Bone marrow involvement in Burkitt's lymphoma and its relationship to acute B-cell leukemia

Towards curative therapy in burkitt lymphoma: the role of early african studies in demonstrating the value of combination therapy and CNS prophylaxis

This paper describes the treatment of Burkitt lymphoma (BL) from the time of its discovery in Africa up to the present. Pioneer investigators explored the value of chemotherapy since surgery and radiation were not effective modalities. Complete response was observed with many drugs used as single agents, but Ziegler and colleagues showed that patients resistant to one drug could achieve cure and potentially long-term survival with other drugs. Subsequently, a combination of cyclophosphamide (CTX), vincristine (VCR), and methotrexate (MTX) was shown to be active, but a survival advantage compared to CTX alone could not be demonstrated because effective CNS prophylactic therapy, in the form of intrathecal therapy, was not given. A recent re-evaluation of this regimen in Africa with multiple doses of intrathecal therapy compares favourably with recent studies of single agent CTX, and other drugs have been shown to be non-cross resistant. Optimal results for patients with extensive disease probably require 5 or 6 effective drugs along with intrathecal therapy, using MTX and Ara-C. In Africa, doses must be lower, because of limitations in supportive care, but in technically advanced countries cure rates in excess of 90% can be obtained. Rituximab may improve the results in some patient groups and allow less intensive therapy without a reduction in survival in others.

Treatment of Burkitt lymphoma in children and adults: Lessons from Africa

Modern chemotherapy for childhood Burkitt lymphoma has its origins in Africa, where treatment evolved from one or two doses of single agents, which were curative in some patients, to combinations of non-cross-resistant drugs. Subsequently, in Europe and the United States, high-dose methotrexate, high-dose cytarabine, etoposide, and ifosfamide were found to be active in children with recurrent disease and were incorporated into primary therapy for patients with high-risk disease. These third-generation protocols produce overall cure rates around 90%. Therapy regimens for adults with Burkitt lymphoma have been developed by modifying second-generation pediatric protocols, and few investigators have used the third-generation pediatric regimens that include higher doses of methotrexate and additional agents. The weight of evidence strongly suggests that high-dose therapy with stem cell rescue in first remission cannot substitute for intensive therapy from the outset. Tolerance of intensive regimens by the elderly is a legitimate concern, but it seems appropriate to modify therapy only when necessary in individual patients. The value of rituximab and granulocyte colony-stimulating factor in patients undergoing intensive therapy (particularly the elderly) is worthy of further exploration. Because childhood diffuse large-B-cell leukemia (DLBCL) responds equally well to therapy for Burkitt lymphoma, more intensive therapy and intensive support might also give better results in at least a subset of adults with advanced DLBCL-perhaps defined on the basis of limited molecular profiling, which has provided new information about the categories of aggressive B-cell lymphomas.

IGH and IGK gene rearrangements as PCR targets for pediatric Burkitt's lymphoma and mature B-ALL MRD analysis

We recently reported that minimal residual disease (MRD) and minimal disseminated disease (MDD), assessed by long-distance PCR (LD-PCR) for t(8;14), are negative prognostic factors in mature B-cell acute lymphoblastic leukemia (B-ALL) and in Burkitt's lymphoma (BL). However, t(8;14) is detectable in only about 70% of patients, thus preventing MRD studies by this approach in the remaining patients. At present, no molecular assays have been reported for MRD and MDD analysis in t(8;14)-negative patients. The aim of our study was to evaluate the characteristics of patient-specific immunoglobulin (Ig) gene rearrangements as RQ-PCR targets for MRD analysis, in order to extend MRD studies to those patients who are not eligible for the LD-PCR assay. The study was performed according to the guidelines of the European Study Group on MRD detection in ALL (ESG-MRD-ALL). Overall, 36 B-ALL and 19 BL cases were analyzed. Multiple PCR reactions were performed for each sample to identify heavy and kappa light-chain rearrangements. A total of 97 RQ-PCR targets (62 for B-ALL, 35 for BL) were analyzed for sensitivity. The rearrangement pattern identified was similar to that reported for normal peripheral blood lymphocytes. In 88% of the targets, a sensitivity of at least 10(-4) was achieved. In 87% of patients (84% of B-ALLs, 95% of BLs) at least one sensitive target was available. All PCR targets identified at diagnosis were preserved at relapse. Our results suggest that MDD and MRD can be successfully studied using a single sensitive Ig target in the great majority of B-ALL and BL cases. The combination of LD-PCR and Ig-based assays will allow MRD analysis in virtually all of the patients.

