Cytogenetic characterization of ten cases of Ph1-positive acute myelogenous leukemia

Philadelphia chromosome positive myelodysplastic syndrome and acute myeloid leukemia—retrospective study and review of literature

We conducted a retrospective study to define the significance of Philadelphia chromosome (Ph) in myelodysplastic syndrome and acute leukemia in the adults at this institution and the literature was reviewed. One hundred forty-eight cases of t(9;22)(q34;q11) were identified for the period September 1993 through August 2001. The presentation of 124 cases (84%) was that of typical CML in chronic phase. Nineteen cases (13%) presented as de novo ALL, two cases (1%) presented as de novo AML and three cases (2%) presented as myelodysplastic syndrome (MDS). The estimated incidences of t(9;22)(q34;q11) in ALL and AML are 21 and 0.6%, respectively. Ph+ AMLs are increasingly being reported with either M-BCR or m-BCR gene rearrangements, similar to those found with Ph+ ALL lending support to the notion that Ph+ AMLs are distinct entities and not merely blastic phases of undiagnosed CML. This is further supported by the existence of Ph+ MDS cases.

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).

Significance of chromosomal changes in patients of different age groups with acute leukemia

Chromosome abnormalities have been observed in about 50% of patients with acute leukemia. There have been several published reports which emphasized the chromosomal changes in relation to the age of the patient and the morphologic type of acute leukemia. All observations suggest that there are both age related similarities and differences. The karyotype is an important independent prognostic factor in acute leukemia; however, age alone (especially above age 70) is the single most important factor for a poor prognosis.

Specific chromosomal changes in patients with acute nonlymphocytic leukemia from India

We analysed forty consecutive patients with acute nonlymphocytic leukemia (ANLL) using methotrexate cell synchronization and 24 h-unstimulated cultures of bone marrow cells to determine the incidence of chromosomal aberrations and the association of specific anomalies with FAB morphological subtypes, in an Indian population. All patients demonstrated an abnormal karyotypic pattern. The specific chromosomal changes viz., t(9;22), t(8;21), t(15;17), t/del(11q), 12p- were found in M 1(3/5), M2(8/15), M3(8/8), M4(1/1) M5(2/4) and M2Ba(1/1) (M2 with Basophilia) patients. Abnormalities of 11q were also noted in two M2 patients showing monocytic involvement. A translocation involving chromosomes 6 and 9 was seen in one patient with M1 and two patients with M2. An inv(16) was observed in M1 (one case), M2 (two cases) and M6 (one case). A del(16) was noted in an M4 case. Although t(9;22) is frequently associated with M1 patients, it was also detected in M2 (two patients) and M4 (one patient). Among all the FAB specific anomalies described above, t(8;21) and t(15;17) were observed only in M2 and M3 patients, respectively. Interestingly, one M2 patient had two independent clones, one with t(8;21) and t(9;11). Deletion or translocation involving 11q was found in a Ph positive M4 patient. New structural rearrangements such as t(1;7) (q32;q36) in association with t(8;21), and t(14;22) (q32;q11) in association with del(11)(q23) were detected in a M2 and a M5 patient, respectively. In conclusion, our studies have revealed that the incidence of FAB specific abnormalities viz., t(8;21); t(15;17), t(9;22), t/del(11q) and also other recurrent anomalies viz., -7/7q-, +8 is much higher in our patients, as compared with other countries. This difference may be attributed to the influence of differential environmental exposure to unknown carcinogenic agents.

Transposition of c-abl oncogene in a case of masked Ph chromosome duplicated in blastic phase

A female with chronic myelocytic leukemia (CML) in blastic phase (BP) showed a masked Ph chromosome that had originated by a translocation between chromosomes 8 and 22, with no obvious involvement of chromosome 9. A duplication of the masked Ph and trisomy 13 were present as additional anomalies. The karyotype on peripheral blood unstimulated cultures was 48,XX,t(8;22)(p12;q11),+13,+der(22) t(8;22)/47,XX,t(8;22)(p12;q11),+der(22)t(8;22). While the duplication of the Ph is a frequent finding in BP of CML, we did not find any other case in the literature with duplication of a masked Ph. In situ hybridization with c-abl and bcr probes showed that a 3' bcr sequence was translocated to the der(8) chromosome, while the c-abl oncogene was transposed to the masked Ph.

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.

The significance of cytogenetic findings of erythroid colonies derived from a Ph+ ALL patient: fundamental differences between Ph+ ALL and blastic phase CML

Cytogenetic analysis was performed on colonies from erythroid burst-forming units (BFU-E) derived from bone marrow (BM) cells of a Ph-positive acute lymphocytic leukemia (Ph+ ALL) patient. A normal diploid karyotype was revealed in all 15 metaphases that could be analyzed in the erythroid colonies. Previous cytogenetic analyses of erythroid colonies obtained from BM cells of patients with Ph+ chronic myelogenous leukemia (CML) revealed that Ph-positive karyotypes were predominant in all 11 cases. Two of them were also examined in blastic phase (BP) and showed 100% Ph+ cells in BFU-E-derived colonies. The present findings suggest that the leukemic process of Ph+ ALL does not involve the erythroid series, which is in contrast to the involvement in CML. This is considered to be a fundamental difference between Ph+ ALL and the blastic phase of CML (BP CML). Clinically, cytogenetic analysis of erythroid colonies from BM cells may constitute a valuable approach for the differential diagnosis between Ph+ ALL and the BP of Ph+ CML.

Acquisition of a Philadelphia chromosome concomitant with transformation of a refractory anemia into an acute leukemia

The authors present a case of Philadelphia (Ph1) positive acute myeloblastic leukemia (AML) following a refractory anemia with excess of blasts (RAEB) that had been Ph1-negative for 17 months. During the transformation of RAEB into AML, the Ph1 was discovered in 100% of the examined cells. With therapy a partial remission was obtained, during which some 46,XY cells reappeared mixed with Ph1 cells along with a new clone: 47,XY,+11 originating from a Ph1-negative cell. During the terminal blast crisis, the karyotype returned to 46,XY,Ph1. The AML lasted 21 months. The authors discuss: (1) the significance of Ph1-positive AML with a review of the literature; (2) the de novo acquisition of a Ph1 during the course of a blood disorder; and (3) the meaning of a second abnormal clone originating from 46,XY cells.