Cytogenetic findings in chronic myeloid leukemia (CML); evaluation of karyotype, blast morphology, and survival in the acute phase

Cytogenetic and molecular genetic evolution of chronic myeloid leukemia

Chronic myeloid leukemia (CML) is genetically characterized by the presence of the reciprocal translocation t(9;22)(q34;q11), resulting in a BCR/ABL gene fusion on the derivative chromosome 22 called the Philadelphia (Ph) chromosome. In 2-10% of the cases, this chimeric gene is generated by variant rearrangements, involving 9q34, 22q11, and one or several other genomic regions. All chromosomes have been described as participating in these variants, but there is a marked breakpoint clustering to chromosome bands 1p36, 3p21, 5q13, 6p21, 9q22, 11q13, 12p13, 17p13, 17q21, 17q25, 19q13, 21q22, 22q12, and 22q13. Despite their genetically complex nature, available data indicate that variant rearrangements do not confer any specific phenotypic or prognostic impact as compared to CML with a standard Ph chromosome. In most instances, the t(9;22), or a variant thereof, is the sole chromosomal anomaly during the chronic phase (CP) of the disease, whereas additional genetic changes are demonstrable in 60-80% of cases in blast crisis (BC). The secondary chromosomal aberrations are clearly nonrandom, with the most common chromosomal abnormalities being +8 (34% of cases with additional changes), +Ph (30%), i(17q) (20%), +19 (13%), -Y (8% of males), +21 (7%), +17 (5%), and monosomy 7 (5%). We suggest that all these aberrations, occurring in >5% of CML with secondary changes, should be denoted major route abnormalities. Chromosome segments often involved in structural rearrangements include 1q, 3q21, 3q26, 7p, 9p, 11q23, 12p13, 13q11-14, 17p11, 17q10, 21q22, and 22q10. No clear-cut differences as regards type and prevalence of additional aberrations seem to exist between CML with standard t(9;22) and CML with variants, except for slightly lower frequencies of the most common changes in the latter group. The temporal order of the secondary changes varies, but the preferred pathway appears to start with i(17q), followed by +8 and +Ph, and then +19. Molecular genetic abnormalities preceding, or occurring during, BC include overexpression of the BCR/ABL transcript, upregulation of the EVI1 gene, increased telomerase activity, and mutations of the tumor suppressor genes RB1, TP53, and CDKN2A. The cytogenetic evolution patterns vary significantly in relation to treatment given during CP. For example, +8 is more common after busulfan than hydroxyurea therapy, and the secondary changes seen after interferon-alpha treatment or bone marrow transplantation are often unusual, seemingly random, and occasionally transient. Apart from the strong phenotypic impact of addition of acute myeloid leukemia/myelodysplasia-associated translocations and inversions, such as inv(3)(q21q26), t(3;21)(q26;q22), and t(15;17)(q22;q12-21), in CML BC, only a few significant differences between myeloid and lymphoid BC are discerned, with i(17q) and TP53 mutations being more common in myeloid BC and monosomy 7, hypodiploidy, and CDKN2A deletions being more frequent in lymphoid BC. The prognostic significance of the secondary genetic changes is not uniform, although abnormalities involving chromosome 17, e.g., i(17q), have repeatedly been shown to be ominous. However, the clinical impact of additional cytogenetic and molecular genetic aberrations is most likely modified by the treatment modalities used.

Philadelphia-positive chronic myelogenous leukemia with a 5q-- abnormality in a patient following interferon-alpha therapy

In this report, we describe a rare 5q--/CML association in a patient with Ph-positive chronic myelogenous leukemia (CML) who achieved complete cytogenetic response on interferon-alpha (IFN-alpha) treatment, but who developed a new clone in the blastic crisis. The patient was treated with interferon-alpha beginning in 1996 and a serial chromosome and molecular study was performed over the clinical course of the disease. The patient remained in complete hematologic and cytogenetic remission until November 1998, when a reverse transcriptase PCR study performed on the bone marrow and peripheral blood cells was negative for chimeric BCR/ABL mRNA. The treatment was discontinued until April 1999, when the patient developed acute transformation of the disease. In June 1999, cytogenetic examination showed the development of a new clone, consisting of the deletion of the long arm of chromosome 5 in addition to the standard Ph translocation. The unusual association of a Ph with an abnormality usually observed in a secondary myeloproliferative disease raises the question of whether the new finding is treatment-induced or part of the disease process and casually related to the acute transformation.