Prognostic role of minimal residual disease in mature B-cell acute lymphoblastic leukemia of childhood

PURPOSE

To study the prevalence of t(8;14) at diagnosis and the response kinetics to treatment of minimal residual disease (MRD) in B-cell acute lymphoblastic leukemia (B-ALL) patients and determine its impact on prognosis.

PATIENTS AND METHODS

A total of 68 children affected by de novo B-ALL enrolled onto the Berlin-Frankfurt-Muenster-based Italian Association of Pediatric Hematology and Oncology LNH-97 clinical protocol were studied. Bone marrow aspirate from each patient was analyzed for the presence of t(8;14)(q24;q32) by long-distance polymerase chain reaction at diagnosis, after the first chemotherapy cycle, and after subsequent cycles until negative for MRD. Morphologic and immunophenotypic analyses were reviewed centrally.

RESULTS

A total of 47 patients (69%) were positive for t(8;14)(q24;q32). MRD response kinetics was determined in 39 patients. All of them reached clinical complete remission and most (31 of 39) became MRD negative after the first chemotherapy cycle. The 3-year relapse-free survival (RFS) was 38% (SE = 17%) in patients MRD positive after the first chemotherapy cycle compared with 84% (SE = 7%) in MRD-negative patients (P = .0005), whereas there was no difference in RFS for children who reached a clinical complete remission after the first chemotherapy cycle versus those who did not (RFS = 72% and SE = 9%; RFS = 79% and SE = 11%, respectively; P = .8). In multivariate analysis, MRD was shown to be predictive of higher risk of failure.

CONCLUSION

Our study demonstrated that MRD carries a negative prognostic impact in B-ALL patients and suggests that a better risk-adapted therapy, possibly including the use of anti-CD20 monoclonal antibody, should be considered in selected patients.

Bone marrow involvement in young patients with non-Hodgkin's lymphoma: the importance of multiple bone marrow samples for accurate staging

Of 95 young patients with non-Hodgkin's lymphoma treated at the National Cancer Institute on Pediatric Branch Protocol 7704, 18 (18.9%) had bone marrow involvement prior to treatment. Their mean age was 20.5 years. Twelve patients had small, non-cleaved lymphoma (ten Burkitt's and two undifferentiated, unspecified), five had lymphoblastic lymphoma, and one had a diffuse large cell lymphoma. All had extensive disease. We obtained bilateral bone marrow biopsy specimens, touch preparations, clot sections, and aspirate smears from 13 of the 18 patients. When paired contralateral samples were reviewed, in as many as six out of ten of the pairs only one side was positive for tumor. When paired ipsilateral samples were similarly reviewed, in as many as seven out of 21 of the pairs only one specimen was positive for tumor. The biopsy specimen was the most useful of the four types of study performed, yielding positive results in 87% of the preparations. Thus, in a high percentage of patients, multiple marrow sampling revealed disease that might have been missed if fewer specimens had been obtained. Only four of our 18 patients (22.2%) had long-term remissions. Because young patients with marrow disease are at high risk and may be eligible for more intensive treatment protocols, we recommend that staging should include bilateral bone marrow biopsies and bilateral aspirates.

Occurrence of t(8;22)(q24.1;q11.2) involving the MYC locus in a case of pediatric acute lymphoblastic leukemia with a precursor B cell immunophenotype

The authors describe a child with clinical presentation of acute leukemia and an immunophenotype consistent with precursor B-cell acute lymphoblastic leukemia. However, the lymphoblasts had atypical L3 features and the chromosome rearrangement t(8;22)(q24.1;q11.2) involving the MYC locus. The cytogenetic features in this patient were characteristic of mature B/Burkitt leukemia and led to modulation of therapy. This case highlights the need for timely cytogenetic and molecular studies in the diagnosis of acute leukemia.

A role for secondary V(D)J recombination in oncogenic chromosomal translocations?

Chromosomal translocations are hallmarks of certain lymphoproliferative disorders. Indeed, in many leukemias and lymphomas, translocations are the transforming event that brings about malignancy. Recurrence of the immunoglobulin (Ig) and T-cell receptor (Tcr) loci at the breakpoints of oncogenic chromosomal translocations has led to speculation that the lymphocyte-specific process of V(D)J rearrangement, which is necessary for the generation of functional Ig and TCR antigen receptors on B and T lymphocytes, mediates translocation. Recent studies have led to a fuller understanding of the molecular mechanisms of V(D)J rearrangement and have revealed that the V(D)J recombinase possesses latent transposase activity. These studies have led to plausible models of illegitimate V(D)J recombination producing chromosomal translocations consistent with those present in lymphomas and leukemias. Errors of V(D)J recombination may even generate lymphomas with the phenotypes of mature cells. For example, follicular and Burkitt's lymphomas have been classified by phenotype and somatic genotype as malignant germinal center (GC) B or post-GC B cells. The GC is a site of affinity maturation where B cells undergo V(D)J hypermutation and Ig class switch; in addition, much evidence has accumulated to suggest that GC B cells may also support secondary V(D)J recombination. Interestingly, all three of these elements, genomic plasticity, mutation, and translocation breakpoints near switch sites or recombinational elements, are characteristic of certain lymphomas. The high frequency of lymphomas carrying these GC markers suggests that the GC reaction may play a significant role in lymphomagenesis.

