Conventional chromosome banding (CCB) analyses of bone marrow (bm) metaphases represent the gold standard of cytogenetic diagnostics in myelodysplastic syndromes (MDS), but they are not suitable for frequent follow-up analyses. Most aberrations can also be detected by fluorescence in situ hybridisation (FISH), and they are provable in CD34+ cells from peripheral blood (pb). In our prospective multicenter German diagnostic study “Screening and genetic monitoring of patients with MDS under different treatment modalities by cytogenetic analyses of circulating CD34+cells” (ClinicalTrails.gov NCT01355913) we followed MDS pts by sequential FISH analyses.
CD34+ pb cells were enriched by immunomagnetic cell sorting (MACS®) and analysed by FISH using a “Superpanel” (D7/CEP7, EGR1, CEP8, CEP XY, D20, TP53, IGH/BCL2, TEL/AML1, RB1, MLL, 1p36/1q25, CSF1R, all Abbott® Products) at initial screening, every 12 months during follow-up and in case of suspected disease progression and a “Standardpanel” (EGR1, D7/CEP7, CEP8, TP53, D20, TEL/AML1, CEP XY, plus -if necessary- another informative probe) every 2 months in the 1st and every 3 months in the 2nd and 3rd year. If bm aspirate was available, additional CCB and FISH analysis of CD34+ and native bm cells were performed. Cut-off values for each FISH probe were evaluated in our lab. Cytogenetics, bm morphology, clinical course and therapies were documented in a database. All pts gave their written informed consent. The study was approved by all local ethic committees.
After 3 years of study time, 361 patients (25 AZALE (University of Dresden), 110 LEMON5 (University of Duesseldorf), 226 CD34+FISH) have been included in the study, resulting in a total number of 19,516 FISH analyses: Median age, gender distribution and MDS subtypes were typical for the disease, median follow-up at the time of analysis was 8.2 (1–36) months. Chromosomal aberrations could be detected by FISH of CD34+ pb cells in 71.5% of pts (55% of CD34+FISH-cohort, 99% of LEMON5-trial pts, 100% of AZALE-trial pts). FISH and CCB were highly correlated: p<0.01 for CD34+ pb FISH vs CCB and p<0.01 for CD34+ bm vs CCB. The clone sizes were significantly larger in CD34+ cells compared to native pb (p<0.01).
Our interim results demonstrate that FISH analysis of circulating CD34+ pb cells provides relevant cytogenetic informations. It is a reliable novel method for screening and cytogenetic monitoring of MDS pts during the course of disease and under different therapies, and helps in cases where a bm biopsy is not possible or not successful.
Braulke:Celgene: This study was supported by Celgene. Other. Götze:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bug:Celgene: Honoraria, travel support, advisory board Other; Novartis: Honoraria, travel support, advisory board, travel support, advisory board Other; Boehringer Ingelheim: Honoraria, travel support, advisory board, travel support, advisory board Other. Schafhausen:Novartis: Honoraria, travel support Other; BMS: Honoraria, travel support, travel support Other; Roche: Honoraria, travel support, travel support Other; Celgene: Honoraria, travel support, travel support Other; Alexion: Honoraria, travel support Other. Haase:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.
Asterisk with author names denotes non-ASH members.