

Molecular diagnosis in pediatric acute leukemias

This article summarizes the tremendous progress currently achieved in understanding the molecular basis of the pediatric acute leukemias. The article is organized from the perspective of the most frequently encountered pediatric acute leukemia genetic abnormalities in a molecular diagnostics laboratory setting. For each specific entity, the basic molecular biology, putative mechanisms of leukemogenesis, detection methods, and clinical significance are reviewed. Emphasis is placed on discussing the fusion genes generated from common nonrandom chromosomal translocations in B-lineage acute lymphoblastic leukemia (ALL), although brief summaries of T-lineage and myeloid leukemia, as well as the use of the antigen receptor gene rearrangement for residual disease monitoring in acute lympocytic leukemia are also presented. Finally, an overview of emerging technologies of potential importance in the laboratory diagnosis and evaluation of the pediatric acute leukemias is provided.

Molecular analysis and clinical outcome of adult APL patients with the type V PML-RARalpha isoform: results from intergroup protocol 0129

The type V (for variable) promyelocytic leukemia retinoic acid receptor (PML-RAR)alpha transcript, found in approximately 8% of adult patients with acute promyelocytic leukemia (APL), is defined molecularly by truncation of PML exon 6 and frequent insertion of genetic material from RARalpha intron 2. To more fully characterize the molecular features of PML-RARalpha V-type transcripts and to determine whether V-form APL patients have a distinct clinical presentation or prognosis, we analyzed 18 adult V-form APL patients enrolled on Intergroup protocol 0129 (INT-0129). Truncations in PML exon 6 ranged from 8 to 146 nucleotides, and 3 to 127 extra nucleotides (1 to 42 extra amino acids) were inserted at the PML exon 6/RARalpha exon 3 junction in 13 cases. No distinguishing morphologic, cytogenetic, or immunophenotypic features of V-form blasts were identified. A total of 5 of 7 patients induced with ATRA and 8 of 11 patients who received chemotherapy for induction achieved complete remission (CR). Six patients have relapsed, 4 after chemotherapy induction and 2 after ATRA. Nine patients (50%) are alive, 6 in continuous CR, 2 after salvage therapy for relapsed or refractory disease, and 1 after alternative treatment following early removal from protocol. Although the failure rate for V-form APL patients was high (61%), the low power of the current study to detect clinically significant differences precludes a meaningful comparison of clinical outcomes between the 18 V-form cases and non-V-form adult APL patients enrolled on INT-0129. (Blood. 2000;95:398-403)

Primary non-Hodgkin's lymphoma and malakoplakia of the vagina: a case report

The vagina is a rare site for both primary non-Hodgkin's lymphoma and malakoplakia. We report a case of concurrent diffuse large B-cell lymphoma and malakoplakia of the vagina in a 67-year-old woman presenting with a vaginal discharge and a vaginal mass. The patient had two biopsy specimens reported as showing malakoplakia only, followed by a third biopsy specimen 10 months later which was diagnosed as diffuse large B-cell lymphoma. Review of the first two biopsy specimens showed areas of histiocytes with Michaelis-Gutman bodies merging with areas of cells with slightly larger nuclei and more amphophilic cytoplasm. Immunohistochemistry for the B-cell marker L-26 (CD20) and polymerase chain reaction analysis of the immunoglobulin heavy chain gene were helpful in retrospectively distinguishing the population of diffuse large B-cell lymphoma from the areas of malakoplakia. The third biopsy specimen showed sheets of large atypical lymphoid cells characteristic of a large cell lymphoma. Malakoplakia has been described in association with a variety of cancers, and this is only the second report of malakoplakia associated with non-Hodgkin's lymphoma. Considering the rarity of these two entities in the vagina, it is unlikely that the association in this case is coincidental, raising the possibilities of an unusual reaction to the presence of lymphoma or a common pathogenesis such as underlying chronic inflammation. Epstein-Barr virus DNA was detected in the second biopsy specimen, suggesting a possible role in the pathogenesis of this lymphoma.

