Myelodysplastic syndrome with Philadelphia-like chromosome without bcr rearrangement

The case of a 62-year-old Japanese male with a myelodysplastic syndrome and a Philadelphia (Ph)-like chromosome, which probably involved bands 11q23 and 22q11, is presented. Cytogenetic analysis of bone marrow cells revealed a Ph chromosome as well as -5, -7, +8, +11, -16, and an extra Ph. Some of the cells had 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 chromosome in this case differs from that of Ph-positive chronic myelogenous leukemia, and the present case suggests that we should retain the term of "Ph-like chromosome" in such cases.