Small round cell tumor with biphenotypic differentiation and variant of t(21;22)(q22;q12).

A 14-year-old boy presented with a soft tissue swelling on the outer aspect of his left upper arm. Examination of the tumor by light microscopy showed a small round cell tumor with a rare focus of myogenic differentiation. Myogenic differentiation was confirmed on ultrastructural examination by immunohistochemistry and reverse transcriptase polymerase chain reaction (RT-PCR). Conventional G-banding and fluorescent in situ hybridization (FISH) demonstrated a complex variant of t(21;22)(q22;q12). By RT-PCR, the EWS-ERG fusion transcript was defined as type 9e. This tumor was unusual in that it showed characteristics of myogenic and neural differentiation, and contained a rearrangement of the EWS gene consistent with a diagnosis of Ewing's sarcoma. This supports the hypothesis that a class of biphenotypic childhood sarcomas, with features of myogenic and neural differentiation, exists that may be related to the Ewing's sarcoma family of tumors.

Fluorescence in situ hybridization analysis of 25 cases of idiopathic myelofibrosis and two cases of secondary myelofibrosis: monoallelic loss of RB1, D13S319 and D13S25 loci associated with cytogenetic deletion and translocation involving 13q14.

To identify a commonly deleted region of 13q14 in idiopathic myelofibrosis (IMF), we used fluorescence in situ hybridization analysis to test for deletion of the RB1 and BRCA2 genes, and the microsatellite loci D13S319 and D13S25, in a series of 25 patients. A further two patients with myelofibrosis secondary to polycythaemia vera and essential thrombocythaemia with reciprocal 13q translocations were studied in an attempt to further define the CDR. Twenty out of 21 patients with a cytogenetically normal chromosome 13 failed to show allelic loss with any of the four probes. In contrast, all four cases with cytogenetic deletion of 13q14 and both cases with 13q translocations involving 13q14 exhibited loss of RB1, D13S319 and D13S25. Loss of the BRCA2 locus was present in a single case only. Our results indicate that cryptic deletions of the 13q14 in myelofibrosis are rare. In addition, the genetic loss associated with cytogenetic 13q14 deletions or reciprocal translocations involving 13q14 is large and encompasses the gene-rich region around RB1, D13S319 and D13S25.

MLL amplification in acute leukaemia: a United Kingdom Cancer Cytogenetics Group (UKCCG) study.

The MLL gene, located at 11q23, is frequently rearranged in acute leukaemia as either chimaeric fusion genes or partial tandem duplications. We report a series of 12 acute leukaemia cases with apparent amplification of the MLL gene ascertained using fluorescence in situ hybridisation (FISH). Seven cases showed intrachromosomal amplification of MLL, four cases showed extrachromosomal amplification as double minute chromosomes (dmin) and one case had separate subclones with dmin and homogenously staining region (hsr). Southern blot analysis of the MLL gene showed MLL gene rearrangement in three of the 10 successful cases. These cases do not naturally fall into either of the two recognised categories of MLL rearrangement and may represent a third variety of MLL gene abnormalities.

Acute monocytic leukemia with a novel 10;11 rearrangement resolved by fluorescence in situ hybridization.

Fluorescence in situ hybridization analysis in an adult with acute monocytic leukemia revealed the complex nature of a rearrangement between chromosomes 10 and 11, which resulted in disruption of the MLL gene. Using a combination of chromosome 10 and 11 paints, a 10 centromere-specific sequence, and a probe for the MLL locus at 11q23, the rearrangement was deduced to have involved a reciprocal translocation between chromosomes 10 and 11, followed by an inversion within the short arm of the derivative 10. To our knowledge, this novel rearrangement has not been described previously.

Cytogenetically cryptic AML1-ETO and CBF beta-MYH11 gene rearrangements: incidence in 412 cases of acute myeloid leukaemia.

