Monosomy 20 as a pointer to dicentric (9;20) in acute lymphoblastic leukemia

Twenty new cases of acute lymphoblastic leukemia (ALL) with the dicentric chromosome dic(9;20)(p1113;q11) are presented. This chromosomal abnormality is difficult to identify from G-banding alone. It masquerades as monosomy 20 and is only accurately identified by fluorescence in situ hybridization (FISH). Monosomy 20 was found in 59/2790 patients with successful karyotypes entered to the Leukaemia Research Fund/UK Cancer Cytogenetics Group Karyotype Database in ALL (LRF/UKCCG Karyotype Database). FISH revealed dic(9;20) in 20/25 cases with available material. Extra copies of chromosome 21 were found in 8 of the 20 cases. Patients were 14 females and six males, aged 1-32 years (median 4 years), with leukocyte counts of 2-536 (median 23) x 109/l and immunophenotypes of common or pre-B ALL (17 cases), T-ALL (one case) or unknown (two cases). Four patients relapsed at 2, 22, 28 and 47 months and two died at 49 and 63 months (median follow-up 37 months). FISH studies on the remaining five patients showed one with monosomy 20 and four with other rearrangements of the chromosome. This study has increased the number of reported cases of dic(9;20) from 17 to 37. It has identified dic(9;20) in one case of T-ALL and shows an association of this translocation with trisomy 21.

Investigation of clonal involvement of myeloid cells in Philadelphia-positive and high hyperdiploid acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) with a high hyperdiploid clone has a good prognosis for both childhood and adult patients while patients with Philadelphia-positive (Ph) ALL do badly at all age groups. It has been suggested that different responses to treatment might be related to the cell of origin of the leukemia with 'stem cell' cases responding less well than those arising in a lymphoid committed progenitor cell. The clonal involvement of different cell lineages in 12 patients with acute lymphoblastic leukemia has been examined by applying fluorescence in situ hybridization (FISH) to detect chromosomal abnormalities in bone marrow cells previously identified by morphology and/or immunology. The karyotype of the malignant clone was either high hyperdiploid or Philadelphia translocation (Ph) positive with a breakpoint in the minor breakpoint cluster region of the BCRgene (m-BCR) or in the major breakpoint cluster region of the BCR gene (M-BCR). The high hyperdiploid clone, in each case, was found in cells of the B-lymphoid (CD19+) lineage but not in T cells (CD3+) or in cells of the myeloid (CD13+) or erythroid (glycophorin A+) lineages, indicative of a lymphoid committed progenitor cell. Heterogeneity of lineage involvement was found in Ph+ ALL: the m-BCR Ph+ clone was found in lymphoid/blast cells but not in neutrophils or eosinophils. In contrast both M-BCR Ph+ clones were detected in myeloid as well as lymphoid lineages, indicative of a stem cell origin.

The importance of cytogenetics and associated molecular techniques in the management of patients with leukaemia

The cytogenetic analysis of haematological malignancies plays a major role in diagnosis. A large number of non-random chromosomal abnormalities are associated with specific types of leukaemia. Often, the cytogenetic result provides the definitive diagnosis. The recent developments in molecular cytogenetic technologies, in association with conventional cytogenetic analysis, have improved the accuracy of the results and led to the finding of new chromosomal abnormalities in leukaemia. Patients may be monitored by cytogenetics, molecular techniques and/or fluorescence in situ hybridization (FISH) during the course of their management, for evidence of minimal residual disease. These techniques also provide a useful method for monitoring patients following bone marrow transplantation, particularly when the patient and the donor are of the opposite sex. The cytogenetic result is an independent prognostic indicator, with certain karyotypes associated with a good prognosis, although others indicate a poor outcome.

Abnormalities of the ETV6 gene occur in the majority of patients with aberrations of the short arm of chromosome 12: a combined PCR and Southern blotting analysis

Involvement of the ETV6 gene, located at 12p13, has been investigated in 20 patients with an abnormality of the short arm of chromosome 12 (abn 12p) detected cytogenetically. Patients in the study had c/pre-B acute lymphoblastic leukemia (ALL) (nine children and three adults), T-ALL (three adults), acute myeloid leukemia (AML) (two adults), biphenotypic acute leukemia (Bip-L) (one adult), myelodysplasia (MDS) (one adult) and chronic myelomonocytic leukemia (CMML) (one child). Abnormalities of 12p comprised deleted (del)(12p) alone (seven cases), add(12p) alone (seven cases), del(12p) and add(12p) (one case) and balanced translocations of 12p to 1p13, 1q31, 10q11, 14q11 and 15q15 (one case of each). A novel, exon-specific RT-PCR assay identified breakpoints in ETV6 in nine of 19 cases, and showed breakpoints in intron 5 (seven cases of children with c-ALL), in intron 4 (in one adult with Bip-L) and in intron 2 (in one adult with AML). RT-PCR for the ETV6/AMLI fusion (tested in 19 cases) was positive using standard primers in five cases (four of which had shown rearrangements in intron 5) and occurred as a variant fusion in a sixth case (also positive for a rearrangement in intron 5) using 3' RACE PCR. Southern blotting confirmed rearrangements in intron 5 in the five cases available for analysis and revealed a rearrangement in intron 5 in one of 10 cases with no evidence of intron 5 involvement by RT-PCR. Rearrangements in intron 5 of ETV6 were found in eight of nine cases of children with c-ALL of which six carried the ETV6/AMLI fusion. Heterozygosity within intron 5 (revealed by the genomic probe B1) was found in seven of 11 cases tested. Deletion of one allele was indicated in three cases with del(12p) and one case with add(12p). This study, using a combination of ETV6 exon-specific RT-PCR, RT-PCR for ETV6/AMLI and Southern blotting has shown that rearrangement and/or deletion of ETV6 may occur in up to 70% of patients with abn 12p. Furthermore, 90% of children in this study with an abn 12p and c-ALL, carried a rearrangement of ETV6 in intron 5.

Trisomy 13 and myeloid malignancy--characteristic blast cell morphology: a United Kingdom Cancer Cytogenetics Group survey

We retrospectively report data on 28 patients with haematological malignancy and trisomy 13 (25 cases) or tetrasomy 13 (three cases) as the primary acquired cytogenetic change. Peripheral blood and/or bone marrow morphology was reviewed in 25/28 cases and the final diagnosis was as follows: AML M0 (11), AML M1 (6), AML M2 (2), AML M4 (2), AML M5b (1), AML M6 (1), RAEB-t (3), RAEB (1), RA (1). All three cases with tetrasomy 13 had AML M0. Characteristic small hand-mirror blasts with cytoplasmic blebs and tails and scanty small granules were seen in 13/25 cases and 18/25 cases had small blasts which could easily be mistaken for lymphoblasts. Trilineage dysplasia was present in 8/28 cases. Median patient survival was 3 months. We conclude that trisomy 13 is particularly associated with acute myeloid leukaemia with minimal differentiation (AML MO), often has distinctive morphological features, and has a poor prognosis.

