Cytogenetic, cytomorphologic, and immunologic analysis in 55 children with acute lymphoblastic leukemia

Clinical and Cytogenetic Characteristics of Children With Leukemia 20-Year Retrospective Study

Acute leukemias are the most common malignant diseases in childhood. The aims of this retrospective cohort study were to investigate the frequency of cytogenetic abnormalities in acute pediatric leukemia; the correlation between cytogenetic abnormalities and 5-year survival; and the correlation between cytogenetic abnormalities and clinical and laboratory features. We included 105 patients; acute lymphoblastic leukemia (ALL) had 80.9% patients, B-cell lineage ALL (B-ALL) 84.7% of them, and T-cell lineage (T-ALL) 15.3%. The overall 5-year survival for B-ALL was 85.9% and for T-ALL was 84.6%. The most common cytogenetic abnormalities in patients with B-ALL were t(12;21)(p13.2;q22.1); ETV6-RUNX1 with 22.2% and hyperdiploidy with 19.4%. Our survival analysis showed that t(12;21)(p13.2;q22.1); ETV6-RUNX1 and t(1;19)(q23;p13.3); TCF3-PBX1 had the best 5-year survival with 100% of patients surviving, whereas t(v;11q23.3); KMT2A rearranged had the worst 5-year survival of just 33.3% of patients surviving after 5 years. We found no difference in 5-year survival in B-ALL when comparing clinical features. Acute myelogenous leukemia had 20 patients with 70.6% 5-year survival. The most common cytogenetic abnormality in acute myelogenous leukemia was t(8;21)(q21;q22.1); RUNX1-RUNX1T1 (20%). In conclusion, this study showed the correlation of different cytogenetic abnormalities with 5-year survival in B-ALL patients. Such correlation was not found when comparing clinical features and 5-year survival of patients with B-ALL. This emphasized the significance of cytogenetic analysis in pediatric leukemia.

Importance of FISH combined with Morphology, Immunophenotype and Cytogenetic Analysis of Childhood/ Adult Acute Lymphoblastic Leukemia in Omani Patients

Genetic changes associated with acute lymphoblastic leukemia (ALL) provide very important diagnostic and prognostic information with a direct impact on patient management. Detection of chromosome abnormalities by conventional cytogenetics combined with fluorescence in situ hybridization (FISH) play a very significant role in assessing risk stratification. Identification of specific chromosome abnormalities has led to the recognition of genetic subgroups based on reciprocal translocations, deletions and modal number in B or T-cell ALL. In the last twelve years 102 newly diagnosed childhood/adult ALL bone marrow samples were analysed for chromosomal abnormalities with conventional G-banding, and FISH (selected cases) using specific probes in our hospital. G-banded karyotype analysis found clonal numerical and/or structural chromosomal aberrations in 74.2% of cases. Patients with pseudodiploidy represented the most frequent group (38.7%) followed by high hyperdiploidy group (12.9%), low hyperdiploidy group (9.7%), hypodiploidy (<46) group (9.7%) and high hypertriploidy group (3.2%). The highest observed numerical chromosomal alteration was high hyperdiploidy (12.9%) with abnormal karyotypes while abnormal 12p (7.5%) was the highest observed structural abnormality followed by t(12;21)(p13.3;q22) resulting in ETV6/RUNX1 fusion (5.4%) and t(9;22)(q34.1;q11.2) resulting in BCR/ABL1 fusion (4.3%). Interestingly, we identified 16 cases with rare and complex structural aberrations. Application of the FISH technique produced major improvements in the sensitivity and accuracy of cytogenetic analysis with ALL patients. In conclusion it confirmed heterogeneity of ALL by identifying various recurrent chromosomal aberrations along with non-specific rearrangements and their association with specific immunophenotypes. This study pool is representative of paediatric/adult ALL patients in Oman.

Cytogenetic Profile of Childhood Acute Lymphoblastic Leukemia in Oman

BACKGROUND

Chromosomal abnormalities have important diagnostic and prognostic significance in acute lymphoblastic leukemia (ALL). The purpose of this study was to define and classify the frequency and type of chromosomal abnormalities among newly diagnosed children with ALL and compare the results with those reported from other geographical regions of the world.

