Pilot study of the feasibility of fluorescence in SITU hybridisation (FISH) analysis on bone marrow trephine imprints

Abstract

FISH analysis of cultured fixed cell suspensions from marrow aspirate is routinely used to diagnose and risk stratify haematological neoplasms. Occasionally, the aspirate is hypoparticulate due to fibrosis, extensive infiltration or operator error. Accordingly, the utility of FISH is reduced due to an absence of neoplastic cells. Although FISH can be performed on formalin fixed, paraffin embedded tissue, e.g., trephines, the success of this technique is variable, subject to certain technical limitations and not available in all laboratories. FISH has been successfully applied to other tissue imprints but its specific application to trephine imprints is not yet widely reported. We aimed to assess the feasibility of FISH analysis on imprints obtained from diagnostic marrow trephines. From our database, five samples positive by FISH for abnormalities with diagnostic, therapeutic or prognostic implications were identified [one each of Ph + ALL, AML t(8;21), APL, CMML inv3 and mantle cell lymphoma]. FISH was performed on stored air-dried imprints of the trephines: in all cases, yielding adequate/comparable signals to that of the cell suspension. These findings suggest FISH on trephine imprints is feasible, may be helpful if the aspirate is hypoparticulate, and that prospective study of its yield in that situation is warranted.