Arnold Criel

Further characterization of morphologically defined typical and atypical CLL: a clinical, immunophenotypic, cytogenetic and prognostic study on 390 cases

We analysed a group of 390 patients, diagnosed with chronic lymphocytic leukaemia (CLL). Cases were subclassified as morphologically typical and atypical CLL according to the criteria of the FAB proposal. Typical CLL cases were mostly diagnosed at a low‐risk stage (Binet A/Rai 0), required no immediate treatment and expected a long survival; atypical CLL cases mostly presented at a more advanced risk stage (Binet B/Rai I–II), usually required immediate treatment and their survival was shorter. Moreover, clinical staging was of prognostic significance in typical but not in atypical cases.  In typical CLL, del(11q) was the most common chromosomal abnormality (21%) whereas in atypical CLL trisomy 12 was found in about 65% of the cases documented with an abnormal karyotype. Although chromosomal abnormalities were associated with a poor survival in typical CLL, they are of no prognostic significance in atypical CLL.  Based on these data, we conclude that subtyping CLL by morphology enables the identification of two groups of cases, each characterized by a specific clinical presentation, different cytogenetic abnormalities and prognostic parameters. We speculate that these two groups may represent two related, but different, diseases with different prognostic parameters and a different survival.

Genetic abnormalities in chronic lymphocytic leukemia and their clinical and prognostic implications

Clonal chromosome abnormalities can be detected in approximately 50% of patients with chronic lymphocytic leukemia (CLL). The most common changes are trisomy 12, followed by structural abnormalities of 13q, 11q, 6q, and 14q. By fluorescence in situ hybridization (FISH), these aberrations can be demonstrated even in cases with insufficient mitotic yield or a normal karyotype. The biologic consequences of trisomy 12 are unknown, but a gene dosage effect is suspected and studies on partial trisomy 12 indicate that the region 12q13 to 12q22 might be of particular pathogenetic importance. Trisomy 12 is strongly associated with atypical lymphocyte morphology and seems to be a secondary event in leukemogenesis, as shown by combined immunophenotyping and interphase FISH. Structural abnormalities of 13q frequently involve hetero- and homozygous deletions of a region in 13q14, distal to the retinoblastoma gene, which may be the site of a tumor suppressor gene. In contrast to a normal karyotype or structural changes of 13q, complex karyotypic abnormalities, high percentage of abnormal metaphases, trisomy 12 and structural changes involving the P53 tumor suppressor gene on 17p13 are adverse prognostic indicators. Cytogenetic and molecular findings provide important diagnostic, clinical, and prognostic information which can contribute to treatment decisions and follow-up of CLL patients.

Platelet activation and vascular damage in gestational hypertension

Increased plasma fibronectin levels are a highly sensitive and specific predictor of gestational hypertension. Of a total of 105 apparently healthy normotensive primigravid women seen at the outpatient clinic, 10 with increased plasma levels of fibronectin (mean +/- 2 SD), were compared with 14 controls. Parameters of early vascular damage (laminin, preprocollagen III), platelet activation (beta-thromboglobulin, platelet factor 4), and coagulation (thrombin-antithrombin III complexes, fibrinopeptide A) were measured at regular (weekly or monthly) intervals. Abnormal values of laminin (p less than 0.005) and fibronectin (p less than 0.0001) were found up to 4 weeks before the onset of clinical disease. Levels of beta-thromboglobulin (p less than 0.0001) were also elevated at least 4 weeks before the appearance of clinical symptoms. Our results show that increased levels of laminin, fibronectin, and platelet activation, as indicated by beta-thromboglobulin levels, are preclinical features of gestational hypertension and indicate that vascular damage has occurred. Fibrin formation would appear to occur later.

