Translocation (8;21) and its variants in acute nonlymphocytic leukemia. The relative importance of chromosomes 8 and 21 to the genesis of the disease

Acute myeloid leukemia with new complex t(8;21;22) induced hemophagocytic lymphohistiocytosis: A case report

RATIONALE

The balanced translocation t(8;21;22)(q22;q22;q11.2) is not reported previously, although t(8;21)(q22;q22) is seen in approximately 7% of adults and most frequent abnormality in children with newly diagnosed acute myeloid leukemia (AML). AML-associated hemophagocytic lymphohistiocytosis (HLH) is a rare event, reported only of limited numbers. The present study reports a very rare case of t(8;21;22)(q22;q22;q11.2) with AML, not reported previously, and developed HLH at the same time.

PATIENT CONCERNS AND DIAGNOSIS

A 15-year-old girl presented with a history of bleeding gums and high fever, leukocytosis, anemia, and thrombocytopenia. While waiting the result of bone marrow aspirate, the HLH-associated examinations were abnormal. Bone marrow aspirate showed a hypercellular marrow with 1% myeloblasts. The cytogenetic and molecular studies revealed the presence of abnormal karyotype-46, XX, t(8;21;22)(q22;q22;q11.2) and RUNX1-RUNX1T1 fusion gene. Genetic detections of HLH showed heterozygous genetic variants in lysosomal trafficking regulator (LYST). Hence, she was diagnosed with AML with t(8;21;22)(q22;q22;q11.2) and HLH.

INTERVENTIONS AND OUTCOMES

All HLH clinical symptoms disappeared after the 4 weeks treatment of HLH. Then the patient received standard AML induction chemotherapy and the leukemia relapsed after 2 cycles of high-dosed consolidation therapy. Eventually, the patient received emergent paternal haploidentical hematopoietic stem cell transplantation based on the complex variant translocation, leukemia replased state and HLH with compound heterozygotes mutation, and achieved sustained remission with RUNX1-RUNX1T1 negative for more than 1 year.

LESSONS

Patients with some specific recurrent cytogenetic abnormalities should be diagnosed with AML regardless of the blast count, for example t(8;21). We should improve the understanding of complex variant translocations. HLH-related genetic mutations were not only found in primary HLH, but also in second HLH.

Molecular cytogenetic investigations in a novel complex variant of t(8;21)(q22;q22) with ins(15;21)(q15;q22.2q22.3) in a patient with AML-M2 subtype

Acute myeloid leukemia (AML) is a clinically and molecularly heterogeneous disease characterized by the aberrant proliferation of myeloid stem cells, reduced apoptosis and blockage in cellular differentiation. The present report describes the results of hematological, cytogenetic, and fluorescence in situ hybridization (FISH) analysis in a 25-year-old man diagnosed with AML-M2. Cytogenetic as well as FISH analysis revealed a complex translocation involving four chromosomes, with the karyotype 45,-Y,der(X)t(X;8)(p21;q22),der(8)t(8;21)(q22;q22),ins(15;21)(q15;q22.2q22.3),der(21)t(8;21)(q22;q22). The breakpoints at 8q22 and 21q22 suggested a rearrangement of the RUNX1T1 (alias ETO) and RUNX1 (previously AML1) genes, respectively. Using a dual-color FISH test with RUNX1T1 and RUNX1 probes, we demonstrated an RUNX1/RUNX1T1 fusion signal on the derivative chromosome 8, establishing this translocation as a novel complex variant of t(8;21)(q22;q22).

Abnormalities of the long arm of chromosome 21 in 107 patients with hematopoietic disorders: a collaborative retrospective study of the Groupe Français de Cytogénétique Hématologique