Variant translocations in sporadic Burkitt's lymphoma detected in fresh tumour material: analysis of three cases

Burkitt's lymphoma/Burkitt cell leukaemia (BL) is characterized by one of the reciprocal translocations involving the MYC oncogene on chromosome 8 and one of the immunoglobulin (Ig) loci on chromosomes 14, 2 or 22. In the few cell lines with the variant translocations t(2;8) and t(8;22) reported to date, the breakpoints on chromosome 8 were located downstream of MYC at a distance of up to 300 kb and more. Here, we describe three new cases with variant translocations. Fresh tumour material from paediatric patients, negative for the common translocation t(8;14), was analysed using a long-distance (LD) polymerase chain reaction (PCR) approach. On chromosome 8, primers were derived from several different regions 3' of MYC, and on chromosomes 2 and 22 from the constant regions of the Ig kappa (Igkappa) and lambda (Iglambda) genes. One translocation t(2;8) and two t(8;22) were detected. In the t(2;8) translocation, the chromosome 8 breakpoint was located 2 kb 3' of the MYC exon 3 and the chromosome 2 breakpoint within an unrearranged Igkappa locus. The breakpoints of the two translocations t(8;22) were detected 16 kb for one and 58 kb for the other downstream of MYC. Sequencing the t(8;22) translocation in one of the cases showed hypermutation of the translocated variable Vlambda4b gene. The presence of hypermutated variable regions in the t(8;22) case suggests germinal centre B cells as the origin of this translocation. The t(2;8) translocation is the first description of a translocation t(2;8) involving an unrearranged Igkappa gene. A mechanism different from V-J recombination and somatic hypermutation has to be proposed for this translocation.

Management of histologically aggressive lymphomas with a high risk of CNS disease

The NHLs are a group of neoplasms that share a common target tissue, and are characterized by a high degree of biological and clinical heterogeneity. Adult lymphomas with a high propensity for CNS involvement comprise SNCC, lymphoma (ATLL), LL, and PCL of immunocompromised patients. Despite recently reported encouraging results, there is no standard therapy available for ATLL or PCL. In contrast, recent data from several groups suggest that the therapeutic outcome of SNCC lymphoma in adults is similar to the excellent results in children, when the same regimens are used, and the toxicity, at least for adults less than 60 years, is also similar. Although more intensive chemotherapy combined with CNS prophylaxis has extended the long-term survival of patients with LL, the treatment results in adults fall short of those for children.

Acute lymphoblastic leukemia. A comprehensive review with emphasis on biology and therapy

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. It is now curable in 60-70% of children. Most of the current understanding of the biology and treatment of ALL originates from studies of children. In adults, although much progress has been achieved, ALL is curable in only 20-35% of patients.

METHODS

A review of the biology and treatment of ALL from the English literature was performed.

RESULTS

Immunophenotypic and cytogenetic analyses of ALL have contributed to a more rational classification of ALL. These analyses have identified subgroups with poor prognosis or with different therapeutic requirements. Overall, 60-70% of adults with ALL have poor prognostic features, including older age, a high leukocyte count, non-T-cell immunophenotype, Ph-positive genotype, and longer time to achieve a complete remission. These patients have a cure rate of 20-25%, whereas those without these risk factors, have a 60-70% probability of survival. The use of more intensive induction regimens with growth factor support may improve survival rates. Also, intensive consolidation-intensification may improve survival rates. Most patients benefit from maintenance therapy, but the dose schedule must be optimized. Central nervous system (CNS) prophylaxis is beneficial, particularly for patients with a high risk for CNS relapse and when introduced early during induction of remission. Patients with high risk characteristics may benefit from allogeneic bone marrow transplantation (BMT) during first remission, and all other patients may benefit from it during first or subsequent relapse. Autologous BMT may be a valuable option for poor compliant patients.

CONCLUSIONS

Although the prognosis of patients with ALL has improved markedly during the past decades, newer strategies, including more dose-intensive therapy, the search for new drugs, and more target-specific therapy, are needed to improve the current cure rates.

