Cytogenetic survey of 53 Moroccan patients with acute myeloblastic leukemia

Cytogenetic profile of a representative cohort of young adults with de novo acute myéloblastic leukaemia in Morocco

BACKGROUND

We analyzed the cytogenetic characteristics of a representative population of young adults with de novo acute myéloblastic leukemia (AML) treated in a single center institution.

METHODS

Patients with de novo AML included were aged between 20 and 60 years. Cytogenetic analysis was done at diagnosis. Twenty cells were analyzed, although examination of lower numbers of metaphases was also acceptable if an abnormal clone was detected.

FINDINGS

From 1/1/04 to 31/12/2014, among 1315 adult patients, 1055 (80%) patients were aged between 20 and 60 years. Karyotype was done in 927 (88%) patients and cytogenetic analysis failed in 32 cases (3·4%). Clonal abnormalities were observed in 520 (58%) patients. 175 (19·5%) were classified in the favorable group, 609 were in the intermediate group and 111 (12·5%) were in the adverse group. The most frequent chromosomal abnormality observed was t(8;21) in 112 (12·5%). Thirty three (3·7%) patients had t(15;17) and 30 (3·3%) had inv16, trisomy 8 was found in 47 (5·2%), 11q23 rearrangements in 32 (3·6%), 67 (7·4%) had a complex karyotype, -5/del(5q) and -7/del(7q) were seen in, respectively, 11(1%) and 27 (3%). Monosomy occurred in 115 (13%) patients, 70 (8%) responded to the definition of monosomal karyotypes.

INTERPRETATION

This is the largest study done in Morocco, Africa and Middle East. Epidemiological studies involving different ethnic populations and geographic regions of the world should help unfold the true nature of environmental and genetic interplay in the development of AML. Our cytogenetic profile reveals some particularities when compared to other populations; it does not seem to be similar neither to eastern or western countries.

Complex Karyotype in Hematological Diseases: A 6-Year Single Centre Study from Pakistan

BACKGROUND

Most of the hematological disorders are heterogenous with regard to morphology, immunophenotype, and genetic rearrangements. Multiple recurrent chromosomal aberrations have been identified by conventional cytogenetic analysis, which is now widely recognized as one of the most important diagnostic and prognostic determinants in these patients. Though rarer, complex karyotype has been associated with worst prognosis.

MATERIALS AND METHODS

A total of 1185 bone marrow or peripheral blood cytogenetics samples were taken with different hematological diseases. They included both benign and malignant disease entities. In each case, cells were cultured and conventional cytogenetic analysis was performed.

RESULTS

Among 1185 subjects, 41 (3.4%) patients possessed complex cytogenetic abnormalities. Out of these 41, 33 (80%) were males. The mean age was 37 years (median age 39 years). Myelodysplastic syndromes had the most numbers of complex karyotypes (8%), followed by acute myeloid leukemia (7%) and acute lymphoblastic leukemia (4%). Also we found few patients with acute promyelocytic leukemia, aplastic anemia , chronic myeloid leukemia, and diffuse large B cell Lymphoma possessing complex karyotype. Frequencies of different cytogenetic abnormalities were assessed with respect to disease as well as independently. Trisomy 21 was the most common chromosomal abnormality found in 28% of patients.

CONCLUSION

Complex karyotype was most frequently associated with myelodysplastic syndromes and acute myeloid leukemia. Trisomy 21 and deletion 5q were the commonest cytogenetic abnormalities found. We also assessed complex karyotype in benign diseases and detected one patient of aplastic anemia with complex karyotype. This is the first study highlighting the presence of complex karyotypes in hematological disorders in our region.

Cytogenetic profile of a large cohort of Tunisian de novo acute myeloid leukemia

BACKGROUND

Cytogenetic data are essential not only for the diagnosis of acute myeloid leukemia but also for the evaluation of prognosis. Large systematic studies of cytogenetic aberrations in patients with acute myeloid leukaemia (AML) from Arab countries are not available.

METHODS

We analysed 631 consecutive newly diagnosed AML patients by conventional cytogenetics and compared our results with reports from other regions of the world. There were 97 (15·4%) children and 534 (84·6%) adults.

RESULTS

Abnormal karyotypes were found in 397 (62·9%) of all cases. T(15;17) and t(8;21) were the most frequent chromosomal abnormalities observed in 83 (13·2%) and in 78 (12·4%) patients, respectively. -5/del(5q) and -7/del(7q) were less frequent, seen in only 14 (2·2%) and 19 (3%) cases, respectively. Trisomy 8 was found in 44 (7%) of our patients followed by 11q23 rearrangements seen in 24 (3·8%) and then by inv(16) observed in only 22 (3·5%) of all cases. Unusual or novel cytogenetic abnormalities were found in 107 (17%) of our patients.