Chromosome 21 is frequently rearranged in hematopoietic malignancies. In order to detect new chromosomal aberrations, the Groupe Français de Cytogénétique Hématologique collected a series of 107 patients with various hematologic disorders and acquired structural abnormalities of the long arm of chromosome 21. The abnormalities were subclassified into 10 groups, according to the location of the 21q breakpoint and the type of abnormality. Band 21q22 was implicated in 72 patients (excluding duplications, triplications, and amplifications). The involvement of the RUNX1 gene was confirmed in 10 novel translocations, but the gene partners were not identified. Eleven novel translocations rearranging band 21q22 with bands 1q25, 2p21, 2q37, 3p21, 3p23, 4q31, 6p24 approximately p25, 6p12, 7p15, 16p11, and 18q21 were detected. Rearrangements of band 21q11 and 21q21 were detected in six novel translocations with 5p15, 6p21, 15q21, 16p13, and 20q11 and with 1p33, 3q27, 5p14, 11q11, and 14q11, respectively. Duplications, triplications, amplifications, and isodicentric chromosomes were detected in eight, three, eight, and three patients, respectively. The present study shows both the wide distribution of the breakpoints on the long arm of chromosome 21 in hematopoietic malignancy and the diversity of the chromosomal rearrangements and the hematologic disorders involved. The findings invite further investigation of the 21q abnormalities to detect their associated molecular rearrangements.

A variant t(8;10;21) in a patient with pathological features mimicking atypical chronic myeloid leukemia

We report the case of an 11-year-old girl who was initially diagnosed with a chronic myeloproliferative disorder, possibly chronic myelogenous leukemia (CML), based on laboratory and blood and marrow morphological findings. The patient's high leukocyte count did not respond to hydroxyurea, a standard initial therapy for CML. Chromosomal analysis revealed that the patient did not have t(9;22), but a complex t(8;10;21)(q22;q24;q22), a variant of t(8;21). The treatment regime was switched to an acute myeloid leukemia (AML) protocol; the patient responded well and is now in remission. This case demonstrates again that routine clinical cytogenetic analysis plays an important role in the clinical diagnosis, guidance of treatment, and prognostication in hematological disorders.

AML1 interconnected pathways of leukemogenesis

The AML1 transcription factor, identified by the cloning of the translocation t(8;21) breakpoint, is one of the most frequent targets for chromosomal translocations in leukemia. Furthermore, polysomies and point mutations can also alter AML1 function. AML1, also called CBF alpha 2, PEBP alpha 2 or RUNX1, is thus implicated in a great number of acute leukemias via a variety of pathogenic mechanisms and seems to act either as an oncogene or a tumor suppressor gene. Characterization of AML1 knockout mice has shown that AML1 is necessary for normal development of all hematopoietic lineages and alterations in the overal functional level of AML1 can have a profound effect on hematopoiesis. Numerous studies have shown that AML1 plays a vital role in the regulation of expression of many genes involved in hematopoietic cell development, and the impairment of AML1 function disregulates the pathways leading to cellular proliferation and differentiation. However, heterozygous AML1 mutations alone may not be sufficient for the development of leukemia. A cumulative process of mutagenesis involving additional genetic events in functionally related molecules, may be necessary for the development of leukemia and may determine the leukemic phenotype. We review the known AML1 target genes, AML1 interacting proteins, AML1 gene alterations and their effects on AML1 function, and mutations in AML1-related genes associated with leukemia. We discuss the interconnections between all these genes in cell signaling pathways and their importance for future therapeutic developments.

21q22 balanced chromosome aberrations in therapy-related hematopoietic disorders: report from an international workshop