Aggressive chemotherapy in the treatment of Burkitt's and non-Burkitt's undifferentiated lymphoma

Because of the aggressive nature and frequent recurrence of malignant lymphomas of the undifferentiated type, we used a multi-drug induction chemotherapy regimen that has met with some success in children with similar type of histopathology followed by intensification and 8 cycles of consolidation chemotherapy in an attempt to prolong the duration of remission and survival in adult patients with this diagnosis. Fifty-one patients (median age 35 years) with undifferentiated malignant lymphoma were collected over a 4 year period (1984-1988) and entered into a phase III protocol done under the auspices of the Eastern Cooperative Oncology Group (ECOG). Six patients who had their diagnosis made at surgery and had resection of their tumor were excluded from analysis of response to therapy. Sixty percent of the patients had Stage IV disease. Sixteen patients had marrow involvement and five had central nervous system (CNS) disease. None of the patients received CNS radiation therapy. The 45 patients evaluated for response showed a response rate of 67% (30/45) and a complete response rate of 40% (18/45). Thirteen responders continue disease-free with a median follow-up of > 40 months and have an estimated 5 year survival of 80%. Only two treatment related deaths were reported for the entire group. Patients with undifferentiated non-Burkitt's lymphoma had a longer survival than those with undifferentiated Burkitt's. We concluded that adult patients with undifferentiated lymphomas could be treated successfully with an aggressive multi-drug chemotherapy regimen, consisting of multiple alternating cycles of non-crossed-resistant chemotherapy. Toxicity with this aggressive prolonged regimen was acceptable.

Epstein-Barr virus as an agent of haematological disease

Epstein-Barr virus (EBV) encodes genes that permit its persistence in human B lymphocytes and genes that ensure its replication in epithelial cells. Immune restraints on the virus are usually so effective that most EBV infections are limited to a minute fraction of B lymphocytes and of epithelial cells. As a result, most EBV infections are never symptomatic. Occasionally, the virus causes disease, often with the cooperation of the immune system or other less characterized cofactors. Infectious mononucleosis, a generally self-limited lymphoproliferative illness common in adolescents and young adults, is due to primary EBV infection and to the brisk cellular immune response it elicits. Lymphoproliferative disorders of EBV-infected B cells arise almost exclusively when cellular immunity is grossly compromised. EBV-positive Burkitt's lymphoma contain a translocated and deregulated c-myc oncogene and EBV-positive non-Hodgkin's lymphomas are characterized by the presence of Reed-Sternberg's and Hodgkin's cells, features that have not been directly linked to EBV. Many recent observations, however, including evidence that virus infection precedes malignant transformation and is often associated with a characteristic pattern of viral gene expression, provide continued interest in the relationship between the virus and these haematological malignancies.

Therapy of B-cell acute lymphoblastic leukaemia in childhood: the BFM experience

In 1981 the BFM group introduced a new treatment strategy for B-ALL based on two alternating 5-day courses of chemotherapy delivered in short intervals up to a total of eight. The therapy courses were composed of fractionated cyclophosphamide, MTX 0.5 g/m2 (24-h infusion), i.t. MTX therapy, and ara-C/VM26 alternating with doxorubicin. The development of the therapy strategies during the subsequent two studies was characterized by shortening treatment duration from eight to six courses, and intensification of CNS chemotherapy in study ALL-BFM-83, and the introduction of HD-MTX (5 g/m2, 24-h infusion) in study ALL-BFM-86. In study ALL-BFM-81, CNS therapy consisted of ID-MTX in combination with i.t. MTX and RX. CNS-positive patients received complete neuroaxis irradiation. In study ALL-BFM-83, CNS chemotherapy was intensified by adding dexamethasone, while MTX/ara-C were administered intraventricularly. Spinal irradiation for CNS-positive patients was omitted. In study ALL-BFM-86, i.t. MTX/ara-C/prednisolone therapy was introduced in combination with HD-MTX but the intraventricular route of drug administration was no longer used. Radiotherapy was omitted completely. In all, 87 patients were enrolled, 22 (eight CNS positive) in study ALL-BFM-81, 24 (seven CNS positive) in study ALL-BFM-83, and 41 (none CNS positive) in study ALL-BFM-86. The estimated 5-year duration of EFS was 40% in study ALL-BFM-81, 50% in study ALL-BFM-83, and 78% in study ALL-BFM-86 (minimal follow-up 36 months). Nineteen of 24 relapses occurred while on therapy or shortly thereafter. In study ALL-BFM-81, the CNS was the most frequent site of failure. In ALL-BFM-83 there were no isolated CNS relapses but more BM relapses occurred. In ALL-BFM-86 localized manifestations were the predominant site of failure, no isolated BM relapses occurred, and only one CNS relapse was diagnosed. No single parameter exerted a consistent influence on outcome with one exception. The presence of residual disease after the first two courses was correlated with an increased risk of therapy failure. Our conclusions from the three studies are listed below. An intensive, short-pulse therapy delivered within a 4 month period is highly effective in the treatment of B-ALL. Prolonged therapy duration is of no value. In addition to fractionated cyclophosphamide-ifosfamide, a 24-h infusion of HD-MTX5 g/m2 in conjunction with an i.t. therapy is a very important component for prevention of both systemic and CNS relapses.(ABSTRACT TRUNCATED AT 400 WORDS)