Two different Philadelphia chromosomes in a cell line from an AML-M0 patient

A second Philadelphia (Ph) chromosome is one of the most common nonrandom secondary chromosome changes in leukemias with 9;22 translocations. It has been suggested, and observed in two studies of masked t(9;22), that the second Ph chromosome is an exact duplication of the entire derivative chromosome 22. In a cytogenetic study of bone marrow cells from an acute myelogenous leukemia patient, a cell line carrying two different Ph chromosomes evidenced by a chromosome 22 centromeric heteromorphism was found. From this observation arose the question whether the second der(22) was a true Ph chromosome or whether it was a deleted chromosome derived from the normal chromosome 22 that did not contain the bcr-abl rearrangement. A fluorescent in situ hybridization (FISH) study with the t(9;22) probe revealed two bcr-abl positive signals on 60 of 100 interphase nuclei. The second Ph could have resulted from a mitotic crossing over; or, analogously to late-appearing Philadelphia chromosomes, it may be derived from a new chromatid translocation between the chromosomes 9 and 22 not involved in the initial t(9;22).

Cytogenetics of chronic myelogenous leukaemia

The Philadelphia (Ph) chromosome is present in the leukaemic cells of most patients with chronic myelogenous leukaemia. Variant translocations occur in 10% of patients but breakpoints on chromosomes 9 and 22 remain the same, so prognosis of these patients is unchanged. Clonal evolution is infrequent in chronic phase and its significance depends on the specific chromosome involved, the number of metaphases affected and the timing in the chronic phase. The majority of patients in blastic phase demonstrate clonal evolution; three specific abnormalities (+Ph, +8 and isochromosome 17q) are present in 70% of patients. Loss of the Ph chromosome on therapy is associated with prolonged survival. For monitoring these events conventional G-band cytogenetics (CG) is essential at presentation to characterize the Disease cytogenetically, while fluorescence in situ hybridization (FISH) on hypermetaphase preparations (hypermetaphase FISH (HMF)) is important for establishing the specific frequency of Ph+ cells. During treatment FISH on interphase cells (I-FISH) can monitor the level of Ph+ cells in circulation, while CG may be used to identify any suspected clonal evolution. Where I-FISH is negative, HMF is essential to evaluate minimal residual disease.

Isochromosome 17q as a sole anomaly: a distinct myelodysplastic syndrome entity?

We report four patients with myelodysplastic syndrome (MDS) with isochromosome i(17q) as the sole chromosomal anomaly. One patient was classified as refractory anemia (RA) and three as refractory anemia with excess of blasts (RAEB). All four patients shared several features such as male sex, advanced age, severe anemia, as well as a bone marrow with myeloproliferative characteristics: hypercellularity, prominent baso- and eosinophilia, and marked increase of micromegakaryocytes. We suggest that patients with i(17q) as the sole chromosomal anomaly may identify a distinct MDS with characteristics between MDS and chronic myeloproliferative disorders (CMPD).

Blastic phase chronic myeloid leukemia with a four-break rearrangement: t(11;9)(9;22)(q23;p22q34;q11)

Chromosome analysis of bone marrow (BM) aspirate from a 36-year-old man with chronic myeloid leukemia (CML) in blastic phase (BP) showed a four-break rearrangement t(11;9)(9;22)(q23; p22q34;q11), which can be considered a t(9;22)(q34;q11) and a secondary t(9;11)(p22;q23). It is not surprising that additional chromosome abnormalities occur in patients with Ph-positive CML in BP, but it is of interest that t(9;11)(p22;q23), characteristic of acute myeloid leukemia French-American-British (FAB) type M5 (ANLL-M5) was observed. The possible meaning of this additional change in BP of CML is discussed.

Deletion (7)(p11p15) in a patient with Philadelphia-positive chronic myelogenous leukemia

We report a case of chronic myelogenous leukemia (CML) with a Philadelphia (Ph) chromosome. During the transformation phase of the disease, a del(7)(p11p15) and a +Ph were identified as additional chromosomal anomalies. We believe that loss of the segment 7p11-->p15 may play an important role in the progression of the disease.