Derivative chromosomes of 11q23-translocations in hematologic malignancies. European 11q23 Workshop participants

Cytogenetic and molecular analyses of 11q23/MLL positive hematologic malignancies show that der(11) encodes the critical 5'MLL/3'partner gene transcript. The role of der(non-11) bearing the 5'partner/3'MLL fusion is less certain. The cytogenetic evidence for der(11) as the critical partner was investigated. Among 1680 cases (550 workshop and 1130 published) 31 cases displayed a three-way (29 cases) or four-way (two cases) translocation and 26 had only one of the derivatives. The critical junction created by t(11;n)(q23;n) was seen in all six cases of t(1;11)(q21;q23), in both cases of t(6;11)(q27;q23), in all six cases of t(11;19)(q23;p13), in nine of 11 cases with t(4;11)(q21;q23) and in 17 of 20 cases with t(9;11)(p21-22;q23). These findings support the evidence for der(11) encoding the critical leukemogenic fusion transcript. In contrast, additional change involving duplication of one of the derivatives resulted in duplication only of the non-critical der(non-11) as follows: +der(4)t(4;11)(q21;q23) [9/553], +der(6)t(6;11)(q27;q23) [3/61], +der(9)t(9;11)(p21-22;q23) [5/291] and +der(19)t(11;19)(q23;p13) [6/164]. A literature search of other neoplastic disorders showed that either derivative may be duplicated. Duplication of the non-critical derivative is the norm in AML patients with t(8;21)(q22;q22) or t(15;17)(q22;q12-21). We suggest that the genomic imbalance, rather than over-expression of the noncritical 5'partner/3'MLL, is likely to be the important outcome.

Hematological malignancies with t(9;11)(p21-22;q23)--a laboratory and clinical study of 125 cases. European 11q23 Workshop participants

This paper reports clinical and cytogenetic data from 125 cases with t(9;11)(p21-22;q32) which were accepted for a European Union Concerted Action Workshop on 11q23. This chromosome abnormality is known to occur predominantly in acute myeloid leukemia (AML) FAB type M5a and less often in AML M4; in this series it was also found to occur, uncommonly, in other AML FAB types, in childhood acute lymphoblastic leukemia (ALL) (nine cases), in relatively young patients with myelodysplastic syndrome (MDS) (five cases), acute biphenotypic leukemia (two cases), and acute undifferentiated leukemia (one case). All age groups were represented but 50% of the patients were aged less than 15 years. The t(9;11) was the sole abnormality in 57 cases with AML; trisomy 8 was the most common additional abnormality (23 cases, including seven with further abnormalities), and 28 cases had other additional abnormalities. Among the t(9;11)+ve patients with AML, the white cell count (WBC) and age group were significant predictors of event-free survival; central nervous system (CNS) involvement or karyotype class (sole, with trisomy 8, or with other), also contributed to prognosis although our data could not show these to be independent factors. The best outcome was for patients aged 1-9 years, with low WBC, and with absence of CNS disease or presence of trisomy 8. For patients aged less than 15 years, the event-free survival for ALL patients was not significantly worse than that of AML patients.

The t(10;11)(p12;q23) translocation in acute leukaemia: a cytogenetic and clinical study of 20 patients. European 11q23 Workshop participants

The clinical, haematological and cytogenetic data for 20 patients with an acquired abnormality of 11q23 and 10p have been reviewed at this workshop. Patients predominantly presented with de novo AML M5a and the most common cytogenetic finding was an inversion of part of the long arm of chromosome 11 followed by a translocation between 11q and 10p. Band p12 represented the most common breakpoint on chromosome 10. The t(10;11) subgroup defined a subset of younger 11q23 patients, the majority of whom achieve a first complete remission despite the differing treatment regimens.

Hematological malignancies with a deletion of 11q23: cytogenetic and clinical aspects. European 11q23 Workshop participants

Balanced translocations of 11q23 are associated with specific clinical features and a poor outcome, but the relevance of deletions involving 11q23 is not clear. Fifty-seven patients with this deletion were collected by the Workshop, 30 had terminal and 27 had interstitial deletions. Twenty-seven patients had acute lymphoblastic leukemia (ALL), 16 had acute myeloid leukemia (AML), one had acute biphenotypic leukemia, one had acute undifferentiated leukemia and 12 had myelodysplastic syndrome (MDS). ALL patients had a median age of 7 years, median white blood cell count (WBC) of 15 x 10(9)/l, and 10/24 had common ALL. AML patients had a median age of 23 years, a median WBC of 49 x 10(9)/l, and 9/16 had M4 or M5. MDS patients were all adult, median age of 69 years, median WBC of 3 x 10(9)/l, and 7/12 had refractory anemia. The clinical outcome depended on diagnosis: children with ALL had a better prognosis (4/16 relapsed, one died) than AML patients; all adults and children with AML and 5/12 MDS patients died. Fluorescence in situ hybridization (FISH) identified 3 del(11q23) as translocations or insertions. Molecular studies revealed a MLL rearrangement in 8/10 patients. Because the involvement of MLL might be of prognostic relevance, identification of a del(11q23) should be an indication for FISH and molecular studies.

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.

The translocations, t(11;19)(q23;p13.1) and t(11;19)(q23;p13.3): a cytogenetic and clinical profile of 53 patients. European 11q23 Workshop participants

The EU Concerted Action Workshop on 11q23 Abnormalities in Hematological Malignancies collected 550 patients with abnormalities involving 11q23. Of these, 53 patients had a translocation involving chromosome 11, breakpoint q23, and chromosome 19, breakpoint p13. Karyogram review enabled each patient to be further defined as t(11;19)(q23;p13.1) (21 patients) or t(11;19)(q23;p13.3) (32 patients). There was a marked difference between the type of banding and the translocation identified: t(11;19)(q23;p13.1) was detected predominantly by R-banding, whereas t(11;19)(q23;p13.3) was detected almost solely by G-banding. Additional change was extremely rare in patients with t(11;19)(q23;p13.1) but occurred in nearly half of the patients with t(11;19)(q23;p13.3). Patients with t(11;19)(q23;p13.1) all had leukemia of a myeloid lineage, mostly acute myeloid leukemia (AML), and were predominantly adult. In contrast patients with t(11;19)(q23;p13.3) had malignancies of both myeloid and lymphoid lineage and were mainly infants less than 1 year old. The survival of both groups of patients was generally poor, over 50% of t(11;19)(q23;p13.1) patients died within 2 years of diagnosis and the median survival of acute lymphoblastic leukemia (ALL) patients with t(11;19)(q23;p13.3) was 17.6 months.

