Comparative biochemical and cytogenetic studies of childhood acute lymphoblastic leukemia with the Philadelphia chromosome and other 22q 11 variants

We studied the relationship of direct karyotypes, determined at diagnosis and remission, to Abelson-related tyrosine kinase activity and the cytogenetic features of erythroid and myeloid colonies derived from remission marrow of six children with acute lymphoblastic leukemia (ALL). These patients had either the characteristic Philadelphia chromosome (Ph1) [t(9;22)(q34;q11)] or cytogenetically similar variants with a 22q11 breakpoint but no detectable cytogenetic involvement of 9q34. The findings suggested two distinct subtypes of ALL: one defined by t(9;22)(q34;q11) and expression of P185BCR-ABL tyrosine kinase and one with variant karyotypes and no P185BCR-ABL expression. The former comprises cases with Ph1 + marrow cells and Ph1 + erythroid and (or) myeloid colonies in remission marrow and others in which the t(9;22) is undetectable in remission marrow cells. In the latter subgroup, the disease may reflect more extreme mosaicism with a similar stem cell that is cytogenetically undetectable. Variant karyotypes included a del(22)(q11) in one patient and a t(6;22;15;9) (q21;q11;q?22;q21) in another; in both instances, the malignant blast cells lacked P185BCR- ABL expression. Thus ALL with t(9;22)(q34;q11) should be distinguished from ALL with other involvement of the 22q11 breakpoint by molecular studies including protein expression. The diversity of karyotypic findings in cases with involvement of 22q11 suggests at least two mechanisms of leukemogenesis in patients with ALL defined by this breakpoint.     

Abnormalities of 3q21 and 3q26 in myeloid malignancy: a United Kingdom Cancer Cytogenetic Group study

Summary. Cytogenetic and clinical details are presented for 66 patients with myeloid malignancy and chromosome abnormalities of 3q21 and/or 3q26 (3qabns). Bone marrow and/or peripheral blood morphology was assessed for 52 cases. 3qabns in Philadelphia negative (Ph–ve) and positive (Ph + ve) cases were inv(3)(q21q26), (21 Ph-ve, 6Ph + ve); t(3;3)(q21;q26) (nine Ph-ve, four Ph + ve); and t(3;21)(q26;q22) (four Ph-ve, six Ph + ve). Ph-ve cases also had t(l;3)(p36;q21) (three cases), and t(3;5)(q21;q31)/ (q21;q35)/(q26;q21) (five cases aged <40 years). Three cases, aged < 30 years, had t(3;12)(q26;p13) which defines a new 3qabn subgroup. Monosomy 7 and/or 5q- accompanied inv(3) or t(3;3) in 17/30 cases. All cases had a myeloid malignancy (predominantly AML M1, M4 or M7), frequent trilineage myelodysplasia, and markedly abnormal megakaryopoiesis with micromegakaryocytes (<30/mi). Thrombocytosis occurred in two cases only. Most Ph + ve cases were in myeloid blast crisis and in Ph + ve cases alone, micro-megakaryocytes were uniquely small (10 μm) in 7/11 cases. There were equal numbers of males and females. Seven secondary leukaemias were found in Ph–ve cases with inv(3), t(3;3), t(3;21), t(l;3) or del(3)(q21). Three cases with t(3;21) (one Ph + ve) were de novo AML or had de novo aplastic anaemia. Survival was rarely greater than 12 months from detection of the 3qabn.     