The International Workshop on the relationship between prior therapy and balanced chromosome aberrations in therapy-related myelodysplastic syndromes (t-MDS) and therapy-related acute leukemia (t-AL) identified 79 of 511 (15.5%) patients with balanced 21q22 translocations. Patients were treated for their primary disease, including solid tumors (56%), hematologic malignancy (43%), and juvenile rheumatoid arthritis (single case), by radiation therapy (5 patients), chemotherapy (36 patients), or combined-modality therapy (38 patients). 21q translocations involved common partner chromosomes in 81% of cases: t(8;21) (n = 44; 56%), t(3;21) (n = 16; 20%), and t(16;21) (n = 4; 5%). Translocations involving 15 other partner chromosomes were also documented with involvement of AML1(CBFA2/RUNX1), identifying a total of 23 different 21q22/AML1 translocations. The data analysis was carried out on the basis of five subsets of 21q22 cases, that is, t(8;21) with and without additional aberrations, t(3;21), t(16;21), and other 21q22 translocations. Dysplastic features were present in all 21q22 cases. Therapy-related acute myeloid leukemia (t-AML) at presentation was highest in t(8;21) (82%) and lowest in t(3;21) (37.5%) patients. Cumulative drug dose exposure scores for alkylating agents (AAs) and topoisomerase II inhibitors indicated that t(3;21) patients received the most intensive therapy among the five 21q22 subsets, and the median AA score for patients with secondary chromosome 7 aberrations was double the AA score for the entire 21q22 group. All five patients who received only radiation therapy had t(8;21) t-AML. The median latency and overall survival (OS) for 21q22 patients were 39 and 14 months (mo), compared to 26 and 8 mo for 11q23 patients, 22 and 28 mo for inv(16), 69 and 7 mo for Rare recurring aberrations, and 59 and 7 mo for Unique (nonrecurring) balanced aberration (latency P < or = 0.016 for all pairwise comparisons; OS, P < or = 0.018 for all pairwise comparisons). The percentages of 21q22 patients surviving 1 year, 2 years, and 5 years were 58%, 33%, and 18%, respectively. Noticeable differences were observed in median OS between 21q22 patients (n = 7) receiving transplant (BMT) (31 mo) compared to 21q22 patients who received intensive non-BMT therapy (n = 46) (17 mo); however, this was nonsignificant because of the small sample size (log-rank, P = 0.33). t-MDS/t-AML with balanced 21q22 aberrations was associated with prior exposure to radiation, epipodophyllotoxins, and anthracyclines, dysplastic morphologic features, multiple partner chromosomes, and longer latency periods when compared to 11q23 and inv(16) t-MDS/AML Workshop subgroups. In general, patients could be divided into two prognostic risk groups, those with t(8;21) (median OS, 19 mo) and those without t(8;21) (median OS, 7 mo) leukemia (log-rank, P = 0.0007).

Comparison of cytogenetic and molecular genetic detection of t(8;21) and inv(16) in a prospective series of adults with de novo acute myeloid leukemia: a Cancer and Leukemia Group B Study

PURPOSE

To prospectively compare cytogenetics and reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of t(8;21)(q22;q22) and inv(16)(p13q22)/t(16;16)(p13;q22), aberrations characteristic of core-binding factor (CBF) acute myeloid leukemia (AML), in 284 adults newly diagnosed with primary AML.

PATIENTS AND METHODS

Cytogenetic analyses were performed at local laboratories, with results reviewed centrally. RT-PCR for AML1/ETO and CBFbeta/MYH11 was performed centrally.

RESULTS

CBF AML was ultimately identified in 48 patients: 21 had t(8;21) or its variant and AML1/ETO, and 27 had inv(16)/t(16;16), CBFbeta/MYH11, or both. Initial cytogenetic and RT-PCR analyses correctly classified 95.7% and 96.1% of patients, respectively (P =.83). Initial cytogenetic results were considered to be false-negative in three AML1/ETO-positive patients with unique variants of t(8;21), and in three CBFbeta/MYH11-positive patients with, respectively, an isolated +22; del(16)(q22),+22; and a normal karyotype. The latter three patients were later confirmed to have inv(16)/t(16;16) cytogenetically. Only one of 124 patients reported initially as cytogenetically normal was ultimately RT-PCR-positive. There was no false-positive cytogenetic result. Initial RT-PCR was falsely negative in two patients with inv(16) and falsely positive for AML1/ETO in two and for CBFbeta/MYH11 in another two patients. Two patients with del(16)(q22) were found to be CBFbeta/MYH11-negative. M4Eo marrow morphology was a good predictor of the presence of inv(16)/t(16;16).

CONCLUSION

Patients with t(8;21) or inv(16) can be successfully identified in prospective multi-institutional clinical trials. Both cytogenetics and RT-PCR detect most such patients, although each method has limitations. RT-PCR is required when the cytogenetic study fails; it is also required to determine whether patients with suspected variants of t(8;21), del(16)(q22), or +22 represent CBF AML. RT-PCR should not replace cytogenetics and should not be used as the only diagnostic test for detection of CBF AML because of the possibility of obtaining false-positive or false-negative results.