A study of prognostic factors in blast crisis of Philadelphia chromosome-positive chronic myelogenous leukaemia

In 80 patients with Ph-positive chronic myelogenous leukaemia the main clinical, haematological and cytogenetical data were recorded at diagnosis of blast crisis and evaluated for prognostic significance. At the time of the analysis 73 patients had died, with a median survival of 4-8 months from diagnosis of blast crisis for the whole series. When analysed as a time-dependent variable, the achievement of a favourable response to chemotherapy resulted in a longer patient's survival. On the other hand, the univariate analysis identified six pretreatment characteristics associated with a poorer prognosis: a longer chronic phase, presence of extramedullary blastic involvement, a platelet count below 200 x 10(9)/l, a less marked leucocytosis, a blood blast cell percentage higher than 10%, and presence of trisomy 8. The latter parameters were included in a multiple regression model together with the blast cell phenotype (lymphoid versus non-lymphoid), and only four of them (trisomy 8, duration of chronic phase, platelet count, and leucocyte count) retained their prognostic influence. When the therapeutical response was also included in the regression model, it proved to be the most important prognostic variable, followed by trisomy 8, length of chronic phase, extramedullary disease, and platelet count, whereas the leukocyte count lost its predictive value. Thus, in spite of the short overall survival of blast crisis patients, the identification of prognostic factors in such a haematological condition may be of interest, especially in the interpretation of new therapeutical approaches.

Cytogenetic peculiarities in chronic myelogenous leukemia

Cytogenetic investigations were performed in 185 patients with chronic myelogenous leukemia (CML) at all stages of the disease; 166 patients were Ph positive-159 (95.8%) of these showing the standard Ph translocation, and 7 (4.2%) variant translocations-17 patients were Ph negative. In 2 patients the cytogenetic analysis was unsuccessful. Additional aberrations were found in 40 (24.1%) of the Ph-positive patients. Nine (52.9%) of the Ph-negative patients showed chromosome anomalies. Besides the well known nonrandom abnormalities (-7, +8, i(17q), +19, +Ph) we found a high frequency of clones with rare or not yet described structural rearrangements--in 14 cases (34.2%) of the Ph-positive patients and in 2 cases (20%) of the Ph-negative patients with other chromosome abnormalities. The clinical significance of these findings is discussed.

Cytogenetic findings and biologic behavior of giant cell tumors of bone

Giant cell tumor of bone is a benign but often aggressive lesion with a distinct tendency toward local recurrence and, rarely, malignant transformation. Over a 3-year period, 20 giant cell tumors from 14 different patients were cytogenetically characterized. Random chromosomal abnormalities were detected in 14 of the 20 specimens and clonal chromosomal abnormalities were detected in six. An unusual anomaly, telomeric fusion, was the most striking random chromosomal abnormality detected. A comparison of the presence or absence of cytogenetic aberrations and the clinical behavior of these neoplasms was studied as well as a comparison of the aberrations in the initial specimen with those in subsequent specimens. Chromosomal abnormalities were detected in all but one of the ten tumors shown to be locally aggressive, recurrent, or metastatic. (The abnormalities observed in five of these tumors were clonal). There were no chromosomal abnormalities present in three of four tumors that behaved in an innocent fashion. These findings support the presence of chromosomal abnormalities in giant cell tumors (telomeric fusion in particular) and suggest that cytogenetic analysis may be useful in predicting the biologic behavior of these neoplasms.

Characterization of deletions of chromosome 7 short arm occurring as primary karyotypic anomaly in acute myeloid leukaemia

Three patients with an acute myeloid leukaemia (AML) showed a deletion of the short arm of chromosome 7 with loss of the deleted material. The 7p- anomaly originated from either a terminal or an interstitial deletion and it represented the only karyotypic aberration in all the three cases. According to the clinical, morphological and immunological features of this series of patients, a 7p- chromosome appears to be associated with a group of AML with myelodysplastic features in the bone marrow, including secondary disorders in patients treated for a previous malignancy.