Ten novel 11q23 chromosomal partner sites. European 11q23 Workshop participants

The MLL gene located at 11q23 has been described as a 'promiscuous' gene due its involvement with a large number of genetic partners. The EU Concerted Action Workshop on 11q23 provided 550 cases for study of which 82 showed abnormalities which did not involve the established translocations or deletion of 11q23. In these 'other' cases, which included inversions and duplications, 11q23 was found to be involved with 25 chromosome partners of which 10 had not been previously reported. These were 1q31, 4p11, 6q13, 8q21, 10q22, 10q25, 11q11, 11q21, 13q34 and 18q23. This study demonstrated the value of the Workshop, in confirming the diversity of chromosomal partner sites involved with 11q23 and in the identification of new partners.

General Report on the European Union Concerted Action Workshop on 11q23, London, UK, May 1997

Seventeen cytogenetic laboratories in eight European countries contributed karyotypic, hematological, clinical and follow-up data from 550 patients with an acquired abnormality of 11q23. The patients had acute lymphoblastic leukemia (254), acute myeloid leukemia (250), unspecified, undifferentiated, biphenotypic acute leukemia or myeloproliferative disorder (18 cases together), or myelodysplastic syndrome (MDS) (28). The patients were classified by cytogenetic subgroup as t(4;11) (183 cases), t(6;11) (30) cases), t(9;11) (125 cases), t(10;11) (20 cases), t(11;19) (53 cases), 'other' abnormalities of 11q23 (82 cases) and del(11)(q23) (57 cases). Manuscripts were prepared on each cytogenetic subgroup, on MDS, on secondary hematological malignancies (40 cases) and on 11q23-translocation derivatives. For each subgroup the following aspects were investigated: associated clinical features, additional karyotypic change, distribution between hematological subtypes and between different age groups, prognosis at different age groups, and the impact of bone marrow transplantation on survival. The Workshop confirmed some previous findings from smaller studies, challenged others, identified new chromosomal partners and threw new light on less well documented aspects of 11q23 malignancies. The large number of cases investigated in a coordinated manner gives authoritative support to the findings. The Workshop thus demonstrates the value of collaborative European studies in the cytogenetics of malignancy.

The t(6;11)(q27;q23) translocation in acute leukemia: a laboratory and clinical study of 30 cases. EU Concerted Action 11q23 Workshop participants

Thirty patients representing 5.5% of those collected by the 11q23 workshop had a t(6;11)(q27;q23). They included 27cases of acute myeloid leukemia (AML) (M1, three cases; M2, two cases; M4, nine cases; M4/M5, one case; M5, 12 cases) of age range 3-72 years and three cases of acute lymphoblastic leukemia (ALL) (B-lineage ALL, two cases; T-ALL, one case) of age range 0.5-13 years. In 20 cases the t(6;11) was the sole abnormality. In 10 cases the recurrent additional abnormalities were extra copies of chromosomes 8, 19, 21, or the der(6). Translocation t(6;11) was identified by cytogenetics alone in 13 cases. In three cases it was confirmed by fluorescence in situ hybridization (FISH) using whole chromosome paints (wcps) 6 and 11. In a further 14 cases involvement of MLL was demonstrated by FISH, by reverse transcriptase polymerase chain reaction (RT-PCR), by Southern blotting (SB) or by a combination of these methods. One case had a direct insertion of 11 into 6-dir ins(6;11)(q27;q13q23). Molecular investigations showed that one case had a 3' deletion of MLL. The median overall survival for the patients was 12 months, indicating a poor prognosis for patients with a t(6;11) translocation.

Secondary acute leukemia and myelodysplastic syndrome with 11q23 abnormalities. EU Concerted Action 11q23 Workshop

Forty of the 550 patients (7%) entered to the 11q23 Workshop had secondary (s) acute lymphoblastic leukemia (nine cases), s-acute myeloid leukemia (25 cases, predominantly of FAB type M5), s-acute leukemia unspecified (one case) or s-myelodysplastic syndrome (five cases) following treatment for a primary malignancy. Breast cancer (12 cases) and non-Hodgkin's lymphoma (eight cases) were the most frequent primaries. Twenty-three patients had been treated with either an epipodophyllotoxin (seven patients) or an anthracycline (10 cases) or both (four cases) frequently combined with alkylating agents (12 cases) and with radiotherapy (six cases). Two further patients had alkylating agents and two had radiotherapy alone. Time between diagnosis of the primary and secondary malignancy was between 10 months and 22 years (median 24 months). The incidence of secondary malignancies in 11q23 subgroups was: t(11;19)(q23;p13.1) (33%), t(9;11) (8%), t(4;11) (5.5%), t(10;11)(5%), t (6;11) (3%), del11q23(2%) and 10 patients had a rare 'other' abnormality. No associations were seen between type of prior malignancy and 11q23 subgroup, or between prior malignancy and leukemia subtype. Remission, when achieved (32 patients), was short (median 5 months). Two patients survived following a bone marrow transplant for s-leukemia and s-myelodysplastic syndrome.

Myelodysplastic syndromes associated with 11q23 abnormalities. European 11q23 Workshop participants

Most hematological neoplasms associated with 11q23 chromosomal rearrangement have been cases of acute lymphoblastic or acute myeloid leukemia. Although cases of myelodysplastic syndrome (MDS) are a minority, these syndromes should also be recognized as part of the spectrum of hematological disorders associated with 11q23 rearrangement. In this series of 550 patients with such rearrangement there were 28 (5.1%) who presented with MDS. A further five patients had a history of MDS but had evolved to AML by the time cytogenetic analysis was first undertaken. There were thus a total of 33 patients (6.0%) with an 11q23 abnormality whose initial presentation was as MDS. Of these 33 patients, a quarter (seven patients) were cases of secondary (therapy-related) MDS. Complex karyotypes and other poor prognosis chromosomal abnormalities such as -7 and 7q- were common and were not confined to secondary cases. The likelihood of presentation as MDS differed between different cytogenetic categories. The 28 patients in whom cytogenetic analysis was performed at presentation as MDS showed a wide age distribution, from 1 to 82 years; there were four children, two of 1 year of age. All FAB types of MDS were represented. Median survival was only 19.1 months. Leukemic transformation occurred in five patients including one case of transformation to a biphenotypic M5a/T-lineage acute leukemia.

Fluorescence in situ hybridization reveals trisomy 2q by insertion into 9p in hepatoblastoma

Cytogenetics and fluorescence in situ hybridization (FISH) of a hepatoblastoma are presented. The results of standard chromosome analysis were as follows: 47,XY,+2,add(4)(q35),-9,+20[10]. FISH with the use of whole-chromosome paints revealed partial trisomy of the long arm of chromosome 2 by insertion into chromosome 9. Comparison of the G-banded metaphases with metaphase FISH led to a reinterpretation of the karyotype as: 47,XY,add(4)(q35),der(9)ins(9;2)(p22;q?21q?25),+20. This case supports previous observations that the critical region of trisomy 2 lies between 2q21 and 2qter and shows how partial trisomy 2q may evade detection in G-banded metaphases.