Lymphocyte malignancy and chromosome 14: structural aberrations involving band q11

Five patients with lymphocytic malignancies were found to have structural aberrations of chromosome 14, all involving band q11. The malignant cells of all five cases were analyzed by immunofluorescence to establish immunologic phenotypes. Three patients had T lymphoblastic lymphoma/leukemia with mediastinal masses (cases 1, 2, and 3); one patient had peripheral T cell lymphoma (case 4); and one patient had acute lymphocytic leukemia, common acute lymphoblastic leukemia antigen positive (case 5). Although aberrations of chromosome 14 frequently are associated with lymphocytic malignancies, these abnormalities most often result in extra material on the long arm, 14q+. However, none of the five patients reported here had a 14q+. Cases 1 and 2 had t(9;14)(q34;q11) and t(11;14)(p11 or 13;q11), respectively. Case 3 showed del(14)(q11), and cases 4 and 5 showed inv(14)(q11q32). Structural aberrations resulting in 14q- and inv(14) appear to occur infrequently. The five cases in this report, in conjunction with those found in the literature, indicate a strong association between breaks at 14q11 and T lymphocytic malignancies.     

Progression from myelodysplastic syndrome to acute lymphoblastic leukaemia with Philadelphia chromosome and p190 BCR-ABL transcript

We describe a patient with Philadelphia chromosome (Ph¹)-positive acute lymphoblastic leukaemia (ALL) who developed it 2.5 years after being diagnosed with myelodysplastic syndrome (MDS). The patient initially had refractory anaemia (RA), but progressed to refractory anaemia with excess blasts (RAEB) 2 years later, that terminated in ALL. An immunophenotypic analysis of the lymphoblasts revealed CD10 and CD19 positive cells. The karyotype was normal 46,XY in RA phase, 46,XY,20q– during the RAEB phase, and 46,XY, t(9;22)(q34;q11), 20q– during the ALL phase. Furthermore, p190 BCR-ABL mRNA was detected in the ALL blasts. These findings indicate that this ALL arose from the MDS clone through multiple cytogenetic evolutions, the final event of which was the acquisition of p190 BCR-ABL type Ph¹     

Translocations targeting CCND2, CCND3, and MYCN do occur in t(11;14)-negative mantle cell lymphomas

The genetics of t(11;14)(q13;q32)/cyclin D1–negative mantle cell lymphoma (MCL) is poorly understood. We report here 8 MCL cases lacking t(11;14) or variant CCND1 rearrangement that showed expression of cyclin D1 (2 cases), D2 (2 cases), and D3 (3 cases). One case was cyclin D negative. Cytogenetics and fluorescence in situ hybridization detected t(2;12)(p11;p13)/IGK-CCND2 in one of the cyclin D2-positive cases and t(6;14)(p21;q32)/IGH-CCND3 in one of the cyclin D3-positive cases. Moreover, we identified a novel cryptic t(2;14)(p24;q32) targeting MYCN in 2 blastoid MCLs: one negative for cyclin D and one expressing cyclin D3. Interestingly, both cases showed expression of cyclin E. Notably, all 3 blastoid MCLs showed a monoallelic deletion of RB1 associated with a lack of expression of RB1 protein and monoallelic loss of p16. In sum-mary, this study confirms frequent aberrant expression of cyclin D2 and D3 in t(11;14)-negative MCLs and shows a t(11;14)-independent expression of cy-clin D1 in 25% of present cases. Novel findings include cyclin E expression in 2 t(11;14)-negative MCLs characterized by a cryptic t(2;14)(p24;q32) and identification of MYCN as a new lymphoma oncogene associated with a blastoid MCL. Clinically important is a predisposition of t(11;14)-negative MCLs to the central nervous system involvement.     

Over-expression of cyclin D1 in chronic B-cell malignancies with abnormality of chromosome 11q13