METHODS

Bone marrow chromosomal studies with GTG banding were performed in untreated ALL pediatric patients aged from 7 days to 14 years.

RESULTS

Among Omani children examined with ALL, 47 (81%) patients yielded results, with 26 (55.3%) showing an abnormal karyotype [10 (21.3%) pseudodiploid, 2 (4.3%) hypodiploid and 14 (29.7%) hyperdiploidy] and 21 (44.6%) had normal diploidy. Structural abnormalities were observed in 16 (34%), of which 11 (23.4%) cases were translocations, the most frequent being t(9;22) observed in three (6.4%) of our patients. Uncommon translocations such as t(9;15)(p11;q10), t(3;6)(p12;q11), t(1;6)(?31;?q23), t(1;19)(q12;q12), der(18)t(12;18)(q11;p11), and other structural aberrations add(2)(q22), add(6)(q16), add(18)(q22), add(14)(q32) along with deletions del(10)(q22), del(12)(p11), del(12)(p12), del(18)(q11) were also observed.

CONCLUSIONS

The study showed a good correlation and concordance between the ploidy distribution by cytogenetics and flow cytometry. The patterns of chromosomal anomalies in our patients showed some variations in the frequency of aberrations reported. It is therefore necessary that newer techniques like fluorescence in situ hybridization (FISH) along with reverse transcriptase polymerase chain reaction (RT-PCR) and spectral karyotyping will help us identify chromosomal aberrations not detected by conventional cytogenetic methods in the near future. To our knowledge, this is the first report from the Middle East of a cytogenetic study on childhood ALL.

Cytogenetics in childhood acute lymphoblastic leukemia in Taiwan: a single-institutional experience

The aim of the study was to define the frequency and types of acquired chromosomal aberrations in a group of Taiwanese children with ALL. The sample population consisted of 78 patients under 18 years of age with newly diagnosed ALL who underwent cytogenetic studies at diagnosis and had adequate metaphase chromosomes for analysis at the authors' hospital from 1993 to 2001. Metaphase chromosomes were banded using the conventional trypsin-Giemsa banding technique. Analysis of ploidy revealed 16 (20.5%) patients with normal diploidy, 28 (35.9%) with pseudodiploidy, 6 (7.7%) with hyperdiploidy (47-50), 19 (24.4%) with hyperdiploidy (> 50), and 9 (9.4%) hypodiploidy. Near-haploidy was not observed. Of the patients with abnormal karyotypes, recurrent structural abnormalities were determined in 31 (50%) cases, with the most frequent t(9;22). In conclusion, the frequency and type of acquired chromosomal aberrations found in these Taiwanese children with ALL are similar to those reported in the literature.

Cytogenetics in acute lymphoblastic leukemia in Mexican children: an institutional experience

BACKGROUND

Cytogenetic studies in acute lymphoblastic leukemia (ALL) have identified numerical and structural chromosomal abnormalities related to the disease's pathophysiologic characteristics. These findings correlate with prognosis and response to treatment in ALL patients. The purpose of this study was to define the frequency of chromosomal abnormalities in a group of Mexican children with ALL and to compare these data with those reported in the literature.

METHODS

Bone marrow chromosome studies with GTG bands were performed in 150 pediatric patients with ALL who were naive to antileukemic treatment and aged from 5 months to 16 years; the majority was diagnosed as L1.

RESULTS

Among 131 patients, 30 (22.9%) karyotypes were normal and the remaining 101 (77.1%) had abnormal karyotypes with numerical and/or structural abnormalities. Among patients with numerical abnormalities, the most frequent karyotypes were hyperdiploidy with 51-65 chromosomes (30 patients) and hyperdiploidy with 47-50 chromosomes (18 patients). Among recurrent, non-random, and primary structural abnormalities, the most frequent was t(9;22), followed by t(1;19). Aberrations involving band 11q23 were not detected, and only one of two patients with L3 had the t(8;14). Of the secondary non-random abnormalities, dup(1q), del(6q), and i(7)(q10) were found.