Initial and subsequent cytogenetic studies in malignant lymphoma

Two or more cytogenetic studies of lymph node biopsy specimens from 12 patients with non-Hodgkin's malignant lymphoma were performed. Each of the 12 patients had at least one clonal structural chromosome abnormality in their initial biopsy specimen. A comparison of the chromosome abnormalities in the initial lymph node biopsy specimens with those in subsequent biopsy specimens was made. Structural and numerical chromosome changes were not always accompanied by a change in the histologic type of the lymphoma. Similarly, a change in histologic type was not always associated with the appearance of new structural or numerical abnormalities. Serial cytogenetic studies from additional patients will further our understanding relevant to which chromosome changes are associated with lymphomagenesis and which are secondary or more of an evolutionary nature.

Sequential karyotype study on Ph-positive chronic myelocytic leukemia. Significance of additional chromosomal abnormalities during disease evolution

Twenty-eight patients with Ph-positive chronic myelocytic leukemia (CML), who all died of the disease, had cytogenetic studies throughout the progression of the disease: at diagnosis, during chronic phase (CP), accelerated phase (AP), and blastic transformation (BT). The aim of this sequential study was to appreciate the frequency and the significance of additional chromosomal abnormalities (ACA) during CML evolution, especially in the CP. In our series ACA were rare (five of 28 patients) and simple (four of five) in CP. They were much more frequent and complex in AP (11 of 16) and in BT (22 of 24) with complex abnormalities (13 of 24). In CP, ACA predictive value for metamorphosis was poor: only three of 13 patients had ACA within 1 year before BT, and only two of 11 within 1 year before AP. ACA were mainly observed during the last period before BT: ten of 17 patients studied within 6 months prior BT had ACA, but by then two of three were in AP. ACA, especially when complex, appear to be a hallmark of CML metamorphosis.

The karyotype of blastic crisis

The nonrandomness of chromosome clonal evolution in blastic crisis of chronic myeloid leukemia is well established, with three major changes [+8, +Ph, i(17q)] occurring alone or in combination in over 70% of the patients. The chromosome changes observed in different tissues may reveal the origin of the abnormal clones, as well as provide evidence for distinct or common evolution by different cell populations. The significance of the chromosome abnormalities and their relationship to blastic conversion are discussed. In general, chromosome evolution may be considered a rather reliable predictive or diagnostic parameter of blastic crisis but both the nature and the subsequent behavior of abnormal clones appear to be of critical value. As to the clinical/chromosome correlations, a few major points have emerged: the i(17q) aberration is mostly associated with signs of myeloid differentiation of blasts and a marked basophilia; it is mainly observed in the late stage of the disease, but overall median survival of patients with this marker is usually long; more atypical or complex changes usually are associated with a worse prognosis; patients with only a Ph in their blasts may have a longer survival, at least in some cytologic subgroups; and d) the loss of the Y chromosome seems to protect the cell against further clonal evolution. Finally, the relevance of the chromosome changes in the multistage process of blastic conversion is discussed, and the breakpoints of secondary changes recorded so far are reviewed and examined. It appears that certain chromosome regions are more often affected; these might contain genes of critical importance for the final malignant progression. Molecular biology may provide insight, in the future, on the nature and expression of involved genes.

Correlation between acquired pseudo-Pelger-Huet anomaly and involvement of chromosome 17 in chronic myeloid leukemia

Acquired pseudo-Pelger-Huet neutrophils appeared in the peripheral blood of 11 of 83 Philadelphia-positive chronic myeloid leukemia patients during the blastic phase of the disease. Chromosomal analysis performed at the time of pseudo-Pelger appearance showed karyotype evolution with involvement of the short arms of a chromosome #17. In eight cases an i(17q) was present, in two cases an unbalanced translocation, and in one case monosomy. All these rearrangements had in common the loss of the distal end of the short arm. The morphologic and chromosomal study of the remaining 72 chronic myeloid leukemia patients demonstrated neither pseudo-Pelger nor 17p involvement.

Frequency of constitutional chromosome alterations in patients with hematologic neoplasias

From 1978 to 1985 cytogenetic studies were performed on 718 patients with different hematologic diseases. Nine (1.25%) had a constitutional chromosome alteration. One patient had trisomy 21, four had balanced translocations and four had sex chromosome anomalies. Although the frequency of constitutional alterations was twice that seen in the newborn population, an analysis of these data and also from the literature shows a random association between constitutional chromosome alterations and hematologic neoplasias, except for patients with Down's syndrome.

