Fluorescence in Situ Hybridization (FISH) Utility for Risk Score Assessment in Patients With MDS With Normal Metaphase Karyotype

Around 50% to 60% of patients with myelodysplastic syndromes have normal cytogenetics by metaphase karyotype. Here we report the yield of myelodysplastic syndromes fluorescence in situ hybridization panel detecting cytogenetic abnormalities in these patients and its impact on risk stratification. Background: Cytogenetic profile is an essential parameter in myelodysplastic syndromes (MDS) risk stratification by both International Prognostic Symptom Score (IPSS) and Revised (R)-IPSS. Almost one-half of patients with MDS have normal cytogenetics by metaphase karyotype. Here we report the yield of MDS fluorescence in situ hybridization (FISH) panel detecting cytogenetic abnormalities in these patients and its impact on risk stratification. Patients and Methods: Among patients with normal metaphase karyotype, we assessed those patients who had cytogenetic abnormalities detected by an MDS FISH panel, which included probes for del (5), del (7), del (20), trisomy 8, and del (17p). Risk stratification was calculated by both IPSS and R-IPSS. Results: Of 1600 patients with MDS with normal metaphase karyotype, 53 (3%) patients had cytogenetic abnormality detected by MDS FISH panel. Integrating the MDS FISH panel cytogenetics (IPSS + FISH restaging) resulted in upstaging the score, where 53% of low-risk IPSS were upstaged to intermediate (int)-1, 56% of int-1 were upstaged to int-2, and 78% of int-2 were upstaged to high risk. Based on the R-IPSS, 61% of very low-risk patients, all low-risk patients, 92% of intermediate-risk patients, and 50% of high-risk patients with FISH abnormalities were upstaged, respectively. Conclusion: The yield of MDS FISH panel detecting cytogenetic abnormalities in patients with normal karyotype by G-banding is low and may not warrant ordering the panel in all patients. Among the 3% of patients with normal karyotype who had cytogenetic abnormality detected by FISH, the risk score assignment by IPSS and R-IPSS was upstaged. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

The yield of detecting cytogenetic abnormalities in patients with normal karyotype by using a myelodysplastic syndromes fluorescence in situ hybridization (FISH) panel is low, but it significantly impacts risk stratification.