Two-colour FISH detection of the inv(16) in interphase nuclei of patients with acute myeloid leukaemia

The inv(16)(p13q22) and t(16:16)(p13;q22) in acute myeloid leukaemia are as sociated with a relatively good prognosis but are difficult to detect using classic cytogenetics. We have designed a two-colour fluorescence in situ h ybridization approach that uses two DNA probes that map close to and on eit her side of the inv(16) p-arm breakpoint region, This new strategy clearly detected the inv(16)(p13q22)/t(16;16)(p13:q22) on both metaphase chromosome s and in interphase nuclei, even when they are of poor quality, This proced ure also detected the inv(16) in cases with an additional deletion of seque nces proximal to the 16p-arm breakpoint which is present in 20% of all case s.