Application of fluorescence in situ hybridization technique to verify the clonalities of non-clonal cytogenetic abnormalities identified in Myelodysplastic syndrome

Abstract

To assess the value of fluorescence in situ hybridization (FISH) technique for the verification of the clonalities of non-clonal cytogenetic abnormalities (n-CCA) identified by conventional chromosome banding analysis (CBA) in patients with Myelodysplastic syndrome (MDS). Clinical data and results of karyotyping and FISH assays for 91 patients of MDS with n-CCA identified by CBA were retrospectively analyzed. In total 94 non-clonal +8, 5q-, -7/7q- or 20q- were detected by CBA, among which 43 (45.7%) were verified to be clonal abnormalities by FISH. The detection rates for +8, 5q-, -7/7q- and 20q- by FISH were 47.6% (30/63), 25% (2/8), 41.7% (5/12), 40% (2/5) and 66.7% (4/6), respectively, with the positive cells accounting for 4% to 90% of all counted cells, with a median value of 7%. The 91 patients were divided into three groups including ≥ 20, 10 ~< 20 and < 10 based on the numbers of metaphase cells in CBA, and the detection rates by FISH for the three groups were 43.7% (31/71), 33.3% (3/9) and 63.6% (7/11), respectively, which showed no statistically difference (P > 0.05). Continuous CBA and FISH surveys were conducted for 26 patients who received supportive treatment, and the results revealed that 91.7% (11/12) of FISH-verified positive abnormalities had persisted, whereas 92.9% (13/14) of the n-CCA verified as negative by FISH was transient. Nearly half of the CBA identified n-CCA have been verified as clonal aberrations by FISH, and the FISH detection rate showed no correlation with the number of metaphase cells. FISH test is strongly recommended for verifying the clonalities of n-CCA detected by CBA, and continuous cytogenetic survey of the patients with MDS is necessary.