Primary central nervous system Burkitt's lymphoma presenting as Guillain-Barré syndrome

A rare case of CNS Burkitt's lymphoma presenting as acute Guillain-Barré syndrome is presented. A 6-year-old previously healthy female presented with acute onset of limb and truncal weakness, involvement of ocular and bulbar nerves, and areflexia. The clinical diagnosis of Guillain-Barré syndrome prompted treatment with intravenous gammaglobulin with no response. A lumbar puncture following revealed marked pleocytosis, elevated protein, and decreased glucose. Immunological, cytological, and molecular studies of these cells confirmed the diagnosis of Burkitt's lymphoma IgM, kappa with t(8;14) and rearrangement of the J and kappa immunoglobulin chains. Aggressive systemic and intrathecal chemotherapy were started and within 5 days remission was achieved. The child is in complete remission 2 years from diagnosis. Although very rare, CNS lymphoma should be taken into account in every patient presenting with the clinical features of acute polyneuropathy.

Lymphomas in University College Hospital, Ibadan, Nigeria

The authors reviewed 508 cases of lymphoma seen during a 16-year period in University College Hospital, Ibadan, Nigeria. Hodgkin's disease was diagnosed in 95 (18.6%) patients, of which 45% had mixed cellularity type; 19%, lymphocyte predominance; 18%, nodular sclerosis; and 18%, lymphocyte depletion. The age distribution showed a single mode in the 11 to 25-year-old group. Male preponderance was more marked in children who made up 32% of the Hodgkin's disease patients. Non-Hodgkin's lymphoma occurred in 413 cases, of which 296 (71.7%) were high-grade malignancies. Burkitt's tumor occurred in 211 (41.5%) patients, 95% of whom were children, and showed a male to female ratio of 1.7:1. Compared with previous findings in this hospital, Hodgkin's disease showed increased proportions of the lymphocyte predominant and nodular sclerosing types. However, the characteristics of Burkitt's lymphoma did not change appreciably in the last three decades.

Burkitt's lymphoma of the tonsil

A case of Burkitt's lymphoma involving the tonsil in a 10-year-old Bedouin boy, is presented. The biological behaviour and the clinical presentation of this unusual neoplasm are discussed and the English language literature is reviewed. The diagnosis was made by histological examination, electron microscopy and confirmed by immunohistochemistry. The patient showed an excellent symptomatic response to surgery and chemotherapy.

B-cell acute lymphocytic leukemia in HIV-antibody-positive patients

B-cell non-Hodgkin lymphoma (NHL) has been well described in association with human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome (AIDS). Many of these lymphomas are of the diffuse, aggressive, subtype B-cell NHL, including Burkitt and Burkitt-like lymphoma. Recently, there have been reports of B-cell acute lymphocytic leukemia (ALL), Burkitt type, in patients who were either HIV antibody-positive or at high risk for AIDS. We have seen three cases of B-cell ALL, Burkitt type, and herein describe their clinical and laboratory characteristics. All patients were HIV antibody-positive. Since stage IV Burkitt lymphoma in blood phase and B-cell ALL, Burkitt type, represent a continuum of the same disease, and since it is also an aggressive B-cell malignancy, we suggest that B-cell ALL, Burkitt type, in HIV antibody-positive patients should support the diagnosis of AIDS.

Correlations between acute lymphoid leukemia (ALL) immunophenotype and clinical and laboratory data at presentation. A study of 350 patients

The phenotypes of malignant cells from 350 untreated patients with acute lymphoblastic leukemia (ALL) were determined at diagnosis with the use of a panel of monoclonal antibodies to leukocyte antigens. According to the phenotypes seen, the cases were divided into five groups, pre-B ALL, B-ALL, T-ALL, MO-ALL, and undifferentiated ALL. Each group was subdivided, resulting in 11 defined immunologic subtypes. Correlations between clinical and laboratory features were investigated at presentation. ALL of early-B phenotype associated with elevated cell counts occurred more often in female and infant patients than in male patients. Involvement of the central nervous system was frequent in B-ALL, which occurred mostly in male patients. A male prevalence was also seen in ALL of T-lineage in which significant differences regarding clinical characteristics and leukocyte counts appeared among the four subtypes. The clinical relevance of phenotypic subcategorization is supported by our observations.