Accurate identification of B-cell chronic malignancies is sometimes uncertain, despite careful cytologic and immunophenotypic evaluation. Cytogenetics and molecular biology studies may therefore prove useful, because some of these disorders are associated with nonrandom abnormalities, such as the t(11;14)(q13;q32) translocation and bcl-1 rearrangement mainly observed in mantle-cell lymphoma (MCL). We studied the expression of cyclin D1 in malignant lymphoid cells from the peripheral blood of 32 patients with various B-cell chronic lympho-proliferative disorders, using Northern blot (NB) and RNA in situ hybridization (ISH). Cytogenetic analysis was informative in 18 cases, and most of the missing karyotype data were from typical B-CLL cases where a t(11;14) is unlikely to be found. Over-expression of cyclin D1 mRNA was observed by both NB and ISH in four samples (MCL: two cases; lymphoplasmacytic lymphoma: one case, unclassified B-cell chronic disorder: one case). In each of these cases there was an abnormality of chromosome 11q13, either a t(11;14)(q13;q32) translocation (three cases) or a del(11)(q13) without evidence of chromosome 14 involvement (one case). Cytogenetic and gene rearrangement studies are not available in all institutions and have some technical pitfalls. Because of its close association with bcl-1 rearrangement and/or t(11;14), the demonstration of cyclin D1 mRNA over-expression either by NB, or, more conveniently, by ISH, may represent additional information which could be of help for the identification of B-cell malignancies.     

Chromosome banding studies in Philadelphia chromosome positive myeloid leukaemia.

A cytogenetic study of Ph1 positive myeloid leukaemia in both chronic and acute phases had been made by a chromosome banding technique. The translocation (t(9;22)(q34;q11), designated t(Ph1) was present in the myeloid cells of 43 of 44 patients; the exceptional case had normal number 9 chromosomes and a different translocation (t(19;22)(q13;q11)). A translocation additional to that involving the Ph1 was found as a stable abnormality present in all myeloid cells in 4 patients, chromosome 17 being involved in 2. The association of isochromosome number 17 with blast crisis was confirmed. New data were obtained concerning the significance of duplicated or dicentric Ph1 chromosomes and their relationship with the 9q+ anomaly. Monoclonal origin of Ph1 was confirmed in cases with polymorphic number 22 or 9 chromosomes.     

Cytogenetic abnormalities in childhood acute myeloid leukaemia: a Nordic series comprising all children enrolled in the NOPHO-93-AML trial between 1993 and 2001

Between 1993 and 2001, 318 children were diagnosed with acute myeloid leukaemia (AML) in the Nordic countries. The patient group comprised 237 children < 15 years of age with de novo AML, 42 children < 15 years with Down syndrome (DS) and de novo AML, 18 adolescents 15-18 years of age with de novo AML, and 21 children < 15 years with treatment-related AML (t-AML). The first group was all-inclusive, yielding an annual childhood de novo AML incidence of 0.7/100 000. Cytogenetic analyses were successful in 288 cases (91%), and clonal chromosomal abnormalities were detected in 211 (73%). The distribution of ploidy levels were pseudodiploidy (55%), hyperdiploidy (34%) and hypodiploidy (11%). The most common aberrations (> 2%) were + 8 (23%) (as a sole change in 6.2%), 11q23-translocations, including cryptic MLL rearrangements (22%) [t(9;11)(p21-22;q23) in 11%], t(8;21)(q22;q22) (9.0%), inv(16)(p13q22) (6.2%), -7/7q- (5.2%), and t(15;17)(q22;q12) (3.8%). Except for +8, these abnormalities were rare in group 2; only one DS patient had a t(8;21) and none had 11q23-translocations, t(15;17) or inv(16). In the t-AML group, three cases displayed 11q23-rearrangements, all t(9;11); and there were no t(8;21), t(15;17) or inv(16). Overall, the observed frequencies of t(8;21) and t(15;17) were lower, and frequencies of trisomy 8 and 11q23-translocations higher, than in previous studies. Furthermore, seven abnormalities that were previously reported as only single AML cases were also seen, meaning that der(4)t(4;11)(q26-27;q23), der(6)t(1;6)(q24-25;q27), der(7)t(7;11)(p22;q13), inv(8)(p23q11-12), t(11;17)(p15;q21), der(16)t(10;16)(q22;p13) and der(22)t(1;22)(q21;q13) are now classified as recurrent abnormalities in AML. In addition, 37 novel aberrations were observed, 11 of which were sole anomalies.     