[2q21-qter trisomy in hepatoblastoma]

Cytogenetic findings and fluorescens in situ hybridization results of a hepatoblastoma of a boy of two and half years of age are presented. Cytogenetic analysis and fluorescens in situ hybridization technique were performed using tumor tissue obtained by biopsy. The direct culture was harvested after 16 hour colcemid treatment. The results of G-banding were as follows: 47,XY,add(4) (q26),-9,+20. There were considerable variation in the degree of condensation and hence in the number of visible G-bands both between metaphases and between homologous chromosomes in the same metaphases. Fluorescens in situ hybridisation were carried out by whole chromosome painting probes: 2,3,4, and 20. The karyotype of the malignant cells was adjusted accordingly: 47,XY,der(4)(q35),dir ins(9;2)(p22;q?21q?25),+20. The results confirm the most common primary chromosome abnormalities in hepatoblastoma are the following: trisomy 2, trisomy 20 and 4q structural rearrangement. Fluorescens in situ hybridization confirms the importance of trisomy 2q21-qter in hepatoblastoma. Authors recommend the use of fluorescens in situ hybridization to correct any tumor karyotype with difficult or ambiguous chromosome morphology.

Molecular detection of minimal residual disease in adult and childhood acute lymphoblastic leukaemia reveals differences in treatment response

Immunoglobulin heavy chain gene (IgH gene) rearrangements are found in the majority of patients with B lineage acute lymphoblastic leukaemia (ALL). Two hundred and three bone marrow samples from 54 patients (33 adults and 21 children) were analysed by PCR within specific time-points after diagnosis (ie 1, 2-3, 4-6 and 7-12 months) using FR1 and JH primers (fingerprinting with a sensitivity > or =1:5 x 10[3]). CDR3-derived allele specific oligoprimers (ASO to achieve a sensitivity between 1:10[4] and 1:10[5]) were applied to 12 children and 18 adults, while size of CDR3 region, oligoclonality and background problems prevented their application to the remaining patients. All patients were followed clinically for > or =24 months. Thirty adults and 16 children presented as newly diagnosed ALL, while the remaining eight patients were analysed in first or subsequent relapse. Patients destined to relapse showed a higher proportion of positive tests (> or =50%), particularly after 1 month, than in the remission group, irrespective of age. Among patients staying in remission, a decrease in MRD-positive tests occurred during the first 12 months in both age groups. However, the proportion of positive tests dropped below 15% at a later stage in adults (4-6 months) than in children (2-3 months). Among children, only patients destined to relapse were MRD positive beyond 1 month, with the exception of only one patient, still positive at 2-3 months in the remission group. The difference in MRD positivity between relapse and remission patients was statistically significant in children (P < 0.03) at any time of testing, but only at 4-6 months in adults (P < 0.01). These data suggest that resolution of MRD in ALL occurs more rapidly in children compared to adults, particularly within the first 6 months. Children and adults, studied in first or subsequent relapse, showed a higher proportion of positive tests during reinduction compared to newly diagnosed patients.

Cytogenetics adds independent prognostic information in adults with acute lymphoblastic leukaemia on MRC trial UKALL XA. MRC Adult Leukaemia Working Party

Cytogenetic classification of 350 adults with acute lymphoblastic leukaemia on MRC UKALL XA trial showed the following statistically significant associations: t(9;22) (11%) increased with increasing age and leucocyte counts (WBC) and most had a C/pre-B immunophenotype. t(4;11) (3%) was associated with higher WBCs, increasing age and null immunophenotype. Other abnormalities of 11q (abn11q) (4%) were associated with male sex and T-cell ALL. High hyperdiploidy (7%) and abn9p (5%) decreased with increasing WBC. High hyperdiploid patients were younger and tended to have C/pre-B ALL. Triploidy/tetraploidy (3%) decreased and pseudodiploidy (11%) increased with increasing WBC. Cytogenetic classification was prognostically important (chi-square for heterogeneity of classification = 53.56; P < 0.0001) and added significance to age, sex and WBC. A poor prognosis for patients classed as t(9;22) (13% disease-free survival at 3 years), as t(4;11) 24% at 3 years) and hypodiploid (11% at 3 years), and good prognosis for abn12p (4% of subjects) and high hyperdiploidy (74% and 59% at 3 years respectively) were statistically significant, but the 54% 3-year disease-free survival for patients with t(1;19) was not. The prognosis of patients classed as t(9;22) was independent of other single variables. Abn12p, abnormalities of 11q (including t(4;11) cases) and hypodiploidy added prognostic significance to all other variables combined.

Increased sensitivity of minimal residual disease detection by interphase FISH in acute lymphoblastic leukemia with hyperdiploidy

Interphase fluorescent in situ hybridization (FISH) for the detection of minimal residual disease detection (MRD) in patients with acute lymphoblastic leukemia (ALL) and a high hyperdiploid clone (>50 chromosomes) at diagnosis is presented. By simultaneous targetting of three chromosomes gained, a sensitivity of 10(4) was achieved. Control values (mean + s.d. x 2 of false positive cells in normal peripheral blood) using probes singly, in pairs or as a triplet were 1.4-2.0%, 0.01-0.02% and zero (in 10(4) cells), respectively. A serial dilution experiment mixing control blood lymphocytes with bone marrow from a patient with a >85% cells with >50 chromosomes and probing it with single, dual or triple probes, revealed the clone down to dilutions of 10(-1), 10(-3) and 10(-4), respectively. FISH confirmed chromosomal gains at diagnosis (13 cases) and in relapse (three cases). Positive remission samples (0.01 to 0.06% cells with chromosome gains) were more frequent during the first 7 months (7/12) from diagnosis than later (3/11). Serial studies showed a decline in clone size with time. Conversion from a negative to a positive sample heralded relapse in one case. FISH confirmed an isolated central nervous system relapse and detected a hyperdiploid clone in a chromosomally normal relapse. This technique could be applied whenever three cytogenetic/genetic changes are found.

Relapse of acute promyelocytic leukemia follows serial negative RT-PCR assays: a cautionary tale

Six patients with acute promyelocytic leukaemia (APL) and t(15;17) were investigated by cytogenetics and by reverse transcriptase polymerase chain reaction (RT-PCR) for the fusion transcript PML-RARA. The clone was detected in remission following all-trans retinoic acid and chemotherapy by cytogenetics and/or by RT-PCR up to 2 months from diagnosis. Thereafter the PML-RARA transcript was not seen in 20/21 first remission samples in five cases studied. Remission was maintained in two patients, one following bone marrow transplantation (BMT). Despite serial negative RT-PCR results, PML-RARA reemerged at or prior to relapse following BMT in the remaining three cases. Frequent molecular monitoring and caution in the interpretation of negative RT-PCR results are indicated in APL.