Acute promyelocytic transformation of chronic myeloid leukaemia with an isochromosome 17q

Transformation to an acute promyelocytic leukaemia occurred in a patient approximately 2 years after having been diagnosed as suffering from chronic myeloid leukaemia (CML). At this time, in addition to the Ph1 chromosomal aberration, an isochromosome 17q [i(17q)] was noted. The t(15:17) was absent. The implications of this are discussed.

Cytogenetic studies in blast crisis of Ph-positive chronic granulocytic leukemia: results and prognostic evaluation in 52 patients

Bone marrow cytogenetic (G-banding) studies were carried out in 52 patients with Ph-positive chronic granulocytic leukemia (CGL) at the time of diagnosis of blast crisis. In all cases, the Ph chromosome was due to the standard (9;22) translocation. Eighteen patients displayed the 46,Ph cell line unchanged, whereas additional chromosome abnormalities were observed in the remaining 34 patients (65.4%). Among the latter, numerical karyotypic changes were found in 31 patients and structural changes in 8 patients. Five patients displayed numerical and structural changes simultaneously. The most common chromosome numerical changes were an extra #8 (14 cases) and additional Ph chromosomes (11 patients); an i(17q) was the most frequently observed structural change (3 cases). These three aberrations were often combined; at least one of them was present in 21 patients, constituting 62% of the cases with new cytogenetic abnormalities at blast crisis. When comparing the clinical and hematologic characteristics, as well as the survival, of patients retaining the unchanged 46,Ph cell line and patients showing additional chromosome changes, no differences were found between the two groups of patients. However, a minority displaying a hypodiploid modal chromosome number survived significantly longer than the remaining patients.

Significance of secondary cytogenetic changes in patients with Ph-positive chronic granulocytic leukemia in the acute phase

The karyotypic abnormalities in 29 patients in the acute phase of Ph-positive chronic granulocytic leukemia are described. Of 18 Giemsa banded samples, 11 showed one or more of the typical additional abnormalities found in the acute phase, namely +Ph, +8, or i(17q). Survival data from these patients was combined with three published series providing 135 patients and the effect of one, two, or three of these abnormalities tested. The prognosis was significantly worse in patients with two or more additional abnormalities, compared with those with one or none. Analysis of the subset of patients with only one additional abnormality [+Ph or +8 or i(17q)] suggested a worse prognosis in those with +8 than in those with +Ph or i(17q), although the differences were not significant. There also was a trend for patients in whom all metaphases showed abnormalities in addition to the Ph chromosome to have a worse prognosis than those in whom some or all metaphases contained the Ph only. However, this trend just failed to reach a 5% level of significance.

Philadelphia chromosome-positive chronic myelocytic leukemia with a supplementary t(4;9)(q21;p22) and long survival

A Ph-positive chronic myelocytic leukemia (CML) patient was clinically and cytogenetically evaluated during a 12-year period. She acquired a supplementary chromosome abnormality, t(4;9)(q21;p22), at least 5 years prior to transformation to blastic phase. Her blast crisis was accompanied by characteristic chromosome changes, such as trisomy 1, trisomy 17, and multiple Ph chromosomes.

Chronic granulocytic leukemia: correlation of blastic transformation type with karyotypic evolution

Over a 3-year period, 26 patients with Philadelphia chromosome-positive chronic granulocytic leukemia were studied cytogenetically in both the chronic and blastic transformation phases of the disease; a further three patients were studied only after blastic transformation. Sixteen were considered to have adequate evidence of the type of transformation and form the basis of the report, where chromosome changes have been correlated with the morphological type of blastic transformation. Seven patients developed a myeloblastic transformation, seven a lymphoblastic transformation, and two an erythroblastic transformation. All patients in the myeloid group acquired one or more of the nonrandom changes associated with CGL blastic transformation, viz. +8,i(17q), +19, +22q-. Patients in the lymphoblastic group acquired structural abnormalities, apparently random in nature and usually in a small percentage of cells. The two patients with erythroblastic transformation developed markedly hyperdiploid cells (greater than 50 chromosomes) with both numerical and structural abnormalities. Patients in the lymphoblastic group appeared to have a slightly better prognosis than the myeloid group, whilst the patients with erythroblastic transformation had a very poor prognosis.

