Cryptic aberrations may allow more accurate prognostic classification of patients with myelodysplastic syndromes and clonal evolution.

The karyotype of bone-marrow cells at the time of diagnosis is one of the most important prognostic factors in patients with myelodysplastic syndromes (MDS). In some cases, the acquisition of additional genetic aberrations (clonal evolution [CE]) associated with clinical progression may occur during the disease. We analyzed a cohort of 469 MDS patients using a combination of molecular cytogenomic methods to identify cryptic aberrations and to assess their potential role in CE. We confirmed CE in 36 (8%) patients. The analysis of bone-marrow samples with a combination of cytogenomic methods at diagnosis and after CE identified 214 chromosomal aberrations. The early genetic changes in the diagnostic samples were frequently MDS specific (17 MDS-specific/57 early changes). Most progression-related aberrations identified after CE were not MDS specific (131 non-MDS-specific/155 progression-related changes). Copy number neutral loss of heterozygosity (CN-LOH) was detected in 19% of patients. MDS-specific CN-LOH (4q, 17p) was identified in three patients, and probably pathogenic homozygous mutations were found in TET2 (4q24) and TP53 (17p13.1) genes. We observed a statistically significant difference in overall survival (OS) between the groups of patients divided according to their diagnostic cytogenomic findings, with worse OS in the group with complex karyotypes (P = .021). A combination of cytogenomic methods allowed us to detect many cryptic genomic changes and identify genes and genomic regions that may represent therapeutic targets in patients with progressive MDS.

Cytogenomic Profiling of Chronic Lymphocytic Leukaemia Patients Using DNA Microarray

@#Introduction: Chronic lymphocytic leukaemia (CLL) is the most frequent adult leukaemia in the Western world. The clinical presentation varies greatly, from very indolent cases to those with aggressive and fast advancing disease. This variation has significant implications for clinical approaches, therapeutic tactics, and, ultimately, survival durations from diagnosis. Acquired chromosomal aberrations play a key role in CLL aetiology. Due to difficulty to obtain abnormal metaphases for analysis, few methods such as fluorescence in-situ hybridization (FISH) and multiplex ligation-dependent probe assay (MLPA) were employed to detect chromosomal aberration however the methods are limited to specific locus only. Thus, this study is aimed to detect the chromosomal aberrations using DNA microarray platform. Methods: In this retrospective study, DNA archive obtained from 7 CLL patients which collected at diagnosis and subjected to Affymetrix CytoScan® 750K single nucleotide polymorphism (SNP) array following the manufacture procedure. The raw data obtained were analysed using the Chromosome Analysis Suite (ChAS) software (Affymetrix) using annotations of genome version GRCh38 (hg38). Result: Out of 7 patients, 4 of them showing deletion of 13q while 3 of them showing deletion of 14q in various region . Some of the deleted loci were too small (0.42-0.6Mb) to be detected by conventional cytogenetic analysis (CCA). There was also the presence of additional chromosomal aberrations that could be missed by CCA, FISH, or MLPA due to cryptic deletion or duplication that was as small as 0.4MB in size. Conclusion: The present study showed that low resolution chromosomal aberration was able to be detected using DNA microarray platform in comparison to CCA, FISH and MLPA.