African Burkitt's lymphoma in the Cape province of South Africa and in Namibia

The clinical features, incidence and pattern of jaw involvement, and seasonal occurrence in relation to 22 patients with Burkitt's lymphoma in the Cape province and Southwest Africa were analyzed. The mean age, male dominance, and pattern of organ involvement paralleled typical African Burkitt's lymphoma. Development of the patients' disease was more likely during the rainy season. The frequency and pattern of jaw involvement resembled typical African Burkitt's lymphoma. The frequency of jaw involvement was similar in white and nonwhite patients. Members of all racial groups had typical African Burkitt's lymphoma.

Hybrid acute leukemia in an HIV-antibody-positive patient

Although the great majority of acute leukemias have been designated as being of lymphocytic or myelocytic origin, recent reports have described elements of both in some patients. We describe here the first case of hybrid acute leukemia in an HIV-antibody-positive patient as well as the first hybrid involving B-cell (Burkitt) acute lymphocytic leukemia and acute myelomonocytic leukemia proven by cytochemical, immunologic, and cytogenetic methods. This case illustrates the increasingly complex difficulties in the diagnosis and treatment of AIDS-related malignancies.

The cytogenetics of childhood leukemia: clinical and biologic implications

Cytogenetic studies have revealed a broad spectrum of abnormalities in the chromosomal make-up of human leukemic cells. These abnormalities are acquired during the process of malignant transformation within the neoplastic clone and reflect the genetic lesions and ablations that have occurred. Because cytogenetic abnormalities are tightly linked to the molecular events that lead to leukemogenesis, it is not surprising that these features correlate with immunophenotypic and morphologic features of the leukemic cells, as well as with the clinical characteristics of children at diagnosis and their responsiveness to therapy. Molecular analysis of the disordered structure or disrupted regulation of genes located at critical chromosomal breakpoints in leukemic cells should continue to provide important insight into normal and aberrant hematopoietic cell function.

B-cell acute lymphoblastic leukaemia: clinical and biological aspects

Acute lymphoblastic leukaemia of B-cell phenotype (B-ALL) is uncommon. We studied eight cases of B-ALL, investigating the clinical characteristics as well as the biological features. Cytology revealed a typical L3 profile in most cases, but in one case the morphological diagnosis was L2 and morphometric analysis indicated that the blasts in B-ALL were larger than in other ALLs. Cytogenetic study detected the typical translocations (8; 14) and (8; 22) in most of the cases. Abnormalities of the long arm of the chromosome 1 were found in four cases and a major aneuploidy was observed in one case. Cell-cycle analysis showed a high degree of proliferation with, in all cases, a small fraction of cells in G1 with low protein content (corresponding to early G1). All these biological characteristics must be related to the poor prognosis of this disease.

Cytogenetic evaluation of bone marrow involvement in Burkitt's lymphoma

Twenty-six bone marrow samples from 21 patients with Burkitt's lymphoma were examined cytogenetically after short-term culture. Clonal chromosomal changes were detected in one of 18 samples from morphologically normal marrows, and in three out of six samples with verified tumor invasion. Three patients had the translocation (8;14)(q24;q32) and one had t(2;8)(p12;q24). Two samples with suspect tumor involvement (less than 5% putative tumor cells) showed no clonal abnormalities. In two samples without morphologic bone marrow infiltration and with only normal metaphases in short-term cultures, clones with t(8;14)(q24;q32) were revealed after a longer time (3-12 weeks) spent in vitro.

High risk lymphoblastic leukemia in children: prognostic factors and management

Most of the presenting clinical and biological features that have prognostic significance in childhood acute lymphoblastic leukemia are closely related, although they are not equally important. The predictive value of these factors can vary with the efficacy of the therapy delivered. Although there are no uniform criteria to define a high-risk group, an initially high leukocyte count and an age less than 1 or greater than 10 years at diagnosis are universally accepted as the most powerful indicators of a poor outcome. With advances in immunology and genetics, blast cell immunophenotypes and karyotypic abnormalities have emerged as independently significant prognostic factors. With this information, therapy can be tailored for patients at various risks of treatment failure. Using early aggressive therapy, more than 60% of patients are expected to be long-term survivors, but better therapy is still needed for those at high risk of relapse. Innovative approaches, such as bone marrow transplantation, phenotype-specific treatment, or pharmacokinetic-directed therapy, are being tested.