Chromosomal characteristics of chronic and blastic phases of Ph-positive chronic myeloid leukemia

To evaluate the appearance of chromosome changes, in addition to the Philadelphia (Ph) chromosome, as predictive and diagnostic parameters of transformation in chronic myeloid leukemia (CML), such changes were analyzed in the chronic phase (CP) and compared with those of the blastic phase (BP) of CML. The common chromosome changes observed in the CP were loss of a Y (-Y), trisomy 8 (+8), an isochromosome for the long arm of chromosome #17 [i(17q)], a double Ph (+Ph), reciprocal translocations, and partial deletions. In most patients with chromosome changes in addition to the Ph, the percentage of abnormal clones increased steadily during the CP and was accompanied by other chromosome changes shortly before or at the onset of the BP, except for cases with -Y or i(17q) clones. In general, most chromosome changes observed shortly before or at the BP were complex. These facts suggest that complex chromosome changes could be utilized as predictive and diagnostic parameters of blastic transformation in CML.

The incidence, type, and subsequent evolution of 14 variant Ph1 translocations in 180 South African patients with Ph1-positive chronic myeloid leukemia

A Philadelphia (Ph1) chromosome translocation was found in 180 of 198 cases of chronic myeloid leukemia (CML). A standard t(9;22) was present in 166 patients, 83 of whom were black, 79 white, and 4 of "mixed" ancestry; whereas a variant Ph1 translocation was detected in 14 patients (7.8%), 11 of whom were black and only 3 white. There was a higher frequency of a variant Ph1 among black patients compared with whites. The significantly higher frequency of a variant among our patients compared with surveys from elsewhere could be due to differing environmental agents. Simple variants were detected in four patients. Complex variants were found in eight cases; in one of these patients, only chromosomes #9 and #22 were involved, but a complex rearrangement of chromosome #9 had occurred. A "masked" Ph1 translocation was detected in two cases, both of which showed monosomy #22 because the Ph1 chromosome was incorporated or interchanged with chromosome #9. Karyotypic evolution of the Ph1-positive cell line was observed more frequently in the variant group (71.4%) than the standard group (29.5%). This difference was significant (p less than 0.005). There was no difference in the type of clonal changes seen in standard and variant groups. The majority of clonal changes were observed during the acute stage in both groups. In the variant group, there was no obvious correlation between the type of variant, type of clonal change, blast morphology, or survival. Their initial survival pattern resembled that of Ph1-negative cases, but those patients who survived longer than 1 year showed a survival trend similar to standard Ph1-positive cases. Possible explanations for the specificity of chromosome #22 involvement and the constancy of the 22q11 breakpoint in all these variant translocations are discussed.

Investigations on karyotype evolution in patients with chronic myeloid leukemia (CML)

In an attempt to relate karyotype evolution to clinical and hematological data serial chromosomal analyses were performed in 31 patients with chronic myeloid leukemia (CML), both in chronic and acute phases. Our results in Philadelphia chromosome (Ph1)-positive CML are in line with karyotype profiles described in the literature. In addition, we report on chromosomal findings in 4 cases of Ph1-negative disease, one presenting with an iso17q chromosome in the positive CML. The same chromosomal abnormality was observed in a small population of Ph1-negative cells present in one of two patients with mixed Ph1-positive/Ph1-negative CML. The first case of a female patient with the loss of a sex chromosome in Ph1-positive cells is reported. Two patients with unusually long and mild chronic phases despite the presence of trisomy 8 in their karyotypes are described. Our findings suggest that the order of appearance of additional chromosomal changes of CML is of prognostic significance for the progression and the clinical picture of the disease.