Isochromosomes in acute lymphoblastic leukaemia: i(21q) is a significant finding

The incidence, type, and clonality of isochromosomes at diagnosis were investigated in acute lymphoblastic leukaemia (ALL). An isochromosome was detected in 50/1,035 (4.8%) of successfully karyotyped patients, 41/919 children (4.5%) and 9/116 adults (7.8%), who were diagnosed within a 5 year period. Isochromosomes of 21q with breakpoints in the short arm at p11 or in the long arm at q10 or q22 were identified in 15 patients (1.4%) associated with B-lineage immunophenotype, a white blood cell count (WBC) of < 10 x 10(9)/litre, and pseudo- or low hyperdiploidy. Isochromosomes of 17q and 7q occurred in 13 (1.3%) and 9 (0.9%) patients, respectively, and were associated with high hyperdiploidy. Isochromosomes of 9q and 6p occurred in 6 (0.6%) and 5 (0.5%) patients, respectively, whereas i(Xp), i(lq), and i(8q) occurred in I patient each. The isochromosome occurred as the sole abnormality in 4 patients [3 with i(21q) and I with i(7q)] and in the stemline, but with other chromosomal changes, in 35 patients. It was confined to a clonally evolved sideline in II patients. Isochromosomes occurred with established abnormalities in 7 patients: with t(1;19)-i(7q)/i(9q)/i(7q) and i(9q) each in I patient; with t(4;11)-i(7q)/i(17q) in 1 and 2 patients, respectively; and with t(9;22)-i(9q) in I patient. This study indicates that isochromosome formation can be an early chromosomal change and suggests that i(21q) occurs more frequently at diagnosis than has been previously suspected.

Probes for hidden hyperdiploidy in acute lymphoblastic leukaemia

The detection of hyperdiploidy (clones with >46 chromosomes) in the bone marrow of patients with acute lymphoblastic leukaemia (ALL) is important because of the prognostic impact of this finding. The high hyperdiploid (HeH) subgroup with 51-68 chromosomes is associated with the best outcome, followed by the low hyperdiploid (HeL) subgroup with 47-50 chromosomes and the triploid/tetraploid (TT) subgroup with >68 chromosomes, which do less well. We present a strategy for the use of fluorescence in situ hybridization (FISH) with chromosome-specific probes to detect hyperdiploidy in interphase cells and to assign cases to a ploidy subgroup. By using a model population of 252 cases, it was seen that ten chromosomes (X, 4, 6, 8, 10, 14, 16, 18, 20, and 21) used in particular combinations and applied in a step-wise manner enabled the detection of 94% of hyperdiploid cases and gave an accurate prediction of ploidy subgroup in 96% of these cases. The detection and classification of each case required the use of four to six probes over two or three steps. Confirmation that this strategy will achieve this level of detection in other hyperdiploid populations was demonstrated by using 250 published karyotypes. This strategy has an application in detecting missing or hidden hyperdiploid cases among cases with failed or normal cytogenetics.

Single-cell trisomy in hematologic malignancy. Random change or tip of the iceberg?

Finding a clone in the bone marrow of a patient with a hematologic disorder is important to confirm the neoplastic nature of the disease and may be indicative of prognosis. Since cytogenetic analysis detects only actively dividing clones, the presence of a single abnormal cell among 20 cells analyzed raises doubts about its clonal nature. Fluorescence in situ hybridization (FISH) enables rapid detection of certain chromosomal abnormalities in metaphase and interphase cells, thus enabling detection of minor or inactive clones. Seven patients with hematologic malignancy each having random cell(s) were investigated thus: at diagnosis, with MDS and a cell with +8 (two cases) or +9 (one case) and with AML and a cell with +4 (one case), +7 (one case), or two cells with +9, +22/ +10, +17, +17 (one case). One patient with ALL in remission had one cell with trisomy 4. One patient, a male aged 66 years with refractory anemia with ringed sideroblasts, was found to have a minor trisomy 8 clone in his diagnostic marrow. A follow-up marrow 42 months later showed no trisomy 8 cell among 62 metaphases analyzed, and the percentage of trisomic cells using FISH on interphase cells was within the control range. This patient has survived for more than 42 months requiring no treatment. Single-cell abnormalities in the other six cases proved to be random events. Thus it appears that single-cell abnormalities may not be clonal or at most indicate the presence of a minor clone well below the level of cytogenetic detection. The prognostic significance of such minor clones is at present unclear.

Constitutional and acquired trisomy 8

Trisomy 8 is seen in a range of disorders both constitutional and acquired. The full constitutional condition presents with physical stigmata, skeletal abnormalities and a mild to moderately retarded IQ. Trisomy 8 is frequently seen as a mosaic in the blood or in the skin or both. Trisomy 8 as an acquired condition is found in haematological disorders, notably in myelodysplasia (MDS) and acute myeloid leukaemia (AML), and is restricted to the malignant cells. These arise in the bone marrow and may also be found in the peripheral blood. Reported in the issue (Zollino et al. (1995) Leukemia Res. 19(10), 733) is a case of a patient with constitutional trisomy 8 mosaicism who developed myelodysplasia with trisomy 8 in 95-100% of bone marrow cells. Here we consider the implications of this case to the diagnosis of both malignant and constitutional conditions.

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

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, 6 Ph+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(1;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 microns). 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 microns) 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(1;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.

Detection of the BCR-ABL gene by reverse transcription/polymerase chain reaction and fluorescence in situ hybridization in a patient with Philadelphia chromosome negative acute lymphoblastic leukaemia

The Philadelphia (Ph) chromosome is detected in leukaemia cells in approximately 20% of adults with acute lymphoblastic leukaemia (ALL). When treated with chemotherapy alone, Ph-positive ALL has a poor prognosis, and patients may benefit from bone marrow transplantation in first remission. Here we report a patient with chromosomally normal bone marrow, in all 60 cells analysed, who was found to have the p210-type BCR-ABL chimaeric transcript by RT/PCR. Fluorescence in situ hybridization was labelled cosmid probes for BCR and ABL showed the presence of BCR-ABL juxtaposition on a normal chromosome 22 in leukaemia cell metaphases. We conclude that molecular and cytogenetic methods should be used in conjunction to detect the BCR-ABL gene rearrangement in ALL.