Multiparameter characterization of L3 leukemia cell populations

Multiparameter analysis of 14 consecutive patients with L3 cell populations (FAB classification) in bone marrow showed consistently high mean cellular RNA content but heterogeneity with respect to percent cels in S- and G2M-phases of the cell cycle, cell surface phenotype, cytogenetic abnormalities, cellular DNA content, and nuclear activities of terminal deoxynucleotidyl transferase. Five of the 14 patients had the characteristic profile of L3 leukemia with high RNA content, a typical t(8;14) or t(8;22) translocation, low Tdt, B-cell surface phenotype, pseudodiploid modal number of chromosomes, high proliferation and normal DNA index. The remaining 9 patients had features thought to be unusual and they were very heterogeneous. Median survival time from time of diagnosis was 115 days with no patient alive after 474 days. The survival times exhibited excellent correlation with a parametric model assuming exponential distribution. Accordingly, the presence of abnormal DI predicted for decreased, and the presence of t(8;14) or pseudodiploidy was associated with increased survival rates. However, due to the small number of patients in this study, generally applicable conclusions should be drawn only from a collection of larger numbers of cases of this rare type of leukemia.

Identification of L3 leukemia and Burkitt's lymphoma cells by flow cytometric quantitation of nuclear and cellular RNA and DNA content

Separate quantitations of nucleic acids of isolated nuclei and cells of L3 leukemia/Burkitt's lymphoma cell populations of peripheral blood (PB), bone marrow (BM) and lymph node (LN) cell suspensions of 17 patients were performed by acridine orange (AO) flow cytometry (FCM). The cell populations were analysed with respect to cell cycle characteristics and DNA/RNA distribution histograms of cells in various compartments of the cell cycle using mean value, coefficient of variation (CV), third moment about the mean as a measure of skewness (MOM3). The correlations between numbers of L3 blasts detected by microscopy and aneuploid cells quantified by FCM in 10 patients with aneuploid disease were r = 0.75 and r = 0.85 for BM and PB cell populations, respectively. Content of both nuclear and cellular RNA was 3-4 times higher in L3 cells than in normal donor lymphocytes. Percentages of cells in SG2M phase of L3 populations were significantly different from control populations in BM (p less than 0.01) and PB (p less than 0.0001). All samples with L3 blasts had abnormal CV of the DNA, and abnormal CV and MOM3 of the RNA peaks of G0/1 cell histograms. All samples with no blasts by morphology had normal DNA and RNA patterns. AO FCM correctly classified all specimens as involved or not involved with disease in accordance with the cytomorphological diagnoses. Combining AO FCM with prior cell separation increased the sensitivity of the method to detect abnormal cells to 0.02%, or 0.5 L3 cells per microliter of blood.

Cell surface markers in leukemia: biological and clinical correlations

Recent advances in analysis of leukemic cell phenotypes using cell surface markers have provided important insights into leukocyte differentiation and the cellular origin of leukemia. In addition to the traditional cell surface markers, i.e., surface membrane immunoglobulin and receptors for sheep erythrocytes that define B and T lymphocytes, highly specific monoclonal antibodies have been developed that discriminate various stages of human lymphocyte and granulocyte differentiation. Explorations of the detailed phenotypes of leukemic cells in relation to normal hemopoietic differentiation reveal that consistent, composite phenotypes of different subclasses of lymphoid malignancies closely mimic those of corresponding normal cells at equivalent levels of maturation. This is exemplified in lymphoma cells (chronic lymphocytic leukemia of B or T type, Sezary Syndrome, immunocytoma) that resemble mature and immunocompetent T and B cells, in T cell acute lymphoblastic leukemia (T-ALL) (equivalent to thymus cells) and in non-T ALL (corresponding to lymphoid progenitor cells in the bone marrow). The major phenotypes documented in different leukemias represent the level of maturation arrest imposed on the dominant subclone; this is determined by, but not necessarily synonymous with, the target cell and associated clonogenic cell population in the leukemia. The clinical significance of immunodiagnosis of leukemia cell types becomes best evidenced in acute leukemias. Besides the improvement of diagnosis by using objective criteria, clinically useful subclassifications became evident: five major subtypes of ALL are now recognized, including unclassified or null ALL, common ALL, pre-B-ALL, B-ALL and pre-T/T-ALL. In addition to disclosing that ALL is an heterogeneous disease, such classifications have proved to be prognostically significant. This is exemplified in 248 children and 145 adults with ALL which were analysed for cell type and clinical data. In addition to their utility in leukemia classification, monoclonal antibodies that identify leukemia associated antigens are becoming used therapeutically, e.g., to lyse residual leukemia cells from remission bone marrows removed from leukemia patients before reinfusion. New approaches to the treatment of leukemia in which the objective is to encourage maturation of leukemia cells rather than to achieve leukemia eradication, can be monitored by phenotyping the alterations of the cell surface, and cell markers may hopefully be useful in identifying cell types that can be induced to differentiate.