Cytogenetic studies of bone marrow and extramedullary tissues and clinical course during metamorphosis of chronic myelocytic leukemia

Of 33 consecutive patients with chronic myelocytic leukemia, examined during metamorphosis, 82% showed chromosome abnormalities in addition to the Ph1. Aberrations most frequently encountered were +8 (39%), +22q - (30%), and i(17q) (18%). Translocations other than the Ph1 were observed in four cases and - Y clones in four cases. Discrepancies in the cytogenetic pattern between bone marrow and extramedullary tissues or blood were noted in a total of 15 patients. In six cases, transformation occurred in extramedullary organs at a time when it was not present in the marrow. In three cases the bone marrow transformation was preceded by a lymph node blastic infiltrate; in one case, by a skin infiltrate; and in one case, by a subdural blastoma. Clonal abnormalities additional to the Ph1 were identified in the tumor tissue from all these cases. Patients with primary extramedullary transformation tended to have a lower median age at onset of metamorphosis, shorter survival, and higher incidence of chromosome abnormalities than the cases without extramedullary involvement. Patients with only Ph1-positive cells and no other anomalies had a slightly longer duration of metamorphosis and longer total survival. Basophilia and thrombocytopenia were more marked in cases with i(17q) than in the rest of the series.

Chronic myelogenous leukemia with a Philadelphia chromosome resulting from a complex translocation (2; 9; 22), following an undifferentiated acute leukemia

This case report concerns a patient with acute leukemia considered at diagnosis to be undifferentiated. Unfortunately, because of the failure of the culture, a cytogenetic evaluation was not possible at that stage. A full remission was induced, but 17 months after the onset of the disease the patient developed chronic myelogenous leukemia. The karyotypes prepared at that time and during the follow-up revealed the presence of a Philadelphia chromosome (Ph1) in all examined cells. This Ph1 resulted from a complex translocation involving chromosomes No. 2, 9, and 22.

Chromosomes and causation of human cancer and leukemia. IL. Therapeutic and prognostic value of chromosomal findings during acute phase in Ph1-positive chronic myeloid leukemia

The therapeutic response and survival after the onset of the acute crisis in 64 patients with Ph1-positive chronic myeloid leukemia (CML) were correlated with the chromosomal findings during the course of the acute phase. The patients were divided into three groups on the basis of the chromosome findings in the bone marrow, blood, and spleen: i.e. those with only a Ph1 (PP), those having two types of clones, i.e. one clone with only a Ph1 and another with additional karyotypic changes (AP), and those with only abnormal clones containing karyotypic abnormalities in addition to the Ph1 (AA). The number of patients in each group was: 22 in PP, 25 in AP and 17 in AA. The results were as follows: (1) The percentage of patients with a good therapeutic response was 77 per cent (17/22) in PP, 60 per cent (15/25) in AP and 29 per cent (5/17) in AA and 2). The median survival after the onset of the acute crisis was 148 days (4.9 months) in PP, 183 days (6.1 months) in AP and 53 days (1.8 months) in AA. Statistically, there was a significant difference between the AA and the other two groups (P less than 0.001). Our observations suggest that the lack of a clone with only a Ph1 during the course of the acute phase (AA) indicates an unfavourable response and a poor prognosis after the onset of the acute crisis in CML.

Chromosome banding patterns in patients with chronic myelocytic leukemia

One hundred and nine patients with Ph1-positive chronic myelocytic leukemia were cytogenetically studied with banding methods. Seventy-eight patients were studied in the chronic phase and 39 patients in the blastic phase. The standard translocation was present in 107 cases. Two patients showed complex translocations involving chromosomes No. 6, 9, 22, 11 and No. 9, 22, 11, respectively. Ph1-negative cells were detected in 8 cases (7%). Chromosome aberrations in addition to the Ph1 chromosome were observed in 6 cases (8%) during the chronic phase. The karyotypic findings during the blastic phase were similar to those reported in the past [trisomy 8, iso(17q), and a second Ph1]. The significance of Ph1-negative cells, the geographic heterogeneity of the chromosomal aberrations, the effect of chemotherapy on the appearance of new clones, and the importance of the materials and methods used for the comparison of cytogenetic patterns at different laboratories are discussed.