The rearrangements t(8;21)(q22;22) and inv(16)(p13q22) are two of the most frequently seen in acute myeloid leukaemia (AML), accounting for 8% and 4% of cases respectively. Detection of these abnormalities is important for disease management as both are associated with good responses to conventional chemotherapy and prolonged disease-free survival. Recent reports using reverse transcriptase polymerase chain reaction (RT-PCR) suggest that significant proportions of AML cases without a visible t(8;21) or inv(16) show expression of an abnormal fusion gene transcript and, consequently, they could not be detected using conventional cytogenetic analysis alone. We present here a four centre study involving 412 cases of AML screened using both standard cytogenetics and RT-PCR for AML1-ETO and CBF beta-MYH11. We detected a cytogenetic t(8;21) in 31 out of 412 (7.5%) cases and an inv(16) or t(16;16) variant in 27 out of 412 (6.6%) cases. RT-PCR detected only two cases (0.5%) of cryptic t(8;21) and no instances of cryptic inv(16). Both cryptic t(8;21) cases had the classic M2 FAB morphology for this type of disease. Our data concur with the established FAB type distribution of the rearrangements and indicate that cryptic t(8;21) and inv(16) may be much less frequent than reported elsewhere.

Consistent fusion of MOZ and TIF2 in AML with inv(8)(p11q13).

We have recently cloned the inv(8)(p11q13) in a patient with acute myeloid leukemia (AML), and demonstrated a fusion between the MOZ and TIF2 genes at 8p11 and 8q13, respectively. We have partially characterized a further case of AML with the same karyotypic abnormality. Rearrangements were detected by Southern blotting with a TIF2 probe that was close to the breakpoint in the original inv(8) case and with a MOZ probe corresponding to the breakpoint cluster region in the t(8;16) (p11;p13). These findings indicate the existence of breakpoint cluster regions within both genes and demonstrate that the MOZ-TIF2 fusion is consistently associated with the inv(8)(p11q13).

Trisomy 15 associated with loss of the Y chromosome in bone marrow: a possible new aging effect.

Trisomy 15 as a single autosomal abnormality is a rare finding in hematological disorders and has not as yet been associated with any specific disease type. We report 20 cases of trisomy 15 observed in the bone marrow of patients referred for a suspected hematological malignancy. Most patients were elderly, and a marked male predominance was evident. Aneuploidy for the Y chromosome was observed in addition to +15 in 11 out of 15 male patients. A myelodysplastic disorder (MDS) was confirmed in six cases, and acute myeloid leukemia (AML) in one. There was no evidence of malignant hematological diseases in the remaining 13 patients. We propose that there may be an association between loss of the Y chromosome and trisomy 15 and that trisomy 15, like missing Y, may not always be a marker of malignancy, but may reflect an underlying age effect. The possibility that its presence may herald the development of a malignant condition cannot, however, be excluded.

Hematologic malignancies with t(4;11)(q21;q23)--a cytogenetic, morphologic, immunophenotypic and clinical study of 183 cases. European 11q23 Workshop participants.

A total of 183 hematologic malignancies with t(4;11)(q21;q23), including five variant translocations, were collected by the Workshop. Clinical, morphologic and immunophenotypic features were compiled, and karyotypes with variant t(4;11) or secondary chromosomal aberrations were reviewed. All cases were acute leukemias (AL): 173 acute lymphoblastic leukemias (ALL), six acute myeloid leukemias (AML), three unclassifiable AL, and one biphenotypic AL. Ten patients had treatment-associated AL. Females were overrepresented (104 vs 79) and the age distribution was clearly nonrandom; 34% of the cases occurred in infants below the age of 12 months. The remaining AL were evenly distributed among the other age groups, with the oldest patient being 79 years old. An increased white blood cell count (WBC) was reported in more than 90% of the cases, with hyperleukocytosis (> or =100 x 10(9)/l) in 64%. Additional chromosomal changes were detected in 55 (30%) cases, most often gain of the X chromosome, i(7)(q10), and trisomy 8, with frequent breakpoints in 1p36, 1q21, 7q10, 11p15, 12p13, 17p11, and 17p10. All recurrent secondary changes resulted in genomic imbalances, in particular gains of 1q, 7q, 8, and X and losses of 7p and 17p. Event-free and overall survival (EFS and OS) could be ascertained in 170 and 171 patients, respectively. Kaplan-Meier estimates of EFS and OS showed no differences with regard to gender, WBC, or presence of secondary chromosomal abnormalities, and there was no increase of EFS or OS among the 55 cases that had undergone bone marrow transplantation. However, age had an important prognostic impact, with significantly (P < 0.0001) longer EFS and OS in children 2-9 years old than among infants and younger children, patients aged between 10 and 39 years and older adults.

Two cases of inv(8)(p11q13) in AML with erythrophagocytosis: a new cytogenetic variant.