Two cases of AML (M2) with a t(8;19)(q22;q13): a new cytogenetic variant

"Simple" variants of the t(8;21) translocation involving chromosome 8 and a chromosome other than number 21 are rare. To our knowledge, only t(3;8)(q29;q22), t(8;11)(q22;q13), t(8;16)(q22;q24), t(8;20)(q22;p13), and t(8;22) have been reported in the literature. This paper describes for the first time two patients with acute myelogenous leukemia with a consistent t(8;19)(q22;q13) translocation. Their myelograms were compatible with the FAB-M2 subtype. The blasts from case 2 expressed CD34, CD33, CD13, and CD19. Karyotype analyses were performed on bone marrow cells using R- and G-banding at presentation. A t(8;19)(q22;q13) translocation was found in 28/30 metaphases for case 1 and in 23/25 metaphases for case 2. The latter case also had a deletion of chromosome 9, del(9)(q12q22) as an additional abnormality. Reverse transcriptase-polymerase chain reaction study revealed no AML1/ETO fusion transcript in case 2. Dual-color fluorescence in situ hybridization (FISH) assay using two probes (BAC92 and YAC412A4) convincingly demonstrated that the chromosomal material from 8q was translocated onto 19q rather than 19p in case 2. Thus, we consider t(8;19)(q22;q13) a true "simple" variant of t(8;21), and assume that a fusion gene resulting from the t(8;19) may contain the ETO gene located at 8q22 and an unknown partner gene from 19q13, which probably is a new transcription factor, whose molecular entity warrants further study.

Myeloid differentiation antigen and cytokine receptor expression on acute myelocytic leukaemia cells with t(16;21)(p11;q22): frequent expression of CD56 and interleukin-2 receptor alpha chain

We report the cellular characteristics of cells from three patients with de novo acute myelocytic leukaemia (AML) with t(16;21)(p11;q22), two M4 and one M5a according to the FAB classification, and two permanent cell lines with t(16;21)(p11;q22), TSU1621MT and YNH-1. The FUS/ERG fusion mRNA was demonstrated in all cases by reverse transcriptase-polymerase chain reaction (RT-PCR). The immunophenotypes of the AML cells, and YNH-1 and TSU1621MT cell lines with t(16;21) were characterized as CD34+CD33+CD13+CD11b+CD18+CD56+ HLA-DR-/+. Cells from all samples strongly expressed c-kit, granulocyte colony-stimulating factor receptor (G-CSFR), c-fms (macrophage colony-stimulating factor receptor), interleukin-3 receptor alpha chain (IL-3Ralpha), and granulocyte macrophage colony-stimulating factor receptor alpha chain (GM-CSFRalpha), and these data corresponded well to the growth responsiveness to the cytokines. IL-2Ralpha expression was also found in all t(16;21) samples, but IL-2 did not act on the proliferation of the leukaemic cells in in vitro cultures. G-CSF distinctly promoted the proliferation of leukaemic cells of t(16;21) AML, but did not enhance the expression of MPO and neutrophil differentiation of these cells. Our findings indicate that AML cells with t(16;21) preserve stem cell properties such as CD34 and c-kit expression, and suggest that they have the potential to differentiate into a monocytic lineage. The relationship between the unique cellular characteristics (especially CD56 and IL-2Ralpha expression) and FUS/ERG protein remains undetermined.

Simple variant t(8;21) acute myeloid leukemias harbor insertions of the AML1 or ETO genes

We report on the molecular characterization of two acute myeloid leukemias (AML), one AML-M1 (patient 1) and one AML-M2 (patient 2) with t(8;21)(p21;q22) and t(8;20)(q22;p13), respectively, at diagnosis. The locations of the breakpoints, 21q22 in patient 1 and 8q22 in patient 2, prompted us to search for a cryptic t(8;21)(q22;q22) and involvement of the AML1 and ETO genes. Dual-color fluorescence in situ hybridization (FISH) using whole chromosome painting probes for chromosomes 8, 20, and 21 confirmed the conventional cytogenetic karyotypes. However, dual-color FISH using appropriate ETO and AML1 probes disclosed an insertion of AML1 into 8q22 on the derivative chromosome 8 in patient 1 and of ETO into 21q22 on one chromosome 21 in patient 2, leading to AML1-ETO fusion signals. Both cases expressed an AML1-ETO transcript, shown by reverse transcriptase polymerase chain reaction and cDNA sequencing. Creation of functional AML1-ETO fusion genes in these two simple variant t(8;21) probably occurred through complex mechanisms, combining translocation and insertion of chromosomal segments.