Morphological heterogeneity in childhood B cell acute lymphoblastic leukaemia

Considerable heterogeneity of lymphoblast morphology in childhood B cell acute lymphoblastic leukaemia has been observed. One case showed unusual monocytic features and emphasised the need for marker studies in the accurate definition of acute lymphoblastic leukaemia phenotypes. B cell acute lymphoblastic leukaemia is rare but may have been previously underestimated by morphological misinterpretation. Further information is required to determine if the different morphological features of this condition are of clinical and prognostic importance.

Pediatric oncology group utilization of immunologic markers in the designation of acute lymphocytic leukemia subgroups: influence on treatment response

The clinical application of blast cell immunophenotype testing is important in childhood ALL for the following reasons. (1) Knowledge of the immunologic group is important in predicting prognosis. Prognostic grouping may prove to be accomplished best by using a combination of traditional risk factors and immunologic phenotyping. However, definition of traditional risk factors may vary within the immunologic groups of ALL. (2) In assessing the relative effectiveness of different treatment regimens for children with ALL it is important to make comparisons among patients within the same major immunologic groups of ALL. (3) Identification of specific immunologic groups of patients within ALL may help in designing therapy for each group. The POG has already made preliminary attempts in this direction for T-ALL and B-ALL. However, leukemia species-specific therapy is still only a long-range goal. Laboratory research must endeavor to identify additional biologic characteristics peculiar to each major immunologic group of ALL. These characteristics may dictate therapeutic maneuvers in the future.

Jaw involvement in American Burkitt's Lymphoma

A total of 100 patients with American Burkitt's lymphoma (AMBL) (mean age, 15 years; M:F ratio 3:1; 3% black) have been treated at the National Cancer Institute since 1964. Eighteen of these had jaw involvement, 16 at presentation and 2 at relapse (mean age, 16 years; M:F ratio 1.6:1). None of these 18 patients was black. Of the 16 patients presenting initially with jaw tumors, 14 were first evaluated by their dentist; 8 were 16 years of age or older (adults) and 6 were younger than 16 years of age (children). Toothache and perioral numbness were the most frequent findings in adults, whereas toothache, loose teeth, intra-oral and extra-oral swelling were the most common complaints in children. Ten patients were treated with antibiotic therapy and/or dental extractions for presumed tooth infection. The distribution of jaw lesions was: unilateral mandibular (7), unilateral maxillary (4), bilateral mandibular (5), and four quadrants (2). Radiologic evaluation was abnormal in all 17 cases evaluated. Only three patients (all children) had disease limited to the jaw. Four of eight children and 3 of 10 adults are long-term survivors with a median follow-up of seven years (range, 2-15 years). American Burkitt's lymphoma with jaw involvement differs from African Burkitt's lymphoma (AFBL) with jaw involvement in a number of ways: (1) the incidence of jaw tumors in adults is similar to that in children; (2) the incidence of jaw tumors is not greater in males; (3) tumor is considerably more limited in extent with a single quadrant mandibular lesion being the most common presentation; and (4) clinical presentation also differs, with toothache and perioral numbness, uncommon in AFBL, being the most frequent complaints. These marked differences in the frequency and clinical characteristics of jaw tumor of AMBL and AFBL are consistent with other findings indicating that these diseases may differ phenotypically.

"Target" cells, cellular phenotypes, and lineage fidelity in human leukaemia

A detailed analysis of lymphoid leukaemia cells with a panel of monoclonal antibodies plus other markers indicates a striking conservation of phenotype that closely mimics that of normal lymphoid precursor or progenitor cells and reflects the imposition of maturation arrest. The composite phenotypes detected show some minimal deviations or asynchronies (with respect to maturation "stages") but are faithful with respect to cell lineage. These observations are suggested to shed light on the available "target" populations for lymphoid malignancy in humans and challenge the view that dedifferentiation or qualitatively aberrant gene expression is common and important in malignancy. They are further taken to support the view that normal gene products that regulate or couple proliferation and maturation are critically involved in the successive clonal selection events underlying the evolution of leukaemia. No qualitatively unique and consistent leukaemia "markers" may exist or be required. The only exception to this rule are the nonrandom chromosome changes, which, it is suggested, involve genetic loci critical to the regulation of growth and maturation in particular normal cell types.

Patient with acute B-cell leukemia of Burkitt's type (L3) and marker chromosomes including an (8;14) translocation

A 20-year-old man with acute B-cell leukemia of Burkitt's type (L3) presenting unusual début symptoms with jaw involvement is reported. The leukemic cells revealed chromosomal abnormalities including four marker chromosomes [1q+, 6q-, t(8;14)].