Deletions of the long arm of chromosome 7 in myeloid disorders: loss of band 7q32 implies worst prognosis

Clinical and cytogenetic data were analysed in 54 patients with acute non‐lymphocytic leukaemias (ANLL) or MDS (myelodysplastic syndromes) and deletion of the long arm of chromosome 7 (7q−), in order to determine if there is a commonly deleted region in 7q and to establish possible correlations between karyotypic features, such as karyotype pattern, karyotype complexity, associated anomalies, and/or the type of deleted segments, and outcome of patients with these disorders.

The concept of typical and atypical chronic lymphocytic leukaemia.

Subdivision of CLL into typical and atypical subtypes, as proposed by the FAB group in 1989, is not yet widely accepted and its clinical significance is still debated. In recent years, however, a strong correlation was found between atypical morphology trisomy 12 and an aberrant immunophenotype. In the first part of this review we discuss current concepts and generally accepted data on morphology, immunophenotype, genetic abnormalities, clinical features and prognostic factors in CLL. Subsequently, based on our own series and other recently published data, we analyse the validity and clinical impact of classifying CLL into typical and atypical entities and demonstrate that they may represent two closely related but different entities.

FISH identifies different types of duplications with 12q13-15 as the commonly involved segment in B-cell lymphoproliferative malignancies characterized by partial trisomy 12

Clinical, cytogenetic, fluorescence in situ hybridization (FISH), and Southern blot data of 18 patients with different subtypes of B‐cell non‐Hodgkins lymphoma, cytogenetically characterized by partial trisomy 12, are presented. These chromosomal changes occurred predominantly in clinically progressive chronic lymphocytic leukemia, mixed cell type, and advanced‐stage follicle center cell lymphoma at the time of relapse or transformation into diffuse large cell lymphoma. Partial trisomy 12 consistently included the long arm of chromosome 12, either completely or partially, and resulted from dup(12q) or other rearrangements involving chromosome 12. The duplications were cytogenetically identified as dup(12)(q13q23), dup(12)(q13q22), or dup(12)(q13q15) in follicle center cell lymphoma or t(14;18)‐positive diffuse large cell lymphoma; dup(12)(q13q22) or dup(12)(q13q24) in chronic lymphocytic leukemia; and dup(12)(q13q21) in a case of t(14;18)‐negative diffuse large cell lymphoma. FISH, using library probes and a panel of YAC probes, mapped along the long arm of chromosome 12, confirmed the cytogenetic results in all cases analyzed except for three cases of t(14;18)‐positive follicle center lymphoma or diffuse large cell lymphoma with dup(12q). In these cases, FISH showed similar, possibly identical, duplications, which involved a region more centromeric (12q11‐21) than assumed by karyotypic analysis (12q13‐22 or 12q13‐23) and included alphoid DNA sequences, a combination hitherto unknown. In addition, commonly duplicated regions of chromosome 12 could be defined: 12q11‐21, including alphoid DNA sequences for follicle center cell lymphoma or t(14;18)‐positive diffuse large cell lymphoma, 12q13‐22 for chronic lymphocytic leukemia, and 12p13‐q15 for marginal zone cell lymphoma, all of which overlapped in 12q13‐15. Whether these regions, especially 12q13‐15, may contain genes which are important in malignant transformation or disease progression of B‐cell lymphoproliferative malignancies characterized by complete or partial trisomy 12 remains to be determined. Genes Chromosomes Cancer 20:155–166, 1997.

Prognostic Significance of Bone Marrow Trephine and Peripheral Blood Smears in 55 Patients with Mantle Cell Lymphoma

Bone marrow trephine and peripheral blood smears taken at diagnosis of 55 cases of well-documented mantle cell lymphomas were reviewed in order to analyse the leukaemic involvement in this non-Hodgkins lymphoma: its incidence, morphological characteristics and prognostic significance. A median survival of 36 months was found. The median age was 61 and the male to female ratio was 4:1. Morphologically 7 cases presented with a mantle zone pattern, all the others had a diffuse pattern. Involvement of the bone marrow was found in 58% and a trend for prolonged survival in patients with a negative trephine was seen. An absolute lymphocytosis above 10,000 mu l was found at diagnosis in 5 cases (10%) and had a statistically significant impact on survival. An additional 5 cases developed frank leukaemia during the course of the disease and died within 1 to 6 months of this evolution, suggesting that marked lymphocytosis is more a terminal event associated with an extremely poor prognosis than a presenting symptom. Finally we identified an additional parameter with statistically prognostic significance, namely, the presence of atypical cells in the peripheral blood even in the absence of an increased lymphocytosis.

