Quantity of clonal cells detected by conventional cytogenetic analysis correlates with bone marrow blasts and survival in myelodysplastic syndromes

Monitoring of the Clonal Fraction by Fluorescence In Situ Hybridization in Myelodysplastic Syndrome: Comparison With International Working Group Treatment Response Criteria

CONTEXT

-At the initial diagnosis of myelodysplastic syndrome (MDS) and/or during follow-up, the evaluation of chromosomal abnormalities is based on standard G-banding, whereas the utility of fluorescence in situ hybridization (FISH) is still debated.

OBJECTIVES

-To investigate whether interphase fluorescence in situ hybridization (iFISH) clone size at initial diagnosis of MDS is correlated with survival and whether changes in clonal fraction by iFISH are concordant with the MDS International Working Group response criteria during follow-up.

DESIGN

-A tailored FISH panel (-5/5q-, -7/7q-, +8, -20/20q-, and +1/1q+), based on reported cytogenetic changes in Korean patients with MDS, was performed in 81 patients with MDS at initial diagnosis and in 28 patients during follow-up.

RESULTS

-During follow-up, absolute increases in the clone size by iFISH by 20% or more, with relative increases of 50% or more, compared with previous specimens, were associated with transformation to acute myeloid leukemia (P = .001 and P = .002, respectively). Of the 28 patients with abnormal iFISH results, 7 (25%) showed discordance between iFISH and MDS International Working Group responses. Concordance between clone size by G-banding and iFISH was higher in the refractory cytopenia with unilineage dysplasia/refractory cytopenia with multilineage dysplasia group during follow-up, whereas the group with refractory anemia with excess blasts showed higher correlation at initial diagnosis.

CONCLUSIONS

-We conclude that iFISH can provide additional prognostic information and can predict the response to therapy in MDS.