Karyotype analysis in acute nonlymphocytic leukemia (ANLL): comparison with ethnic group, age, morphology, and survival

The karyotype, leukemia cell morphology (FAB classification), ethnic group, age, sex, and survival were compared in 60 patients with acute nonlymphocytic leukemia (ANLL), to determine their diagnostic and prognostic significance. An ethnic age difference was observed; a significantly greater number of black patients were children. The majority of children were males. A higher frequency of chromosome abnormalities was detected in children, yet they survived longer than adults. A specific, significant association between a (8; 21) karyotype and M2-ANLL was confirmed; four of ten patients with M2-ANLL showed this translocation. The more mature morphology of M2-ANLL was associated with a longer survival irrespective of karyotype, ethnic group, and age. The specificity of t(15; 17) in M3-ANLL and nonrandom monosomy 7 in preleukemic children was confirmed. Patients, particularly adults, with normal karyotypes tended to survive longer than those with abnormal karyotypes. The patient's age and the differentiative capacity of the leukemic cell appear to be as important as the karyotype in determining survival. The nonrandom association of certain chromosome aberrations in ANLL appears to be worldwide.

Variant Ph1 translocations in CML and their incidence, including two cases with sequential lymphoid and myeloid crises

A serial cytogenetic study of 110 cases of chronic myelogenous leukemia (CML) has been performed with G- and/or Q-banding techniques with the following results. (1) Seven out of the 110 cases were karyotypically normal. (2) A variant Ph1 translocation was observed in three cases. In one case, the leukemic cells contained two reciprocal translocations, i.e., a t(3;9) (q21;q34) and a t(17;22)(q21;q11); therefore, a Ph1 chromosome was masked by a translocation of the deleted material from the 17q onto the band q11 of the long arm of a chromosome No. 22. In the second case, a variant Ph1 translocation involved chromosomes No. 9, 20, and 22, resulting in a karyotype interpreted as 46,XX,t(9q+;20q+;22q-); in this rearrangement, one of the segments, i.e., 9q31 or 9q33, seemed to be interstitially deleted and inserted into the interstitial region (q11) of a chromosome No. 20 and the 22q11 leads to qter was translocated onto the 9q. This is the first case in which chromosome No. 20 was involved in a variant Ph1 translocation. In the third case, the karyotype of leukemic cells was interpreted as 46,XX,t(5;9;22)(q13;q34;q11). (3) The frequency of Ph1-negative CML and that of Ph1-positive CML with various types of Ph1 translocation from 15 studies reported as series of 25 or more cases, including the present study, have been tabulated. The incidence of a variant Ph1 translocation was 4.1% (42/1027 cases of Ph1-positive CML); of the 42, 13 were of a simple type and 29 of a complex type. (4) In one case of the present study, a masked Ph1 by a translocation of material onto the short arm of the 22q- was observed in the blastic crisis but not in the chronic phase. From the present study and a review of the published cases, it appears that the incidence of such a "masked" Ph1, which cannot be detected by conventional Giemsa staining, is less than 0.6% in CML cases. (5) The first and the second cases with a variant Ph1 translocation mentioned above developed a myeloid blastic crisis after the induction of remission of a lymphoid blastic crisis. For the present, it is unclear whether the occurrence of such blast cells in the two cases and the cytogenetic findings are coincidental. However, the evidence supports the notion of "lymphoid-myeloid" multipotentiality of certain leukemic cells.

Chromosomal, morphological and clinical correlations in blastic crisis of chronic myeloid leukaemia: a study of 69 cases

The karyotypic pattern in 69 patients with Ph1-positive chronic myeloid leukaemia (CML) was investigated during the blastic phase (BC) and correlated with survival and certain parameters of potential prognostic significance, including blast morphology, basophilia and thrombocytopenia. There was no difference in median survival in BC between patients with and without aberrations in addition to the Ph1. Nor were there any differences in this respect among patients with the specific aberrations +Ph1, +8, iso(17q), or other abnormalities. There was no correlation between the incidence of thrombocytopenia and any particular karyotypic change. However, the incidence of basophilia was a characteristic feature for patients with an iso(17q). The survival time in BC was considerably longer in patients with a lymphoid morphology of the blastic cells compared to the myeloid varieties, and within the myeloid varieties the survival in BC was longer in patients with granular differentiated blasts than in those with granular atypical blast cells. No obvious correlation was apparent between blast morphology and karyotypic pattern. However, a pattern was discernible regarding survival and certain chromosomal changes within some morphologic groups: in patients with granular differentiated and lymphoid morphology, the median survival in BC was considerably longer when the bone marrow cells had a Ph1 as the sle abnormality compared to patients who had additional aberrations.