New variant translocation (8;20)(q22;q13) in acute myelocytic leukemia

A new variant translocation, (8;20)(q22;q13) in a patient with acute myelocytic leukemia (AML) M2 is reported. As far as we know, this is the second case of the t(8;20) in de novo AML. Further studies are required to clarify the key event leading to the development of AML-M2.

Cytogenetic survey of 53 Moroccan patients with acute myeloblastic leukemia

We present a cytogenetic survey of chromosome aberrations for 53 Moroccan patients with acute myeloblastic leukemia (AML). Our 53 patients were 2 to 70 years old with 31 men and 22 women. The cytogenetic study was performed with the following three methods: first, relative proportion of normal (N) or abnormal (A) metaphases; second, presence of specific or random abnormalities; and third, karyotype complexity. Among 36 patients (67%) with a chromosomal abnormality, 18 (34%) showed a specific aberration. We have found t(9;22) in three patients (5%), chromosome 5 or 7 abnormality in six (11%), del(11)(q23) in three (6%), +21 in four (8%), and +8 in two (4%). Specific translocations associated with FAB type were found: t(8;21) with AML2 in 12 patients (23%) and t(9;11) with AML5 in one (2%). Rare abnormalities were also found: one patient with t(7;21) associated with AML2 and another patient with r(1) ring associated with AML1. We concluded that our study in a Moroccan population confirmed the relation between some specific abnormalities and the FAB classification. We have found a higher incidence for t(8;21) than usually described. Finally, we have identified chromosomal abnormalities t(7;21)(q22;p11) and r(1), rarely described before.

Establishment and characterization of IRTA17 and IRTA21, two novel acute non-lymphocytic leukaemia cell lines with t(16;21) translocation

The t(16;21)(p11;q22) translocation is an infrequent chromosomal abnormality, but seems specific to acute non-lymphocytic leukaemia (ANLL). We established two cell lines with t(16;21)(p11;q22) from the bone marrow of a patient with ANL in relapse. Their morphological, karyotypic, immunohistochemical and genetic features are examined. Although both cell lines show monocytoid features morphologically, they express only CD13 (My7) and CD34, and neither expressed monocytoid or lymphoid markers. Reverse transcription-polymerase chain reaction showed that both cell lines expressed a similar TLS-ERG chimaeric mRNA as a result of the t(16;21)(p11;q22) translocation. As far as we know, there is no report of a leukaemia cell line with t(16;21). These cell lines represent a useful tool for leukaemia research.

Variant t(8;21) rearrangements in acute myeloblastic leukemia of childhood

In a collaborative cytogenetic analysis of blast cells from 638 children with acute myeloid leukemia, 74 (11.6%) of the patients had the typical t(8;21)(q22;q22), while seven (1.1%) had complex variant translocations also involving 8q22 and 21q22 as well as a variable chromosome. In each case with a complex rearrangement, the myeloid leukemic cells contained Auer rods and were classified as M2 in the French-American-British (FAB) system. These seven children had a median age of 14 years (range, 7.3-18.9 years), a median initial leukocyte count of 9.1 x 10(9)/L (range, 2.5-142.2 x 10(9)/L), and have survived leukemia free for a median of 23 months (1-41 months) after attaining complete remission. The variable chromosomes in these seven cases--1, 2, 7, 12, 13, 15, and 17--appeared to be randomly involved. The clinico-biologic features of our cases with a variant t(8;21) are consistent with those of the published cases with the standard t(8;21), and support the hypothesis that the critical genetic alteration produced by the t(8;21) is located on the derivative 8.

Translocation (16;21)(p11;q22) in acute nonlymphocytic leukemia

A case of acute nonlymphocytic leukemia (ANLL) with a translocation (16;21)(p11;q22) is presented. Clinical features of ANLL with this chromosomal change are discussed.

An ets-related gene, ERG, is rearranged in human myeloid leukemia with t(16;21) chromosomal translocation

The t(16;21)(p11;q22) translocation is a nonrandom chromosomal abnormality found in several types of myeloid leukemia, which show variable cytomorphological features. We constructed rodent-human somatic cell hybrids containing the der(16) chromosome from leukemic cells of a patient with t(16;21). Using these hybrids, we mapped the translocation breakpoint on the Not I restriction map of chromosome 21 which we had previously constructed. The result showed the proximity of the breakpoint to the ERG gene, a member of the ets oncogene superfamily. Polymerase chain reaction and Southern blot analyses of genomic DNA from the hybrids and from peripheral blood cells and bone marrow cells of patients with t(16;21) showed that the breakpoints were clustered within a single intron in the coding region of the ERG gene. This finding and the results obtained by Northern blot analysis suggested the formation of a chimeric product(s) by fusion of the ERG gene and an unknown counterpart gene on chromosome 16.

