Comparison of Diagnostic Yield of a FISH Panel Against Conventional Cytogenetic Studies for Hematological Malignancies: A South Indian Referral Laboratory Analysis of 201 Cases

Abstract

<br /> <strong><span style="font-size: small;">Objectives: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Genetic markers are crucial fort diagnostic and prognostic investigation of hematological malignancies </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">(HM). The conventional cytogenetic study (CCS) has been the gold standard for more than five decades. However, FISH (Fluorescence in Situ Hybridization) testing has become a popular modality owing to its targeted approach and the ability to detect abnormalities in non-mitotic cells. We here aimed to compare the diagnostic yields of a FISH </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">panel against CCS in HMs. </span></span><strong><span style="font-size: small;">Methods: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Samples of bone marrow and peripheral blood for a total of 201 HMs were </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">tested for specific gene rearrangements using multi-target FISH and the results were compared with those from CCS. </span></span><strong><span style="font-size: small;">Results: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Exhibited a greater diagnostic yield with a positive result in 39.8% of the cases, as compared to 17.9% of cases </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">detected by CCS. Cases of chronic lymphocytic leukaemia (CLL) benefited the most by FISH testing, which identified chromosomal aberrations beyond the capacity of CCS. FISH was least beneficial in myelodysplastic syndrome (MDS) </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">where the highest concordance with CCS was exhibited. Acute lymphocytic leukaemia (ALL) demonstrated greater </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">benefit with CCS. In addition, we found the following abnormalities to be most prevalent in HMs by FISH panel testing: RUNX1 (21q22) amplification in ALL, deletion of D13S319/LAMP1 (13q14) in CLL, CKS1B (1q21) amplification in multiple myeloma and deletion of EGR1/RPS14 (5q31/5q32) in MDS, consistent with the literature. </span></span><strong><span style="font-size: small;">Conclusions: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">In conclusion, FISH was found to be advantageous in only a subset of HMs and cannot completely replace CCS. </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Utilization of the two modalities in conjunction or independently should depend on the indicated HM for an optimal approach to detecting chromosomal aberrations. </span></span>