Prognostic significance of anaplastic lymphoma kinase (ALK) protein expression in adults with anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) is an aggressive lymphoma that is frequently associated with the t(2;5)(p23;q35), resulting in expression of a fusion protein, nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), which can be detected by either monoclonal or polyclonal antibodies to the ALK protein. The clinical features of adults with ALCL are incompletely described, and the prognostic factors that are useful for predicting survival remain unclear. This report describes the clinical and laboratory findings in 70 adults with systemic ALCL who were treated with curative intent. We attempted to identify the clinical and pathological factors of prognostic importance, including the International Prognostic Index (IPI), immunophenotype, and expression of the ALK protein. The median age of the patients was 49 years (range, 15 to 75). There were 26 women and 44 men with a median follow-up of 50 months for living patients. Advanced stage was present in 56% and B symptoms were noted in 70% of the patients. Immunostains showed that 46% of the cases had a T-cell phenotype, 36% a null phenotype, and 18% a B-cell phenotype. The expression of ALK protein was found in 51% of the cases. The IPI factors were evenly distributed between the ALK+ and ALK- groups, except that the ALK+ patients were younger (median age, 30 v 61 years; P <.002). The ALK+ cohort included cases with null (44%), T-cell (42%), and B-cell (14%) phenotypes. All 10 cases with cytogenetic or molecular evidence of a t(2;5) were ALK+. The 5-year overall survival (OS) of the entire cohort was 65%. The 5-year OS of the ALK+ and ALK- cases was 79% and 46%, respectively (P <.0003). Analysis of only the T-cell/null cases (n = 57) showed a 5-year OS of 93% for the ALK+ cases and only 37% for the ALK- cases (P <.00001). Univariate analysis of the clinical features showed that age </=60 years (P <.007), a normal serum lactate dehydrogenase (LDH) (P <.00001), a good performance status (Eastern Cooperative Oncology Group [ECOG] <2) (P <.03), </=1 extranodal site of disease (P <.012), and an IPI score </=3 (P <.00001) were associated with improved OS. Although a younger age correlated with ALK positivity, multivariate analysis showed that only a normal serum LDH (P <. 00001), an IPI score of </=3 (P <.0005), and ALK protein expression (P <.005) predicted independently for an improved OS. We conclude that ALCL is a heterogeneous disorder. However, ALK protein expression is an independent predictor of survival and serves as a useful biologic marker of a specific disease entity within the spectrum of ALCL.

Concurrent chromosomal alterations at 3q27, 8q24 and 18q21 in B-cell lymphomas

Recurrent chromosomal translocations in malignant lymphomas most commonly involve 18q21(bcl-2), 8q24 (c-myc) and 3q27 (bcl-6), with an incidence of 27%, 11% and 6%, respectively. Individual cases concurrently harbouring two of these three rearrangements have been previously reported. This report describes four patients with cytogenetic alterations affecting all three loci, which was confirmed by molecular analysis in one case. Clinically, each patient had aggressive B-cell lymphoma with disseminated disease often involving the central nervous system, poor response to chemotherapy and short survival. Activation of c-myc in association with deregulation of bcl-2, bcl-6 or both confers high-grade disease with a poor prognosis.

Primary follicular lymphoma of the testis in childhood

BACKGROUND

Follicular lymphoma in childhood is rare. The authors present four unusual primary follicular lymphomas of the testis in children.

METHODS

Tumor tissue was evaluated using light microscopy, immunohistochemistry, flow cytometry, and polymerase chain reaction (PCR) for immunoglobulin heavy chain (IgH) and bcl-2 gene rearrangements. Southern blot and immunohistochemical analyses were used to detect bcl-6 gene rearrangements and protein expression, respectively.

RESULTS

Four young boys ranging in age from 3 to 10 years were diagnosed with Stage IE follicular large cell lymphoma (Grade 3). A B-cell phenotype was documented in all four cases; monoclonality was confirmed in three cases by demonstration of light chain restriction or clonal IgH gene rearrangement. None of the lymphomas expressed Bcl-2 or p53 protein, and bcl-2 gene rearrangements were not found in the three lymphomas studied. In contrast, Bcl-6 protein was expressed by all three lymphomas studied, and a bcl-6 gene rearrangement was detected in the one case analyzed by Southern blot. All four boys were treated by orchiectomy and combination chemotherapy and are alive with no evidence of disease 18-44 months following their initial diagnoses.

CONCLUSIONS

Follicular lymphomas may rarely occur as primary testicular tumors in prepubertal boys and, when localized, appear to be associated with a favorable prognosis. In contrast to follicular lymphoma in adults, pediatric follicular lymphomas of the testis are usually of large cell type (Grade 3) and lack bcl-2 or p53 abnormalities. The identification, in one case, of a bcl-6 gene rearrangement suggests an alternate molecular pathogenesis for pediatric follicular lymphoma.

Incidence of second neoplasms in patients with MALT lymphoma: no increase in risk above the background population

BACKGROUND

Lymphomas of mucosa associated lymphoid tissue (MALT) are a special type of extranodal lymphoma, possibly related to chronic antigenic stimulation. Increased cancer susceptibility may also contribute to the development of MALT lymphoma (MALToma). It has been suggested that patients with MALToma have an increased incidence of other malignancies.