Expression of the E2A-PBX1 fusion transcripts in t(1;19)(q23;p13) and der(19)t(1;19) at diagnosis and in remission of acute lymphoblastic leukemia with different B lineage immunophenotypes

The chromosomal translocation t(1;19)(q23;p13) and its variant form der(19)t(1;19) found in 3-5% of acute lymphoblastic leukemia (ALL) results in the expression of the E2A-PBX1 fusion transcript. Although strongly associated with a pre-B immunophenotype, we report the occurrence of t(1;19) in bone marrow or peripheral blood in nine patients with ALL with the following immunophenotypes: pre-B ALL (four), c-ALL (two), c-ALL clg not tested (one), null-ALL (one) and mature B-ALL (one). The E2A-PBX1 fusion transcript investigated by reverse-transcriptase polymerase chain reaction (RT-PCR) was seen in all patients at diagnosis and/or on follow-up samples. Six patients are alive in first clinical remission. Of these patients, three were PCR+ve from between 2 and 38 months from diagnosis, and three were PCR-ve when examined at 5, 26 and 51 months from diagnosis. Two patients are in second remission. One was PCR+ve at 18 months, suffered a CNS relapse at 21 months but was PCR-ve 1 month later. The other was PCR+ve in remission at 2 and 11 months from diagnosis and in testicular relapse at 31 months, but was PCR-ve 5 months later. The remaining patient died 2 months from diagnosis and was not investigated in remission. The prognostic significance of these findings remains to be investigated.

Detection of BCR-ABL and E2A-PBX1 fusion genes by RT-PCR in acute lymphoblastic leukaemia with failed or normal cytogenetics

To evaluate the use of molecular analysis as a complement to karyotypic analysis in the detection of specific chromosomal abnormalities, the occurrence of t(1;19)(q23;p13) and t(9;22)(q34;q11) was investigated by RT-PCR in 43 diagnostic acute lymphoblastic leukaemia cases in whom cytogenetic investigations had failed (32 cases) or showed only a normal karyotype (> or = 20 normal metaphases, 11 cases). One child (aged 14 years) and five adults (aged 18-60 years) were BCR-ABL positive on first round for M-BCR-ABL (one case) or m-BCR-ABL (one case), or on nested PCR for m-BCR-ABL (three cases). Co-expression of M-BCR-ABL (first-round PCR) and m-BCR-ABL (nested PCR was seen in one case. One m-BCR-ABL-positive case also expressed the E2A-PBX1 fusion transcript. Patients positive for the transcript(s) were older, had higher white blood cell counts and a significantly poorer event-free survival (P < 0.001) than those negative for the transcript.

Association of 17p loss with late-stage or refractory disease in hematologic malignancy

Twenty-five patients with loss of part or all of 17p were selected from 701 patients with hematologic malignancies karyotyped either at diagnosis and/or at relapse and/or in refractory disease. Loss of 17p resulted from partial arm deletion (eight cases), unbalanced translocation (12 cases), i(17)(q10)(five cases) or monosomy 17 (four cases). In three cases, both 17ps were missing; in one case, two sublines independently acquired loss of 17p. In eight cases, loss of 17p was confirmed as a secondary change. The karyotypes generally were complex, with an average of 4.0 structurally abnormal chromosomes in the simplest lines showing 17p loss. The incidence at diagnosis was acute lymphoblastic leukemia (ALL) 2.2%, acute myeloid leukemia (AML) 2.4%, and myelodysplastic syndrome (MDS) 3.4%. The incidence in relapse and refractory disease was ALL 8.9%, AML 3.3%, and MDS 6.3%. The increased incidence of 17p loss in relapse and refractory disease was statistically significant (p < 0.05). Loss of 17p appears to be a feature of late-stage or resistant disease in hematologic malignancy.

E2A/HLF fusion cDNAs and the use of RT-PCR for the detection of minimal residual disease in t(17;19)(q22;p13) acute lymphoblastic leukemia

Three cases of acute lymphoblastic leukemia (ALL) with the rare t(17;19)(q22;p13) translocation were investigated for E2A/HLF fusion genes using reverse transcription coupled with polymerase chain reaction (RT-PCR). The patients had C-ALL, F/17 years (case 1) or pre-B ALL, M/11 years (case 2) and M/13 years (case 3). Case 1 had an event-free survival (EFS) of 42 months. Case 2 was ultimately refractory to treatment. Case 3 presented following EFS of 16 months in morphological remission (1% blasts), but with immunological and cytogenetic evidence of active disease, then relapsed, remitted and relapsed. Type II E2A/HLF fusion cDNA was found at diagnosis (cases 1, 2), at presentation (case 3) and in all samples tested, whether with active disease or in complete remission (CR). Case 3 showed, in addition, type I fusion E2A/HLF cDNA at presentation, through induction therapy when there was evidence of active disease, but not in CR. Cases 1 and 3 had bone marrow transplantation while in CR but with residual disease detectable by RT-PCR. All patients have died of ALL. Two cases (2 and 3) had hypercalcemia with bone lesions. No case had any evidence of disseminated intravascular coagulation. This is the first demonstration of the value of RT-PCR for the detection of minimal residual disease in t(17;19) ALL.

Two types of genomic rearrangements create alternative E2A-HLF fusion proteins in t(17;19)-ALL

The t(17;19)(q21-q22;p13.3) in acute lymphoblastic leukemia results in creation of an E2A-HLF fusion protein with structural and functional properties of a chimeric transcription factor. Two types of genomic rearrangements underlie fusion of E2A with HLF. In type I rearrangements, an insertion that codes for a portion of the chimera not found in either wild type protein occurs between E2A exon 13- and HLF exon 4-encoded sequences. This insertion is derived from a cryptic exon created at the junction between chromosomes 17 and 19, and includes intronic portions of both E2A and HLF with intervening nontemplated N nucleotides. Type II rearrangements arise from more 5' breakpoints in E2A and result in fusion cDNAs with E2A exon 12 spliced directly to HLF exon 4. Analysis of the genomic structure of HLF shows that these different modes of protein fusion result from selective constraints to maintain the proper HLF reading frame, because a direct E2A exon 13 to HLF exon 4 splice would lead to translation of a truncated E2A protein lacking any contribution from HLF. These features underscore the requirement for DNA binding and/or dimerization conferred by the bZIP portion of the E2A-HLF chimera in t(17;19)-ALL.

Two Down syndrome patients with an acquired translocation, t(8;14)(q11;q32), in early B-lineage acute lymphoblastic leukemia

Two males with Down syndrome and acute lymphoblastic leukemia with the acquired translocation, t(8;14)(q11;q32), are described. In each case the constitutional karyotype was 47,XY,+21. The patients were, respectively, aged 3 years 11 months and 32 years, with presenting white blood counts 34 and 1.9 x 10(9)/L with blasts of FAB L1 and L2. In each case immunophenotype of the blasts was C-ALL. The child is alive and well and in first remission 6 years from diagnosis. In contrast, the adult patient died in first remission 8.5 months from diagnosis with severe pancytopenia. These are to our knowledge the second and third cases of ALL with t(8;14)(q11-12;q32) associated with a constitutional genetic disorder.