DISCUSSION

Although we confirmed, as usually described, that some recurrent cytogenetic abnormalities are correlated with the FAB subtypes, we noted however that some of them vary in frequency among different geographical areas and ethnic groups. This finding suggests a geographic heterogeneity in the pathogenesis of AML but more extensive epidemiological studies are required to confirm this.

del(15q) is a recurrent minor-route cytogenetic abnormality in the clonal evolution of chronic myelogenous leukemia

The del(15q) chromosomal abnormality is known to occur in acute leukemias, but has rarely been described in chronic myelogenous leukemia (CML). Described here are five cases of CML associated with del(15q): four men and one woman. Bone marrow aspirate smears showed increased blasts in all cases at the time of del(15q) detection, in accelerated phase in two cases and myeloid blast phase in three. Conventional cytogenetic analysis showed t(9;22) and del(15q), as well as other inconsistent clonal abnormalities. All patients received imatinib mesylate; four received additional chemotherapy, and two had allogeneic stem cell transplantation (ASCT). Of the three patients who did not receive ASCT, one died, one was in persistent blast phase, and one was in clinical remission with molecular evidence of residual disease at 16, 6, and 34 months, respectively, after identification of the del(15q). Of the two patients who had ASCT, one died and one was in clinical remission with molecular evidence of disease at 15 and 64 months, respectively, after identification of the del(15q). These findings indicate that del(15q) is a recurrent cytogenetic abnormality that may be seen at initial presentation of advanced disease or may emerge during disease progression. Del(15q) appears to be associated with a poor prognosis in CML.

Deletion 15q as the sole abnormality in acute myeloid leukemia: report of three cases and review of the literature

Deletions within the long arm of chromosome 15, a recurrent abnormality in myeloid malignancies, have been reported previously as a sole abnormality in only eight cases of acute myeloid leukemia (AML). We describe three new cases of AML with this abnormality, all adult women (age, 41-66 years). Two cases were acute myelomonocytic leukemia (FAB AML-M4), and one was acute myeloblastic leukemia with maturation (FAB AML-M2). The deletion was identified at initial diagnosis in one patient and at relapse in the other two. Although all received aggressive therapy, their survival was short. Taken together with the eight previously reported cases, we conclude that deletions in chromosome 15 are associated with AML, both in cases that arise de novo or in the setting of a myeloproliferative disorder or myelodysplastic syndrome. These cases often show features of myelomonocytic or monocytic differentiation. The prognosis is poor, with survival similar to other AML cases with unfavorable cytogenetic changes.

Deletion of chromosome arm 15q in a case of minimally differentiated hypoplastic AML-M0

Deletion of the long arm of chromosome 15 is known as a rare but recurrent chromosomal abnormality in myeloid malignancies. We report a novel case of minimally differentiated hypoplastic acute myeloid leukemia (AML M0) in a patient who initially had a normal karyotype, but clonal interstitial deletion of chromosome 15, del(15)(q11.2q22), coincided with increment of leukemic cells a year later. We also summarize 18 published cases with myeloid malignancies and this chromosomal abnormality.

Cytogenetic, morphological, and immunophenotypic patterns in Omani patients with de novo acute myeloid leukemia

Chromosome aberrations observed at diagnosis are considered to be the most valuable prognostic factors in acute myeloid leukemia (AML). Some specific aberrations vary in frequency among different geographical areas and ethnic groups. There are only limited studies on the role of such variability in AML patients. Here, we report the results of a cytogenetic study on 63 ethnic Omani patients with de novo AML: 18 children (<or=16 years) and 45 adults. By sex, 41 were male and 22 female; median age at diagnosis was 25 years. The morphological diagnosis was based on the French-American-British (FAB) WHO criteria. Chromosome abnormalities were present in 39 of 63 patients (62% overall, or 44% for adults and 18% for children). Karyotypes with a sole abnormality accounted for 20 of 63 patients (32%). Chromosome abnormalities were more common in patients with the FAB-M2 subtype (15 of 22; 68%), which was also the most frequent subtype observed (22 of 63; 35%). Among the normal karyotypes (24 of 63; 38%), M2 subtype was the also most frequent (7 of 24; 29%), followed by M4 (4 of 24; 17%). Balanced translocations, t(8;21) and t(15;17) were observed in 7 of 63 (11%) and 6 of 63 (10%), respectively. Inv(16) was seen in 2 of 63 (3%). Trisomy 8 was the most frequent numerical anomaly, found in 7 of 63 (11%). Monosomy 7 was seen in 3 of 63 (5%). The patterns in our study were similar to those reported from Saudi Arabia and Kuwait, but the frequency of abnormalities varied. Our population differed morphologically, with the M2 subtype as most common, whereas M4 and M3 were more commonly in those reports. A comparison of our findings was made with other geographic and ethnic groups. This is the first systematic cytogenetic study of an ethnic Omani population.