Acute non-lymphocytic leukemia with t(16;21)

A patient with ANLL FAB subtype M1 was found to possess a t(16;21)(p11;q22) and trisomy 10. The 16;21 translocation has been reported in 12 other cases of ANLL, of various subtypes, and its relationship to the disease profile is discussed.

DNA sequences of chromosome 21-specific YAC detect the t(8;21) breakpoint of acute myelogenous leukemia

The t(8;21)(q22;q22) is a nonrandom translocation specifically marking blasts of acute myelogenous leukemia (AML) with undifferentiated phenotype. The breakpoint on chromosome 21 involved by this rearrangement has been precisely localized relative to cloned DNA markers by physical and genetic linkage analysis enabling the use of positional cloning for its isolation. Yeast artificial chromosome (YAC) clones for loci proximal (D21S65) and distal (ERG) to the (21q22) breakpoint have been developed and their chromosome 21 origin and location relative to the breakpoint has been established. By using in situ hybridization analysis, a 240 kb YAC clone for the D21S65 locus clearly identified both derivative chromosomes of the (8;21) translocation in metaphase spreads of leukemia blasts with the rearrangement. The characterization of the DNA sequences contained in this 240 kb YAC can reveal the functional consequences of their derangement in leukemia with abnormalities of the (21q22) region.

Chromosome abnormalities and prognosis in childhood acute leukemia

We report here on the leukemic cell karyotypes of 134 children with acute nonlymphocytic leukemia (ANLL) examined at Saitama Children's Medical Center (SCMC), and of 88 children with acute lymphoblastic leukemia (ALL) referred to SCMC. The patients were mainly treated according to the protocol of the Tokyo Children's Cancer Study Group. Of 106 ANLL cases with adequate banding, 18% were normal, 34% had miscellaneous clonal abnormalities, and 48% were classified into known cytogenetic subgroups: t(8;21) (n = 21), 11q23 abnormalities (n = 14), -7/del(7q) (n = 6), inv (16)/del(16) (n = 5), and t(15;17) (n = 5). According to the FAB classification, M7 (21.7%) were more frequent than in previous reports because this study included a number of Down's Syndrome patients with M7 morphology. The present study confirmed the well-known association of t(15;17) with M3, t(8;21) with M2, 11q23 abnormalities with M4 and M5, and inv (16)/del(16) with M4. Patients with t(8;21) or inv (16)/del(16q) ANLL fared no better overall than the entire group. Of 51 ALL cases with adequate banding, 13.7% were normal, and 86.3% were classified into abnormal subgroups: translocation (n = 14), hyperdiploidy (greater than 50) (n = 13), and miscellaneous abnormalities (n = 17). Cases with hyperdiploidy (greater than 50) were restricted to a common phenotype and fared better overall than the entire group. Patients with translocation were found in all phenotypes, and had a poor prognosis. We concluded that childhood acute leukemia could be subgrouped according to karyotypic patterns, and that patients with translocations had a poor prognosis in ALL as well as ANLL.

Translocation (16;21)(p11;q22) in acute monoblastic leukemia with erythrophagocytosis

A patient with acute monoblastic leukemia with erythrophagocytosis and a t(16;21) (p11;q22), poor response to chemotherapy, early relapse, and a short survival of ten months is presented. Hematologically, this patient could be considered as a case of FAB M5b/t(8;16) but without the characteristic chromosomal translocation, i.e., there is no visible alteration on chromosome 8 and the breakpoint on chromosome 16 appears to be very proximal. These findings are briefly discussed in the light of other variants.

t(16;21)(p11.2;q22): a recurrent primary rearrangement in ANLL

We have identified three patients with acute nonlymphocytic leukemia (ANLL), subtypes M2, M4, and M7, who had a t(16;21)(p11.2;q22) in the affected cells. There are six previously reported cases of ANLL with the same t(16;21). The t(6;21) should therefore be included as another primary rearrangement in ANLL. Follow-up of these cases, though still limited, suggests a poor prognosis, as most patients have achieved a clinical remission but only for a short duration.

