Two different Philadelphia chromosomes in a cell line from an AML-M0 patient.


A second Philadelphia (Ph) chromosome is one of the most common nonrandom secondary chromosome changes in leukemias with 9;22 translocations. It has been suggested, and observed in two studies of masked t(9;22), that the second Ph chromosome is an exact duplication of the entire derivative chromosome 22. In a cytogenetic study of bone marrow cells from an acute myelogenous leukemia patient, a cell line carrying two different Ph chromosomes evidenced by a chromosome 22 centromeric heteromorphism was found. From this observation arose the question whether the second der(22) was a true Ph chromosome or whether it was a deleted chromosome derived from the normal chromosome 22 that did not contain the bcr-abl rearrangement. A fluorescent in situ hybridization (FISH) study with the t(9;22) probe revealed two bcr-abl positive signals on 60 of 100 interphase nuclei. The second Ph could have resulted from a mitotic crossing over; or, analogously to late-appearing Philadelphia chromosomes, it may be derived from a new chromatid translocation between the chromosomes 9 and 22 not involved in the initial t(9;22).

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@article{Garca1997TwoDP, title={Two different Philadelphia chromosomes in a cell line from an AML-M0 patient.}, author={Juan Ram{\'o}n Gonz{\'a}lez Garc{\'i}a and O M Garc{\'e}s Ru{\'i}z and Jose Luis Delgado Lamas and Mar{\'i}a de Lourdes Ram{\'i}rez-Dueńas}, journal={Cancer genetics and cytogenetics}, year={1997}, volume={98 2}, pages={111-4} }