The MLL probe, labelled in green, covers a 200kb region including the MLL (KMT2A) gene. The MLLT4 probe, labelled in red, consists of two clones (187kb and 136kb) that flank the MLLT4 gene.
Translocations involving chromosome 11q23 frequently occur in both acute myeloid leukaemia (AML) and acute lymphoblastic leukaemia (ALL). In most cases, the MLL gene is involved but translocation partners are extremely variable, with 79 direct translocation partners having been molecularly characterised so far.
The most common MLL rearrangement in both AML and ALL involves fusion of the MLL and AFF1 (AF4) genes via a t(4;11)(q21;q23) translocation. Three of the other more common translocations involve the MLLT3 (AF9) gene on chromosome 9, the MLLT1 (ENL) gene on chromosome 19 or the MLLT4 (AF6) gene on chromosome 6:
We now have a range of Research Use Only (RUO) Translocation, Dual Fusion probes to allow specific detection of these MLL rearrangements.
I first came across CytoCell FISH probes in a previous lab I worked in and I was struck by the quality of the products. Since this time, I have been recommending and introducing CytoCell probes across all application areas — now they are the primary FISH probes used in our lab. They have an excellent range of products and their ready-to-use reagent format saves considerable time.
Medical Technologist, University of Arizona Health Network, USA