Cytogenetics of three cases of ANLL M2 and M4. Involvement of chromosomal region 8q22 in all three but 21q22 in only one

Cytogenetic investigation of the bone marrow of two patients with acute nonlymphocytic leukemia (ANLL), French-American-British Cooperative group (FAB) classification M2, revealed a translocation (8;22)(q22.1;q13.3), without involving chromosome 21, and a variant translocation (8;21)(q22;q22). These findings, together with a del(8)(q22) found in a patient with refractory anemia, erythroblastic (RAEB)-t with progression to acute myelogenous leukemia (AML)-M4, are discussed in relation to the possible role of abnormalities of chromosomes 8 and 21 in the oncogenesis of ANLL M2 and M4.

Radiation exposure and chromosome abnormalities. Human cytogenetic studies at the National Institute of Radiological Sciences, Japan, 1963-1988

The results of human cytogenetic studies performed at the National Institute of Radiological Sciences (NIRS), Chiba, Japan for about 25 years are described. The studies were pursued primarily under two major projects: one involving people exposed to radiation under various conditions and the other involving patients with malignant diseases, especially leukemias. Whereas chromosome abnormalities in radiation-exposed people are excellent indicators of radiation exposure, their behavior in bone marrow provide useful information for a better understanding of chromosome abnormalities in leukemias and related disorders. The role of chromosome abnormalities in the genesis and development of leukemia and related disorders is considered, suggesting a view for future studies in this field.

Novel translocations in acute nonlymphocytic leukemia. Two cases involving chromosome 21, band q22

We present two cases in which translocations involving 21q22 were found at presentation in acute nonlymphocytic leukemia (ANLL). The first of these translocations, t(3;21)(q26-q27;q22), is previously unknown in ANLL, but appears indistinguishable from that reportedly associated with Philadelphia-positive chronic myelogenous leukemia. The second case involves t(15;21)(q21-q22;q22), a translocation previously undescribed in ANLL. Both of these exchanges involve 21q22 plus another chromosome region associated with leukemogenesis. We attempted to interrelate these cytogenetic data with the oncogenic significance of 21q22.

Cytogenetics of childhood acute nonlymphocytic leukemia

Interest in more precise subclassification of the acute leukemias by cytogenetic criteria led us to identify and characterize the full range of chromosomal abnormalities in 121 children with de novo acute nonlymphocytic leukemia (ANLL). Only 21% of the cases had normal karyotypes; 62% had consistent or recurrent alterations, most commonly inv(16) or del(16), t(8;21), t(15;17), t(9;11), t(11;V) or del(11), and -7 or 7q-; and 17% had miscellaneous, apparently random, clonal abnormalities. Statistically significant associations between chromosomal abnormalities and the morphologic/cytochemical subtypes of ANLL, defined by criteria of the French-American-British (FAB) cooperative group were demonstrated for the t(8;21) in M1 and M2 leukemia, t(15;17) in M3, t(9;11) in M5, and translocations involving 11q23 other than t(9;11) [t(11;V)] or del(11q) in M4 and M5. The chromosome 16 inversion was not restricted to the M4 subtype, as is generally reported, and was not uniformly associated with increased and/or abnormal marrow eosinophils. None of these 121 cases were characterized by the Philadelphia chromosome, nor did any have the t(6;9), t(16;16), or inv(3), which have been noted previously in this disease. In addition to confirming several recognized correlations between recurrent structural chromosome abnormalities and FAB subtypes, this study identified novel abnormalities that have not been reported by others. It also disclosed an unusual heterogeneity of chromosome 16 abnormalities with respect to their distribution among FAB subtypes, their association with marrow eosinophilia, and their participation with other chromosomes in translocations.

Acute nonlymphocytic leukemia following lung cancer in a patient with a constitutional supernumerary chromosome

A patient with a constitutional bisatellited supernumerary marker chromosome developed a large cell lung carcinoma and subsequent acute nonlymphocytic leukemia (ANLL) of the M2 type showing an (8;21) translocation and del(9). The ANLL-M2 appeared to be independent of the lung carcinoma. The presence of the supernumerary chromosome might have been associated with the development of the two diseases.