Whole Chromosome Painting and Multiplex Fluorescence In Situ Hybridization in Detecting Complex Chromosomal Aberrations in Myelodysplastic Syndromes.

Abstract Objective To explore the value of the technique of whole chromosome painting (WCP) and multiplex fluorescence in situ hybridization (M-FISH) in the detection of complex chromosomal aberrations (CCAs) of myelodysplastic syndromes (MDS). Methods M-FISH was used in seven MDS patients with CCAs detected by R-banding technique to refine CCAs, and to identify cryptic translocations and characterization of marker chromosomes. Dual-color WCP procedures were further performed in 7 cases to confirm some rearrangements detected by M-FISH. Results In all cases, M-FISH confirmed all results of R-banding.The composition and origin of 6 kinds of marker chromosomes, 9 kinds of chromosomes with additional material undetermined and 5 kinds of derivative chromosomes undefined by CC were defined after M-FISH analysis; 4 kinds of cryptic translocations overlooked by CC were found on derivative chromosomes and previously normal appearing chromosomes. In addition, M-FISH revealed some nonrandom aberrations: aberrations involving chromosome 17 (5/7) and -5/5q- (4/7) were the two most frequent aberrations. Fluorescence flaring is a main factor leading to misinterpretations. Some misclassified and missed chromosomal aberrations by M-FISH were corrected by WCP. Conclusions M-FISH is a powerful molecular cytogenetic tool in clarification of CCAs. Complementary WCP helped us identify misclassified and missed chromosomal aberrations by M-FISH. CC in combination with molecular cytogenetic techniques M-FISH and WCP can unravel complex chromosomal aberrations more precisely.