Evolution of complex chromosomal rearrangements in a case of biphenotypic pre-B/myeloid acute leukemia

A case of acute biphenotypic leukemia, in which blast cells coexpress antigens of both lymphoid and myeloid lineages, was seen in a 24-year-old female. The clonal karyotype was complex but did not include any of the abnormalities previously found in biphenotypic leukemia. Chromosome abnormalities included breakpoints seen in both acute lymphoblastic and acute myeloid leukemias as well as a number of known fragile sites, namely the rare heritable fragile site at 10q24, and the common, aphidicolin-induced sites on chromosome 7.

DCC tumor suppressor gene is inactivated in hematologic malignancies showing monosomy 18

DCC (deleted in colorectal cancer) is a candidate tumor suppressor gene recently identified on chromosome band 18q21. Loss of one DCC allele or decreased DCC expression occurs in more than 70% of colorectal cancers, suggesting that DCC inactivation constitutes a critical event in the development of these tumors. Using polymerase chain reaction amplification of cDNA, we have studied DCC expression in bone marrow from 4 patients with leukemia (1 chronic myeloid leukemia-blastic crisis, case 1; 1 acute myeloid leukemia, case 2; 1 T-cell acute lymphoblastic leukemia [ALL], case 3; 1 B-cell ALL, case 4) showing loss of one DCC allele due to monosomy 18. We also studied DCC expression in multiple control samples, including normal lymphocytes, normal tonsillar tissue, and leukemias without 18q abnormalities. Four primer pairs consistently amplified the predicted DCC sequences from cDNA prepared from all control samples. However, in samples with monosomy 18, DCC transcripts were either not detected (case 1) or detected at a very low level (cases 2, 3, and 4). Southern analysis showed no structural rearrangement of the remaining DCC locus in all leukemia samples. Thus, loss of DCC expression was demonstrated in association with loss of one DCC allele in all cases tested. These results suggest that, as for colorectal tumors, the inactivation of DCC can have a role in the development of hematologic malignancies.

Interphase in situ hybridization reveals minimal residual disease in early remission and return of the diagnostic clone in karyotypically normal relapse of acute lymphoblastic leukemia

Early clinical remission of acute lymphoblastic leukemia (ALL) was examined by fluorescence in situ hybridization (FISH) in bone marrow cells from eight patients with high hyperdiploid (> 50 chromosomes) clones at diagnosis. Alphoid centromeric probes to chromosomes X, 10, 17, and 18, trisomic at diagnosis, were used as appropriate. Three hematologically normal marrows were used as controls. At diagnosis, trisomic interphase cells ranged from 69.3-84.4%. One month later, trisomic and tetrasomic interphase cells were significantly increased over control frequencies in 2/7 cases tested (p < 0.05 and p < 0.001) and trisomy alone in one case (p < 0.05). At two months post-diagnosis, trisomy and tetrasomy were in the control range. Pentasomy and hexasomy, not seen in controls, were found in 5/7 samples at one month and in 1/5 samples at two months. One patient examined in chromosomally normal relapse had 34.4% trisomic cells by FISH at confirmed relapse (p < 0.001). An additional hyperdiploid case, examined at central nervous system relapse, had increased numbers of trisomic cells (p < 0.01) in a morphologically and cytogenetically normal marrow. These findings demonstrate the elimination of aberrant ploidy in most hyperdiploid cases two months from diagnosis and indicate that failure to detect the abnormal clone in relapse may result from selective mitotic activity of chromosomally normal cells, rather than relapse in a cytogenetically normal clone.

Prognostic implications of breakpoint and lineage heterogeneity in Philadelphia-positive acute lymphoblastic leukemia: a review

Philadelphia-positive (Ph) acute lymphoblastic leukemia (ALL) is heterogeneous both in terms of the BCR gene breakpoints (M-bcr and m-bcr) and in the number of cell lineages carrying the Ph chromosome. The impact of these observations on the controversy surrounding Ph ALL and Ph+ chronic granulocytic leukemia (CGL) is unclear. Twenty cases of Ph ALL (four newly investigated and 16 previously published) were classified into nine stem-cell (the Ph in myeloid and lymphoid cells) and 11 lymphoid-restricted cases. Lymphoid cases had a lower leucocyte count (56 x 10(9)/l) than stem-cell cases (151 x 10(9)/l) (p < 0.01). The M-bcr and m-bcr breakpoints (in 14 cases) were found in lymphoid (four cases of each) and stem-cell (five and one cases respectively) cases. Lymphoid cases had significantly shorter event-free survival (median 4 months) than stem-cell cases (median 35 months) (p < 0.01). M-bcr cases were older (mean 41 years) than m-bcr cases (mean 36 years)(p = NS); m-bcr cases had higher leukocyte counts (mean 85 x 10(9)/l) than M-bcr cases (36 x 10(9)/l)(p < 0.01) but breakpoint had no impact on prognosis. Lineage involvement, but not breakpoint, appears to distinguish prognostically important sub-groups of Ph ALL. Paradoxically, lymphoid-restricted cases have a worse prognosis than cases arising in a pluripotent stem-cell.

Testicular relapse in Philadelphia chromosome positive acute lymphoblastic leukaemia

A case of Philadelphia-positive (Ph) acute lymphoblastic leukaemia (ALL) in a 40-year-old male is presented. At diagnosis, 80% of bone marrow cells were Ph. Remission with normal blood counts was achieved but the marrow became hypercellular, indicating conversion to chronic granulocytic leukaemia (GCL). The Ph clone persisted with a variable percentage of Ph cells. He developed testicular relapse 38 months from diagnosis. The patient died when engraftment with a matched unrelated bone marrow transplant failed. Molecular investigation of DNA prepared from diagnostic and remission bone marrow and from testicular tissue in relapse revealed the same sized rearranged fragment of the BCR gene using a probe to the major breakpoint cluster region. This case confirms that testicular involvement due to infiltration of the testes by the original Ph leukaemic clone may occur as an unusual complication in Ph ALL. Conversion to chronic-phase GCL, a rare occurrence in Ph ALL, may have contributed to the unusually long survival.

Isochromosome 1q in acute monocytic leukemia: a new nonrandom association

We report a case of de novo acute monocytic leukemia in a 25-year-old man in whom the sole clonal cytogenetic abnormality was an additional isochromosome 1q. Cytogenetic polymorphisms indicate that, in addition to the formation of the isochromosome, a duplication of the remaining normal chromosome 1 had taken place. Other reported cases suggest an association between acute monocytic leukemia and i(1q).

