An unusual T-cell childhood acute lymphoblastic leukemia harboring a yet unreported near-tetraploid karyotype

Frequency of chromosomal abnormalities in Pakistani adults with acute lymphoblastic leukemia

BACKGROUND

The difference in prognosis of adult and childhood acute lymphoblastic leukemia (ALL) can be attributed largely to variation in cytogenetic abnormalities with age groups. Cytogenetic analysis in acute leukemia is now routinely used to assist patient management, particularly in terms of diagnosis, disease monitoring, prognosis and risk stratification. Knowing about cytogenetic profile at the time of diagnosis is important in order to take critical decisions in management of the patients.

AIM AND OBJECTIVES

To determine the frequency of cytogenetic abnormalities in Pakistani adult patients with ALL in order to have insights regarding behavior of the disease.

MATERIALS AND METHODS

A retrospective analysis of all the cases of ALL (≥15years old) diagnosed at Aga Khan University from January 2006 to June 2014 was performed. Phenotype (B/T lineage) was confirmed in all cases by flow cytometry. Cytogenetic analysis was made for all cases using the trypsin-Giemsa banding technique. Karyotypes were interpreted using the International System for Human Cytogenetic Nomenclature (ISCN) criteria.

RESULTS

A total of 166 patients were diagnosed as ALL during the study period, of which 151 samples successfully yielded metaphase chromosomes. The male to female ratio was 3.4:1. The majority (n=120, 72.3%) had a B-cell phenotype. A normal karyotype was present in 51% (n=77) of the cases whereas 49% (n=74) had an abnormal karyotype. Of the abnormal cases, 10% showed Philadelphia chromosome; t(9;22)(q34;q11.2). Other poor prognostic cytogenetic subgroups were t(4;11)(q21;q23), hypodiploidy (35-45 chromosomes) and complex karyotype. Hyperdiploidy (47-57 chromosomes) occurred in 6.6%; all of whom were younger than 30 years.

CONCLUSIONS

This study showed a relatively low prevalence of Philadelphia chromosome in Pakistani adults with ALL with an increase in frequency with age (p=0.003). The cumulative prevalence of Philadelphia- negative poor cytogenetic aberrations in different age groups was not significant (p=0.6).

Banding cytogenetic analysis in pediatric patients with acute lymphoblastic leukemia (ALL) in a Brazilian population

BACKGROUND

Cytogenetic studies in Brazilian population about childhood acute lymphoblastic leukemia (ALL), the most common childhood malignancy, are scarce. Moreover, Brazilian race is very heterogeneous and is made by the confluence of people of several different origins, from the original Native Brazilians, with the influx of Portuguese colonizers, Black African slaves, and recent European, Arab and Japanese immigration. The purpose of this prospective, multicentric study was to assess the sociodemographic, clinic and cytogenetic characteristics of the children treated for ALL in the Northeast region of Brazil.

RESULTS

This study includes thirty patients between 4 months and 17 years old treated for ALL from January 1st, 2009 to November 30th, 2010. Cytogenetic analysis showed that in nineteen out of thirty patients (64%) presented some chromosome abnormalities, in which 53% corresponds to numerical abnormalities, 21% structural and numerical abnormalities, and 26% only structural changes. Moreover, seven patients presented complexes karyotype not yet described in the literature. Taken together these results show the importance of the cytogenetic analysis in ALL pediatric patients and illustrates that the studied population presented unexpected complexes karyotypes which were correlated to poor outcome.

CONCLUSION

The results demonstrate the importance of banding cytogenetics for ALL diagnosis despite the use of most modern techniques such as FISH and aCGH, and provide reliable insight into the ALL in Brazil.

Chromosome anomalies in bone marrow as primary cause of aplastic or hypoplastic conditions and peripheral cytopenia: disorders due to secondary impairment of RUNX1 and MPL genes

Background

Chromosome changes in the bone marrow (BM) of patients with persistent cytopenia are often considered diagnostic for a myelodysplastic syndrome (MDS). Comprehensive cytogenetic evaluations may give evidence of the real pathogenetic role of these changes in cases with cytopenia without morphological signs of MDS.

Results

Chromosome anomalies were found in the BM of three patients, without any morphological evidence of MDS: 1) an acquired complex rearrangement of chromosome 21 in a boy with severe aplastic anaemia (SAA); the rearrangement caused the loss of exons 2–8 of the RUNX1 gene with subsequent hypoexpression. 2) a constitutional complex rearrangement of chromosome 21 in a girl with congenital thrombocytopenia; the rearrangement led to RUNX1 disruption and hypoexpression. 3) an acquired paracentric inversion of chromosome 1, in which two regions at the breakpoints were shown to be lost, in a boy with aplastic anaemia; the MPL gene, localized in chromosome 1 short arms was not mutated neither disrupted, but its expression was severely reduced: we postulate that the aplastic anaemia was due to position effects acting both in cis and in trans, and causing Congenital Amegakaryocytic Thrombocytopenia (CAMT).

Conclusions

A clonal anomaly in BM does not imply per se a diagnosis of MDS: a subgroup of BM hypoplastic disorders is directly due to chromosome structural anomalies with effects on specific genes, as was the case of RUNX1 and MPL in the patients here reported with diagnosis of SAA, thrombocytopenia, and CAMT. The anomaly may be either acquired or constitutional, and it may act by deletion/disruption of the gene, or by position effects. Full cytogenetic investigations, including a-CGH, should always be part of the diagnostic evaluation of patients with BM aplasia/hypoplasia and peripheral cytopenias.