We describe two patients with acute myeloid leukaemia (AML) associated with erythrophagocytosis and a pericentric inversion of chromosome 8, inv(8)(p11q13). The haematological features were indistinguishable from those of patients with the t(8;16) syndrome and its variants. Our observations emphasize the importance of the breakpoint at 8p11 and the possible involvement of the MOZ gene in all these cases.

Trisomy 21 associated transient neonatal myeloproliferation in the absence of Down's syndrome.

Although usually associated with Down's syndrome, transient neonatal myeloproliferation (TMD) can occur in the absence of a constitutional trisomy 21. This report describes two such cases, both of whom had a trisomy 21 restricted to clonal cells. Unlike in previous such reported cases, spontaneous morphological, cytogenetic, and molecular remission in both cases was followed by re-emergence, in one case, of an evolved clone with a more malignant phenotype which required pharmacological intervention. Awareness that trisomy 21 bearing leukaemia in the neonatal period can be transient even in the absence of Down's syndrome is important to prevent unnecessary treatment. Equally, such cases require indefinite follow up as a proportion may have a recurrence which may require treatment.

Cytogenetic abnormalities and their prognostic significance in idiopathic myelofibrosis: a study of 106 cases.

The prognostic significance of cytogenetic abnormalities was determined in 106 patients with well-characterized idiopathic myelofibrosis who were successfully karyotyped at diagnosis. 35% of the cases exhibited a clonal abnormality (37/106), whereas 65% (69/106) had a normal karyotype. Three characteristic defects, namely del(13q) (nine cases), del(20q) (eight cases) and partial trisomy 1q (seven cases), were present in 64.8% (24/37) of patients with clonal abnormalities. Kaplan-Meier plots and log rank analysis demonstrated an abnormal karyotype to be an adverse prognostic variable (P<0.001). Of the eight additional clinical and haematological parameters recorded at diagnosis, age (P<0.01), anaemia (haemoglobin < or = 10 g/dl: P<0.001), platelet (< or = 100 x 10(9)/l, P<0.0001) and leucocyte count (> 10.3 x 10(9)/l; P=0.06) were also associated with a shorter survival. In contrast, sex, spleen and liver size, and percentage blast cells were not found to be significant. Multivariate analysis, using Cox's regression, revealed karyotype, haemoglobin concentration, platelet and leucocyte counts to retain their unfavourable prognostic significance. A simple and useful schema for predicting survival in idiopathic myelofibrosis has been produced by combining age, haemoglobin concentration and karyotype with median survival times varying from 180 months (good-risk group) to 16 months (poor-risk group).

The translocation t(8;16)(p11;p13) of acute myeloid leukaemia fuses a putative acetyltransferase to the CREB-binding protein.

The recurrent translocation t(8;16)(p11;p13) is a cytogenetic hallmark for the M4/M5 subtype of acute myeloid leukaemia. Here we identify the breakpoint-associated genes. Positional cloning on chromosome 16 implicates the CREB-binding protein (CBP), a transcriptional adaptor/coactivator protein. At the chromosome 8 breakpoint we identify a novel gene, MOZ, which encodes a 2,004-amino-acid protein characterized by two C4HC3 zinc fingers and a single C2HC zinc finger in conjunction with a putative acetyltransferase signature. In-frame MOZ-CBP fusion transcripts combine the MOZ finger motifs and putative acetyltransferase domain with a largely intact CBP. We suggest that MOZ may represent a chromatin-associated acetyltransferase, and raise the possibility that a dominant MOZ-CBP fusion protein could mediate leukaemogenesis via aberrant chromatin acetylation.

Acute lymphoblastic transformation of essential thrombocythaemia.

Essential thrombocythaemia is a myeloproliferative disorder which may transform to acute myeloid leukaemia, especially following therapy with alkylating agents or radioactive phosphorus. We describe the rare occurrence of acute lymphoblastic leukaemia transformation in a patient with known essential thrombocythaemia.

Karyotypic and ras gene mutational analysis in idiopathic myelofibrosis.

