Nonclassical Philadelphia-positive FISH signal patterns in CML and seven cases with variant Philadelphia

Because variant translocations are extremely rare and involve many different chromosomal breaks, a large number of cases are needed to clearly understand their prognostic implications. Due to the limitations of conventional cytogenetic analyses, it should be considered in patient follow-up that nonclassical FISH signal patterns indicating deletions and/or variant translocations may cause a delay in obtaining a complete cytogenetic response at the 6th month.