PATIENTS AND METHODS

We retrospectively reviewed the histology and clinical records of 147 patients with MALToma, including 51 cases of gastric MALToma. The incidence of any second malignancy was confirmed with a provincial registry. The relative rates of cancer, excluding MALToma, were calculated relative to the background population of the same age group and secular year.

RESULTS

A total of 41 tumors occurred in 32 patients (21%), including 22 solid tumors. The incidence of solid tumors in the gastric MALToma group was 15%. Seven patients had two or more second malignancies. Cancer occurred before diagnosis of MALToma in 29 cases, concurrent with MALToma in three, and after MALToma in nine. Follow-up of the surviving patients is short (median 17.6 months). The relative rate from birth of a second malignancy was 0.86 in the whole group (90% confidence interval (CI): 0.62-1.16) and 0.95 (90% CI: 0.55-1.54) in the gastric MALToma group. The rates were roughly the same if skin cancers were excluded.

CONCLUSIONS

The incidence of second cancers in this series is similar to previous reports. However, when compared to an age-matched population followed for the same period of time, MALToma patients do not appear to have a statistically significant increased rate of cancers.

The presence of CD34+ cell clusters predicts impending relapse in children with acute lymphoblastic leukemia receiving maintenance chemotherapy

Early detection of relapse in children with acute lymphoblastic leukemia (ALL), as well as distinction of leukemic blasts from hematogones, can be difficult by morphologic examination alone. Using CD34 and terminal deoxynucleotidyl transferase (TdT) immunoperoxidase stains, we studied specimens from 25 children with ALL in morphologic remission to determine if we could identify children at risk of relapse. We studied morphologic remission bone marrow specimens from 9 patients who experienced relapse during the subsequent 6 months and 16 children who remained in complete remission, including 10 specimens with increased numbers of hematogones. Despite morphologic remission, clusters of more than 5 CD34+ and/or TdT-positive cells were identified before overt relapse in 6 of 9 cases of relapse, but were noted in only 1 of 10 specimens from children in continuous complete remission and none of 10 specimens with increased numbers of hematogones. Clusters of CD34+ or TdT-positive cells can identify individual patients at risk for imminent relapse. Hematogones may be differentiated from lymphoblasts by this method.

Characterization and use of an antibody detecting the CBFbeta-SMMHC fusion protein in inv(16)/t(16;16)-associated acute myeloid leukemias

The inv(16)(p13q22) and t(16;16)(p13;q22) cytogenetic abnormalities occur commonly in acute myeloid leukemia (AML), typically associated with French-American-British (FAB) AML-M4Eo subtype. Reverse transcriptase-polymerase chain reaction (RT-PCR) techniques have been recently developed to detect the presence of several variants of the resultant CBFB-MYH11 fusion gene that encodes a CBFbeta-smooth muscle myosin heavy chain (SMMHC) fusion protein. We have now determined the clinical use of a polyclonal antibody [anti-inv(16) Ab] directed against a junctional epitope of the most common type of CBFbeta-SMMHC fusion protein (type A), which is present in 90% of inv(16)/t(16;16) AML cases. Using flow cytometry, reproducible methods were developed for detection of CBFbeta-SMMHC proteins in permeabilized cells; flow cytometric results were then correlated with cytogenetics and RT-PCR detection methods. In an analysis of 42 leukemia cases with various cytogenetic abnormalities and several normal controls, the anti-inv(16) Ab specifically detected all 23 cases that were cytogenetically positive for inv(16) or t(16;16), including a single AML case that was RT-PCR-negative. In addition to detecting all type A fusions, the anti-inv(16) Ab also unexpectedly identified the type C and type D CBFbeta-SMMHC fusion proteins. Molecular characterization of one RT-PCR-positive and Ab-positive t(16;16) case with a non-type A product showed a novel previously unreported CBFB-MYH11 fusion (CBFB nt 455-MYH11 nt 1893). Flow cytometric results were analyzed using the Kolmogorov-Smirnov statistic D-value and the median value for positive samples was 0.65 (range, 0.35 to 0.77) versus 0.07 (range, -0.21 to 0.18) in the negative group (P < .0001). The overall concordance between cytogenetics and RT-PCR was 97%, whereas the concordance between flow cytometry and cytogenetics was 100%. Thus, using the anti-inv(16) Ab, all cytogenetically positive and RT-PCR-positive AML cases with inv(16) or t(16;16) could be rapidly identified. This study demonstrates the use of this antibody as an investigational tool in inv(16)/t(16;16) AML and suggests that the development of such reagents may have potential clinical diagnostic use.