Karyotypic analysis was performed in a total of 69 patients with well-characterized idiopathic myelofibrosis. Karyotypic abnormalities were detected in 46% of cases examined during the chronic phase (29/63); with three abnormalities, del(13q), del(20q) and partial trisomy 1q, accounting for 75% of all abnormalities at diagnosis. The absence of del(5q), trisomy 8 and 21, as well as the rarity of monosomy 7, contrasts with pooled published data and may reflect our exclusion of closely related disorders, in particular MDS with fibrosis. Chromosomal aberrations increased to approximately 90% (8/9) in patients analysed during acute transformation. Mutational activation of codons 12, 13 and 61 of N-, Ha- and Ki-ras genes were assessed by polymerase chain reaction and hybridization with synthetic non-radioactive digoxigenin-labelled probes. Three mutations were detected in samples of peripheral blood DNA taken from 50 patients during the chronic phase of their disease: one N12 Asp (GGT-->GAT) and two N12 Ser (GGT-->AGT) mutations. The results from this study indicate that karyotypic abnormalities are present in at least 29% of cases at diagnosis and that del(13q), del(20q) and partial trisomy 1q are the most frequent findings. Ras mutations were relatively infrequent (6%) and appeared restricted to the N-ras gene. Karyotypic analysis at diagnosis was found to be of prognostic significance.

Chromosomes in childhood acute lymphoblastic leukaemia: karyotypic patterns in disease subtypes.

To define further the clinical importance of cytogenetic analysis in acute lymphoblastic leukaemia (ALL) a prospective study was performed on 139 unselected children. Analyses were considered adequate in 104, of whom 35 were normal and 69 had clonal abnormalities. Abnormalities were categorised according to banded chromosome analysis as well as chromosome count. Karyotypes were correlated with clinical and laboratory features at diagnosis and with survival. Of the successful analyses, thirty five (34%) children had no abnormalities; this group contained an excess of T cell disease. Twenty five (24%) had a "characteristic" hyperdiploid karyotype and as a group had lower presenting white counts, a tendency to CD10, and periodic acid schiff positivity of the blast cells and smaller spleens. None was an infant and only one was over 10 years old. Seven (7%) children with t(9; 22), t(8; 14), or t(4; 11) translocations were grouped together as "specific" translocations. Collectively they had a significantly worse prognosis than the remainder. Nine children developed central nervous system relapse, six of whom had either t(4; 11) or abnormalities of 9p or 19p. A descriptive classification taking into account chromosome bonding pattern is cytogenetically more appropriate and may be more clinically useful than grouping children simply by chromosome number. As knowledge and techniques improve, the classification of cytogenetic abnormalities in ALL will need to be kept under frequent review.

Chromosome studies in eleven colorectal tumors.

Cytogenetic analysis is presented on seven freshly derived colorectal tumors and four established cell lines (SW 742, SW 480, SW 948, and HT 29). No chromosome change was common to all tumors, although previous nonrandom findings were confirmed. Single chromosome abnormalities were identified in two cases, 47,XX,+i(7p) and 46,XX,-17,+der(17),t(17;?)(p;?), and their relevance to tumor origin and development is discussed. The association of i(8q) with tumors of the rectosigmoidal region is confirmed, and it is suggested that other rearrangements involving loss of 8p may have the same association. Abnormalities resulting in loss of 20p and duplication of 20q, not previously reported as a nonrandom change, were seen in seven out of 11 cases.

Monosomy 7, leukaemia and immunoglobulin heavy chain gene rearrangement.

We describe the haematological findings and clinical course of a 15-year-old male who presented with a spontaneous acute lymphoblastic leukaemia. The lymphoid origin of the leukaemia was supported by cell surface antigen studies and immunoglobulin heavy chain gene analysis. Bone marrow karyotype was simple monosomy 7 and the lymphoblasts expressing the myeloid associated antigen CD 33. Both of these features have been previously shown to indicate a poor prognosis. The findings in this patient support a previous hypothesis that monosomy 7 can arise at the stem cell level.

Methotrexate and bone marrow metaphases.

The efficacy of a methotrexate (MTX) block/thymidine release synchronization technique has been assessed in bone marrow cultures from patients with acute nonlymphocytic leukemia and myelodysplasia. In contrast to cultures of stimulated lymphocytes from normal individuals, no improvement in mitotic index (MI) or metaphase quality could be detected using this technique. Demonstration of an unchanged level of division in bone marrow cultures in the presence of MTX suggests that the technique is unsuitable for synchronization purposes in this tissue. The influence of preincubation prior to MTX exposure and duration of exposure to colcemid on MI and metaphase quality have also been examined.