Complexity of an apparently simple variant Ph translocation in chronic myeloid leukemia

A patient with chronic myeloid leukemia (CML) presented with an apparently simple Ph translocation t(19;22)(q13;q11). In-situ hybridization revealed movement of the c-abl oncogene from a cytogenetically normal chromosome 9 to the Ph. Bcr-3' and c-sis probes hybridized to distal 1p and not to the 19q+ chromosome as expected from the cytogenetic findings. We concluded that this patient had a complex translocation involving four chromosomes: t(1;9;19;22)(p36;q34;q13;q11).