BCL3 rearrangement and t(14;19)(q32;q13) in lymphoproliferative disorders

Translocation t(14;19)(q32;q13) is a rare but recurrent abnormality in chronic lymphocytic leukemia and small cell lymphoma. It has been associated with rearrangements of the BCL3 gene, which is located at the breakpoint on chromosome 19 and is juxtaposed to the immunoglobulin heavy chain locus on chromosome 14 as a result of the translocation. This results in transcriptional up‐regulation of the BCL3 gene, which encodes a transcription coactivator, an 1‐κB protein, probably contributing to disease progression. We found, among 4,487 cytogenetic analyses of lymphoproliferative disorders, six cases with a t(14;19)(q32;q13), five of which showed the classical t(14;19)(q32;q13) and one of which showed a three‐way translocation t(7;19;14)(q21;q13;q32). The 14;19 translocation never occurred as a single abnormality; additional aberrations included trisomy 12 and several structural abnormalities. The cytogenetic examination was supplemented by molecular analysis using available probes for the BCL3 locus (pα1.4P and pα5B) in 1,150 of the 4,487 patients. Rearrangements of BCL3 involvement could only be confirmed using long‐range restriction mapping, indicating that, with the usually available BCL3 probes, rearrangements of this locus may be missed. Genes Chromosom Cancer 14:00–00 (1995).

Trisomy 6 is the hallmark of a dysplastic clone in bone marrow aplasia.

Clonal hematopoiesis with trisomy 6 as the sole karyotypic change was revealed by cytogenetics in two cases of aplastic anemia. In both patients, dyserythropoiesis was characterized by asynchrony of maturation between nucleus and cytoplasm, binucleated elements, and intercytoplasmic connections. In addition to conventional cytogenetics, the size of the trisomic clone was evaluated by fluorescence in situ hybridization on fixed cells at diagnosis and in the course of the disease by using an alpha-satellite centromeric probe for chromosome 6. Moreover, in situ hybridization on bone marrow smears showed that dysplastic erythrocytes as well as myeloid cells belonged to the trisomic clone. Trisomy 6 identifies a subgroup of hematologic disorders with bone marrow hypo-aplasia and dyserythropoiesis.

del(7q) in chronic B-cell lymphoid malignancies

Twelve patients with diagnosis of B-cell non-Hodgkins lymphoma/leukemia and del[7q] were studied for their clinical, cytogenetic, and molecular characteristics. Eleven patients were classified as small cell lymphoma whereas one had a diffuse large cell lymphoma. Lymphoplasmacytic features were observed in six out of eleven small cell lymphomas. Morphologically and immunologically these small cell lymphomas could be classified as chronic lymphocytic leukemia (typical or atypical; 4 cases), marginal zone lymphoma (splenic lymphoma with villous lymphocytes; 1 case), mantle cell lymphoma (2 cases), or nonspecified, non-Hodgkins lymphoma (4 cases). Eleven of twelve patients presented with peripheral blood and bone marrow involvement. Two of twelve cases showed del[7q] as the sole anomaly. Two different types of deletions were present: ten cases had del(7)(q21q31) and two cases had del(7)(q31q34). Cases that could be molecularly investigated did not show any involvement of BCL2, BCL3, or BCL6, and only one case had BCL1 rearrangement. The data indicate that del(7q) is associated with a subset of mature small B-cell lymphoproliferative disorders of which some but not all show lymphoplasmatic features.