Molecular Implications of Ph (+) Myelodysplastic Syndrome

We report a case of 62-year-old Japanese male with a myelodysplastic syndrome (MDS) with a Philadelphia (Ph) chromosome. Cytogenetic analysis revealed the bone marrow cells to contain a Ph chromosome due to t(?;11;22) (?;q11;q11), as well as −5, −7, +8, −12 and an extra Ph, in addition to cells with a normal karyotype. Molecular analysis using breakpoint cluster region probes (5′ bcr and 3′ bcr) did not detect a rearrangement within the bcr DNA sequences, indicating that the breakpoint at 22q11 occurred outside the bcr. Furthermore, the bone marrow cells from this patient did not express an 8.5 kb c-abl mRNA. Thus, the Ph translocation in this case differs from that of Ph-positive chronic myelogenous leukemia.