Historical communication: Philadelphia-positive chronic myelogenous leukemia followed for 27 years.

The patient we studied was diagnosed as having chronic myelogenous leukemia (CML), possibly radiation-induced, in 1960 at age 9, and a Philadelphia chromosome was first demonstrated in the neoplastic cells in 1961. Her subsequent clinical course has been cyclic, requiring periodic therapy, but there has been no karyotypic progression. A study in 1987 continued to show the typical t(9;22) translocation as the only cytogenetic alteration, and concurrent molecular investigation of the neoplastic cells revealed a breakpoint cluster region rearrangement, also typical of CML. The chromosomal and molecular data provide no obvious explanation for her remarkably prolonged survival.