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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.

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.

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.

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.

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).

The role of fluorodeoxyuridine (FUdR) synchronization in cytogenetic analysis of acute lymphoblastic leukemia (ALL) was investigated using samples of bone marrow (BM) (10 patients) and peripheral blood (PB) (2 patients), prepared for chromosome analysis using both 24-hour unstimulated cultures (24-hr) and cultures synchronized with FUdR. The mitotic index (MI) in FUdR was lower than in 24-hr in 8 of 10 BM and 2 of 2 PB cultures. The quality of the metaphases was the same in both cultures. The FUdR had a lower percentage of abnormal cells than the 24-hr in the 7 BM samples with a normal/abnormal population and sufficient analyzable cells in each culture for comparison (p less than 0.05). PB FUdR cultures yielded only normal cells. We conclude that FUdR cultures are inferior to 24-hr cultures for chromosome analysis in ALL.

At least 25 structural chromosomal abnormalities are now found in acute lymphoblastic leukemia (ALL). Many of the abnormalities are associated with particular clinical or blast cell features. Chromosomal translocation breakpoints in ALL are among those that define regions of the genome of oncogenic potential, the recognition of which has led to an improved understanding of the mechanisms of leukemogenesis. The prognostic importance of chromosome findings in ALL concerns demonstration of long-term survival in patients with high hyperdiploid leukemic clones and identification of patients with certain translocations who are at high risk of treatment failure and for whom alternative therapy such as bone marrow transplantation may be desirable. This review summarizes the more recent chromosomal findings in childhood and adult ALL and discusses how increasing recognition of structural change and adoption of alternative therapy for high-risk chromosomal groups may change the prognostic role of cytogenetics in this type of leukemia.

Karyotypes of 21 patients, originally entered into the Third International Workshop on Chromosomes in Leukemia (3IWCL), were investigated in first, second and/or subsequent relapses. Karyotypes at diagnosis were related to the relapses in the following ways: normal to normal (N-N) (five cases); abnormal to normal (A-N) (two cases); abnormal to abnormal with no change (A-A) (five cases); abnormal to abnormal with clonal evolution (A-A+) (eight cases); and normal to abnormal (N-A) (one case). The A-A group comprised two each of t(4;11) and t(9;22) cases and one pseudodiploid case; included in this group were the only two patients who did not receive intensive treatment. Both A-N cases had been pseudodiploid at diagnosis. Clonal evolution A-A+ occurred in patients who had had 47-49 chromosomes or pseudodiploidy at diagnosis and was mainly due to the addition of structural change. The additional abnormalities were different in each case. The only de novo appearance of a clone (N-A) was in host cells in relapse following bone marrow transplantation. Clonal evolution occurred in patients who had been intensively treated and who relapsed late; the median time from diagnosis to relapse studied for the A-A group was 6 months and for the A-A+ group was 24 months. Survival following relapse was shorter for patients who had had a clonal abnormality at any time (median 10 months) than for those with no abnormality at diagnosis or in relapse (median 26 months).

The clinical importance of chromosome studies of leukemic tissue at diagnosis of acute lymphoblastic leukemia lies in the relationship between different chromosomal findings and prognoses. First demonstrated in 1978 [1], this relationship has been confirmed in a number of subsequent reports [2-9]. The independence of chromosomal findings from other prognostic features in predicting long-term response to treatment is now established [2-5, 7-9]. In children, a good or bad prognosis can be predicted only when a chromosomally abnormal cell line is identified. Differential prognosis, then, depends on the nature of the abnormality. In adults, as in children, the kind of abnormal clone, when present, is of some value prognostically. In addition, however, unlike the situation in children, the best prognosis in adults is associated with the chromosomally normal group.

Bone marrow and peripheral blood from 121 children with acute lymphoblastic leukemia spent 3 hours in transit before being cultured. Cultures were harvested directly, after 24, 48, or 72 hours, and following methotrexate synchronization. Details of techniques are given. Analyzable mitoses were obtained in 78 cases. Failures contained no detectable clone and fewer than five mitoses (27 cases) or fewer than five analyzable mitoses (16 cases). A clone was found in 44 cases. In some cases the clone was found in two or more cultures, conversely a clone in the direct harvest was not always found after overnight culture and vice versa. Hyperdiploid clones were always found in the bone marrow and frequently in two or more cultures. Pseudodiploid clones found in the blood in four cases evaded detection in the bone marrow. The use of methotrexate did not yield prometaphase chromosomes or improve the yield of analyzable cells. The number of cultures employed influenced the yield of metaphases and appeared to influence clone detection. More cultures were needed to detect a pseudodiploid clone than to detect a hyperdiploid clone. Detection of a clone may be maximized by using the following combination of cultures: bone marrow direct and overnight, and peripheral blood overnight.

The standard t(9;22)(q34;q11) found in Philadelphia (Ph) chromosome positive chronic myeloid leukemia (CML) involves a highly restricted (5.8 kb) chromosome 22 breakpoint cluster region (bcr), which results in the formation of a chimeric gene comprising exons from the 5' end of bcr and protooncogene c-abl coding sequences from chromosome 9. In a survey of 21 patients with hematologic and clinical features of CML we detected rearrangement of the chromosome 22 bcr by gene probe analysis in all cases, including 16 with a standard t(9;22), two with variant Ph translocations [t(10;22)(q26;q11);t(11;22)(p15;q11)], one with a complex Ph translocation [t(9;11;22)(q34;q13;q11)], one with a complex translocation and a masked Ph[t(9;14;22) (q34;q24;q11)], and one Ph-negative case with a t(1;9)(p32;q34). These observations further substantiate the suggestion that, despite karyotypic heterogeneity, a common underlying molecular lesion, the bcr-abl gene chimera, is involved in the disease pathogenesis of CML.

To evaluate the importance of pretreatment karyotype in predicting long-term outcome in acute lymphoblastic leukemia (ALL), we performed a follow-up study of the 329 patients from the Third International Workshop on Chromosomes in Leukemia. Living patients have now been followed a minimum of 6 years. Patients were divided into ten groups according to pretreatment karyotype: no abnormalities, one of the following structural abnormalities [the Philadelphia chromosome, rearrangements involving 8q24, t(4;11), 14q+, 6q-] or, in the remaining cases, modal number (less than 46, 46, 47-50, greater than 50). As previously reported for achievement and duration of complete remission, and overall survival, disease-free survival differed significantly (p less than 0.001) among chromosome groups for both adults and children. Among children, karyotype was an independent prognostic factor for predicting disease-free survival. Because of the long follow-up, we now have been able to utilize statistical models to estimate the percentage of patients cured, according to karyotype alone and combined with other risk factors. Adults with the highest likelihood of cure (21-33%) were those patients with FAB-L1, a leukocyte count of 50,000/microliters or less, and one of the following chromosome groups: greater than 50, 47-50, 6q-, or normal. In children these same characteristics were associated with the highest percentage of cure (58-71% cured). In addition, we identified several groups of children with less than 15% chance of cure who clearly need to be treated as high-risk patients at diagnosis. Future studies of patients who have received risk-adapted therapy based on these chromosome data are needed to determine if more intensive treatment will improve the outlook of patients with cytogenetically unfavorable types of ALL.