Chromosome 11q rearrangements in B non Hodgkin''s lymphoma

The clinical features, morphology and immunophenotype of 20 cases of B non Hodgkin's lymphoma (B-NHL) with chromosome abnormalities involving 11q13-14 were studied, to determine if this abnormality was closely associated with a specific sub-type of B-NHL. A t(11;14)(q13;q32) was found in 11 cases of intermediately differentiated lymphocytic lymphoma (IDLL). A breakpoint in the major translocation cluster of the BCL-1 locus was found in six of these cases. These patients were male with lymphomatous involvement of the bone marrow, marked splenomegaly and frequently had mucosa associated lymphoid tissue involvement. One patient with IDLL had a t(8;11)(p21;q13) and a rearranged BCL-1 locus, suggesting that this may be a variant of t(11;14)(q13;q32). Diagnoses of IDLL, chronic lymphocytic leukaemia, lymphoplasmacytic lymphoma and monocytoid B cell lymphoma were made in all but one of the remaining cases. These cases had either a translocation involving 11q13-14 and various partner chromosomes or an 11q13 deletion. This study demonstrates that 11q abnormalities occur mainly in a group of low-grade B-NHL of non follicle centre cell lineage.     

Clinical and biologic features of childhood T-cell leukemia with the t(11;14)

Cytogenetic analysis of cells from 622 consecutive patients with newly diagnosed acute lymphoblastic leukemia (ALL) and successful G-banding chromosome studies disclosed seven cases with the t(11;14)(p13;q11) and one with the t(11;14)(p15;q11). Leukemia cells in all eight cases had a T-cell immunophenotype. The t(11;14)(p13;q11) occurred in 6.8% and the t(11;14)(p15;q11) in 1% of T-cell ALL cases (n = 103). The t(11;14) was associated with presenting clinical features typical of T-cell ALL: male predominance (n = 6), age greater than 10 years (n = 3), hyperleukocytosis (white blood cells greater than 100 x 10(9)/L, n = 5), relatively high hemoglobin level (median, 10.8 g/dL), high serum lactic dehydrogenase level (median, 3248 U/L), presence of mediastinal mass (n = 6), and central nervous system leukemia (n = 2). While there were no significant differences in presenting features between T-cell ALL cases with or without the t(11;14), leukemic cells from patients with the translocations were more likely to coexpress CD4 and CD8 antigens (6 of 6 v 35 of 86 cases tested, P less than .05). Adverse events have occurred in six patients: three central nervous system relapses [including the one with t(11;14)(p15;q11)], two secondary acute myeloid leukemia, and one hematologic relapse. Our results indicate that the t(11;14)(p13;q11) occurs exclusively in T-cell malignancies of intermediate- or late-stage thymocyte differentiation. Additional studies are needed to determine the prognostic implications of these translocations.     

Rearrangement of the breakpoint cluster region and expression of P210 BCR-ABL in a "masked" Philadelphia chromosome-positive acute myeloid leukemia

The Philadelphia (Ph) translocation t(9;22)(q34;q11) occurs frequently in chronic myeloid leukemia (CML) but is less common in acute lymphoblastic leukemia (ALL) and rare in acute myeloid leukemia (AML). In most cases of CML and some cases of Ph+ ALL the protooncogene ABL from 9q34 is translocated to the breakpoint cluster region (bcr) of the BCR gene at 22q11 to form a chimeric gene encoding a novel 210-kd protein (P210 BCR-ABL) with enhanced tyrosine kinase activity. In other patients with Ph+ ALL and Ph+ AML, the breakpoint probably occurs in the first intron of the BCR gene; this results in a smaller chimeric gene which encodes a P190 BCR-ABL. We studied a patient with AML (FAB M6) arising de novo who had a "masked" Ph chromosome in association with extensive karyotypic changes. The leukemic cells initially showed rearrangement of the bcr, presence of a hybrid mRNA, and expression of the P210 BCR-ABL. These changes were absent in remission. These results support the concept that the BCR-ABL chimeric gene plays a crucial role in leukemogenesis but suggest that factors other than the position of the breakpoint in the BCR gene determine the lineage of the target cell for malignant transformation.