CONCLUSIONS

The frequency and type of chromosomal abnormalities found was comparable to those reported in the literature with similar methodology and pediatric populations; however, the number of cases analyzed should be increased to create a database of Mexican children with ALL, and several patients require molecular analysis to identify chromosomal abnormalities not detected through conventional cytogenetic studies.

Fifteen cases of t(1;19)(q23;p13.3) identified in an Australian series of 122 children and 80 adults with acute lymphoblastic leukemia

The t(1;19)(q23;p13) has been reported in up to 6% of cytogenetically abnormal cases of acute lymphoblastic leukaemia (ALL), associated with a pre-B-ALL phenotype. In the 5-year period 1995-1999, we detected t(1;19) in 13 children and 2 adults with newly diagnosed ALL. This represented 10% of pediatric and 2.5% of adult diagnostic ALL samples successfully cultured in one center during this time. There were 9 males and 6 females. The mean age at diagnosis for the 13 children was 6.5 years (range 1.5 to 14 years) and the 2 adults were aged 42 and 45 years. The unbalanced t(1;19) occurred in 7 of 13 children (54%), contrary to the reported excess of unbalanced translocations at 75%; both adults had the unbalanced translocation. At diagnosis, the t(1;19) was the sole abnormality in 4 patients (26%), and in the remainder (74%) was part of a complex karyotype, which included i(7q) (2 patients), hyperdiploidy (2 patients) and del(6q) (2 patients). Correlation of karyotype with white cell, blast and platelet counts, cell surface markers, initial response to chemotherapy and short-term outcome showed no difference between the balanced and unbalanced forms of the translocation in children or whether t(1;19) was present as the sole abnormality or part of a complex karyotype.

Prognostic value of tumoral ploidy in a series of spanish patients with acute lymphoblastic leukemia

The prognostic value of tumoral ploidy and its relation with nonrandom chromosome alterations were analyzed in 89 cases of acute lymphoblastic leukemia. Ploidy is associated with the number of nonrandom chromosome alterations and survival. The pseudodiploid and hypodiploid groups had a high incidence of nonrandom alterations and poor survival while the diploid and high hyperdiploid groups had a lower incidence of nonrandom alterations and longer survivals. The patients in the low hyperdiploid group with random alterations received the same treatment as the diploid and high hyperdiploid groups but had poor survivals. Our analysis confirms that ploidy is a very important prognostic factor and suggests that patients with low hyperdiploidy should receive intensive therapies similar to those of patients in the groups with a high number of nonrandom alterations.

6q Deletions in Acute Lymphoblastic Leukemia and Non-Hodgkin's Lymphomas

Deletions on the long arm of chromosome 6 are frequently found in acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphomas (NHL). We have used polymerase chain reaction analysis to study loss of heterozygosity of 16 microsatellite markers on chromosome 6 in 74 ALL and 54 NHL patients. Our results show that deletions of 6q in ALL are more frequent than what has been reported in previous studies, occurring in at least 32% of the patients. The corresponding figure for NHL patients is 7%. Our results define a region of minimal deletion in ALL of less than 500 kb between markers D6S1709 and D6S434. The common region of deletion in NHL is located telomeric of this region. Thus, two different tumor suppressor genes on chromosome 6q seem to be relevant for the development of lymphoid malignancies.

6q Deletions in Acute Lymphoblastic Leukemia and Non-Hodgkin's Lymphomas

Deletions on the long arm of chromosome 6 are frequently found in acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphomas (NHL). We have used polymerase chain reaction analysis to study loss of heterozygosity of 16 microsatellite markers on chromosome 6 in 74 ALL and 54 NHL patients. Our results show that deletions of 6q in ALL are more frequent than what has been reported in previous studies, occurring in at least 32% of the patients. The corresponding figure for NHL patients is 7%. Our results define a region of minimal deletion in ALL of less than 500 kb between markers D6S1709 and D6S434. The common region of deletion in NHL is located telomeric of this region. Thus, two different tumor suppressor genes on chromosome 6q seem to be relevant for the development of lymphoid malignancies.