Philadelphia chromosome positive myelodysplastic syndrome and acute myeloid leukemia-retrospective study and review of literature.

We conducted a retrospective study to define the significance of Philadelphia chromosome (Ph) in myelodysplastic syndrome and acute leukemia in the adults at this institution and the literature was reviewed. One hundred forty-eight cases of t(9;22)(q34;q11) were identified for the period September 1993 through August 2001. The presentation of 124 cases (84%) was that of typical CML in chronic phase. Nineteen cases (13%) presented as de novo ALL, two cases (1%) presented as de novo AML and three cases (2%) presented as myelodysplastic syndrome (MDS). The estimated incidences of t(9;22)(q34;q11) in ALL and AML are 21 and 0.6%, respectively. Ph+ AMLs are increasingly being reported with either M-BCR or m-BCR gene rearrangements, similar to those found with Ph+ ALL lending support to the notion that Ph+ AMLs are distinct entities and not merely blastic phases of undiagnosed CML. This is further supported by the existence of Ph+ MDS cases.