Prognostic significance of the balanced t(1;19) and unbalanced der(19)t(1;19) translocations in acute lymphoblastic leukemia

The recurring chromosomal 1;19 translocation in acute lymphoblastic leukemia (ALL) occurs in balanced t(1;19) (q23;p13) and unbalanced, -19, +der(19)t(1;19)(q23;p13) forms. The clinical features and outcome were compared for 30 patients with the t(1;19) and 36 patients with the der(19) forms. These were 45 children (less than 1-14 years) and 21 adults (15-54 years) (median age 9.0 years), 41 females, 25 males, with median white blood count (WBC) 20.9 x 10(9)/1. Patients were classified by karyotype thus: t(1;19) 11 cases; t(1;19) with additional change (+A) 19 cases; der(19) 17 cases; and der(19) +A, 19 cases. Non-random additional structural abnormalities included involvement of 1q, 6q, i(7q), i(9q), 9p, and 13q. The only significant difference in clinical or blast cell features between patients with the t(1;19) and the der(19) was the greater age of adults with t(1;19) (p less than 0.05). Projected median event-free survival and survival of all cases together was 22 months and greater than 112 months respectively. Neither age nor WBC contributed significantly to prognosis. For patients at all ages, prognosis of der(19) was better than t(1;19). This was statistically significant for event-free and overall survival in childhood (p = 0.02 and p = 0.01 respectively) and was independent of age (p = 0.04 and p = 0.008 respectively) and WBC (p = 0.03 and p = 0.04 respectively). Future studies should examine separately the outcome for patients with the balanced and unbalanced forms of the t(1;19).

Karyotype and T-cell receptor expression in T-lineage acute lymphoblastic leukemia

The relationship between karyotype and expression of the T-cell receptor (TCR) proteins was examined in 19 patients with T-lineage acute lymphoblastic leukemia (T-ALL). All patients expressed CD3 molecules in the cytoplasm or on the cell membrane. Patients were classified according to TCR expression thus: no TCR expression (TCR-), six cases; cytoplasmic expression of TCR beta chain (cTCRB) only, six cases; membrane expression of TCR alpha and beta chains (mTCRAB), five cases; membrane expression of TCR gamma and delta (mTCRGD), two cases. A chromosomally abnormal clone was detected in 15 cases. The most common site of chromosomal change was at 14q11 (seven cases), the chromosomal band to which TCRA and TCRD have been mapped; as a deletion (two cases); or as a translocation with reciprocal breakpoints in bands containing the TCRG (7p15); TCRB (7q35); or putative oncogenes HOXII (10q24), RBTN2 (11p13) or MYC (8q24) genes. Breakpoints were also seen in 6q (three cases), 9p (two cases), or 11q23 (two cases). The following observations were made: All four chromosomally normal cases lacked TCR expression (TCR-). Breakpoints at 14q11 were found in one of six TCR- cases, four of six cTCRB cases, and two of five mTCRAB cases. Abnormalities of 6q and of 9p were seen only in cases with full TCR expression (mTCRAB or mTCRGD).

Inversion of chromosome 16 with the Philadelphia chromosome in acute myelomonocytic leukemia with eosinophilia. Report of two cases

Two cases are described with the rare combination of inv(16)(p13q22), strongly associated with acute myelomonocytic leukemia with eosinophilia, M4Eo, and the Philadelphia translocation, t(9;22)(q34;q11), hallmark of chronic myeloid leukemia (CML) and rarely found, (less than 1%), in acute nonlymphocytic leukemia. The patients were: case 1, a 9-year-old girl presenting with a white blood cell count (WBC) 42 x 10(9)/L with 32% blasts and bone marrow with blasts and eosinophil precursors consistent with M4Eo, and case 2, a 25-year-old man with WBC 34.7 x 10(9)/L with 13% blasts and bone marrow with features of M4Eo and basophilia. Both patients achieved remission but died following bone marrow transplantation in first remission (case 1) or in relapse (case 2). Cytogenetic findings were: case 1, at diagnosis, 46,XX,inv(16)(p13q22)(21)/46,XX,t(9;22) (q34;q11),inv(16)(8)/46,XX(10), and case 2, at diagnosis, 46,XY,t(9;22) (q34;q11),inv(16)(p13q22) (16) and in remission, 46,XY,t(9;22)(q34;q11) (1)/46,XY (24). Investigation of the breakpoint on 22 in case 1 with Southern blotting and the polymerase chain reaction demonstrated the presence of a p190 mRNA and a breakpoint typical of acute leukemia. Thus a diagnosis of M4Eo was supported by clinical and cytogenetic sequelae in each case; the Ph in case 1 was apparently secondary to inv(16), in case 2 the Ph probably preceded inv(16) in the etiology of the leukemia.

Ewing's sarcoma t(11;22) in a case of acute nonlymphocytic leukemia

Chromosome analysis of bone marrow cells from a patient with acute nonlymphocytic leukemia M2 revealed the translocation t(11;22)(q24;q12) usually associated with Ewing's sarcoma. Molecular investigations ruled out the possibility that this was a variant Philadelphia translocation with breakpoints in the major breakpoint cluster region. Although cytogenetic analysis was not available at diagnosis, this abnormality was found both pre- and postallogeneic bone marrow transplant.

Near haploid acute lymphoblastic leukemia: seven new cases and a review of the literature

Seven new cases are described of near haploid acute lymphoblastic leukemia (ALL) and the findings reviewed together with updated complete remission duration and survival data for the 21 cases already published. The patients were four males and three females, with an age range 2-19 years; all had an immunophenotype consistent with common ALL. The poor prognostic outlook for patients with near haploid ALL is confirmed by the median remission duration of 14 months for these patients, which is comparable to that for the previously published cases. The pattern of chromosome loss was marked particularly by the presence of two copies of chromosomes 10, 14, 18, 21 and both sex chromosomes. Populations of hyperdiploid cells with double the near haploid number were observed in six of the patients, one of whom demonstrated further clonal evolution, and it is proposed that some cases classified as hyperdiploid ALL with greater than 50 chromosomes may also have arisen from a near haploid stem line.

Evaluation of cytogenetic samples and pertinent technical variables in adult acute lymphocytic leukemia

Data on 200 bone marrow and peripheral blood samples received from 190 adults with acute lymphoblastic leukemia (ALL) were analyzed with respect to sample type (bone marrow or peripheral blood), sample cell count (concentration and total count), time in transit (days), and year of analysis. Each sample was assessed for 1) number and quality of metaphases, and 2) presence or absence of a clone. Sample type, concentration of cells, time in transit, and year of analysis all significantly affected the number and quality of metaphases and the detection of a clone. The chance of obtaining 10 or more cells for cytogenetic analysis in adult ALL was shown to be as low as 10% with a suboptimal sample (peripheral blood, low cell concentration) and as high as 70% with an optimal sample (bone marrow, adequate cell concentration, 1 day or less in transit). The likelihood of detecting a clone was smallest (0%) for the group (bone marrow, adequate cell concentration, 2 or more days in transit) and greatest (68%) in the optimal group (bone marrow, adequate cell concentration, 1 day or less in transit).