Cytogenetic and morphological findings in 166 patients with de novo acute myeloid leukemia in southern Brazil

Chromosomal rearrangements correlate with different clinical subgroups of blood disorders. Some of these chromosomal abnormalities are found in individuals from specific geographical areas and ethnic groups. A high incidence of t(15;17) translocation has been observed, for example, in the Hispanic populations of the United States and Spain. The same occurs in South America, due to the rich diversity of ethnic groups that colonized the region. We performed a cytogenetic analysis of 166 patients at the Division of Hematology of Hospital de Clínicas de Porto Alegre between 1990 and 2002. Those patients who met the criteria for de novo acute myeloid leukemia (AML) and whose karyotypes could be successfully determined were included in the study. The karyotypes of each patient and the French-American-British (FAB) criteria for the diagnosis of AML were reviewed. Chromosomal abnormalities were identified and classified according to ISCN 1995. Chromosomal abnormalities were found in 53.6% of cases. Abnormalities were significantly more common in the FAB-M3 group (70.3%). The most common balanced translocation was t(15;17), observed in 13.25% of the patients.

Deletion of chromosome 15 represents a rare but recurrent chromosomal abnormality in myelocytic malignancies

We report on three cases with myelocytic malignancies cytogenetically characterized by a deletion of chromosome 15 occurring as the sole cytogenetic aberration. The deletions were defined as del(15) (q12q21) (two cases) and del(15)(q11q21) (one case). Cytogenetic analysis was supplemented by fluorescence in situ hybridization (FISH) using a chromosome 15 specific whole chromosome painting probe and probes hybridizing to the UBE3A gene on 15q11~q13, the PML gene on 15q22, and the telomeric region of 15q. Hereby, an interstitial deletion of 15q including UBE3A, but not PML and the telomeric region of 15q could be demonstrated. Two of our patients were diagnosed as acute myelocytic leukemia (AML) with bone marrow dysplasia classified as AML-M6 and AML-M4, respectively, according to the French-American-British classification; the third patient suffered from a chronic myelomonocytic leukemia (CMMoL). In two cases, the aberration was found at the time of primary diagnosis, whereas the third case showed the del(15) only during relapse of leukemia. Both cases with acute leukemia did not adequately respond to intensive chemotherapeutic treatment and died 13 and 11 months, respectively, after primary diagnosis. Our findings and the data of five previously published cases with an isolated del(15) indicate that: 1) del(15) represents a rare but recurrent abnormality in myelocytic hemopathies; 2) in our cases, del(15) was interstitial and included the region 15q11~q13/UBE3A, but not 15q22/PML and the telomeric region of 15q as shown by FISH; 3) del(15) occurs frequently in disorders with myelodysplastic or myeloproliferative features and may therefore affect early hematopoietic progenitor cells; and 4) del(15) may occur during disease progression and is often associated with an unfavorable prognosis.

Cytogenetic analysis in 139 Tunisian patients with de novo acute myeloid leukemia

This paper presents the results of a cytogenetic analysis in 139 Tunisian patients with de novo acute myeloid leukemia (AML), including 27 children aged 1-15 years and 112 adults. Mean age was 32 (range 1-75) and the M/F ratio was 1.43. Of our patients, 45% had apparently normal karyotypes. Acquired chromosome aberrations were found in 77 (55% ) patients. t(8;21) was identified in 27 patients (19%); t(15;17) in 13 patients (9%); deletion 7q or monosomy 7 in seven patients (5%); +8 in seven patients (5%); abnormal 16 in four patients (3%); 11q23 rearrangements in two patients (2%) and del(5q), in one patient (1%). The remaining 16 patients had miscellaneous clonal abnormalities. Specific translocations associated with the FAB type were found: t(8;21) with AML2 and t(15;17) with AML3. We concluded that our study in a Tunisian population confirmed the relation between some specific abnormalities and the FAB classification. We found a higher incidence for t(8;21) than usually described.