The MYH11/CBFB DNA-FISH Probe is designed to detect the pericentric inversion of chromosome 16 (inv(16)(p13q22) and t(16;16)(p13;q22)  involving the MYH11 gene on 16p13 and the CBFB gene on 16q22 using fluorescence in situ hybridization (FISH).  The rearrangement of the MYH11 and CBFB gene results in a fusion of both genes.  The inv(16) abnormality is found in ~5 – 8% of all of de novo acute myeloid leukemia (AML) cases and is associated with AML-M4eo subtype (based on FAB classification).^[1,2]  Inv(16) and t(16;16) has also been observed in therapy related myelodysplastic syndrome (t-MDS) cases and in eosinophilic blast crisis of chronic myelogenous leukemia (CML) cases.^[2]  Whether alone or as part of a complex patient karyotype, inv(16) is indicative of a good prognosis in AML cases.^[3]