Molecular and cytogenetic characterization of myelodysplastic syndromes in cell-free DNA

Molecular and cytogenetic studies are essential for diagnosis and prognosis in patients with myelodysplastic syndromes (MDSs). Cell-free DNA (cfDNA) analysis has been reported to be a reliable noninvasive approach for detecting molecular abnormalities in MDS; however, there is limited information about cytogenetic alterations and monitoring in cfDNA. We assessed the molecular and cytogenetic profile of a cohort of 70 patients with MDS by next-generation sequencing (NGS) of cfDNA and compared the results to sequencing of paired bone marrow (BM) DNA. Sequencing of BM DNA and cfDNA showed a comparable mutational profile (92.1% concordance), and variant allele frequencies (VAFs) strongly correlated between both sample types. Of note, SF3B1 mutations were detected with significantly higher VAFs in cfDNA than in BM DNA. NGS and microarrays were highly concordant in detecting chromosomal alterations although with lower sensitivity than karyotype and fluorescence in situ hybridization. Nevertheless, all cytogenetic aberrations detected by NGS in BM DNA were also detected in cfDNA. In addition, we monitored molecular and cytogenetic alterations and observed an excellent correlation between the VAFs of mutations in BM DNA and cfDNA across multiple matched time points. A decrease in the cfDNA VAFs was detected in patients responding to therapy, but not in nonresponding patients. Of note, cfDNA analysis also showed cytogenetic evolution in 2 nonresponsive cases. In summary, although further studies with larger cohorts are needed, our results support the analysis of cfDNA as a promising strategy for performing molecular characterization, detection of chromosomal aberrations and monitoring of patients with MDS.