Additional translocation (9;12)(p13;q24.1) in newly diagnosed chronic myeloid leukemia: complete cytogenetic...

We report the case of a patient with chronic phase CML who exhibited, in the same cells, beside the Philadelphia chromosome, an additional translocation between the other chromosome 9 and one of the chromosomes 12 [t(9;12)(p13;q24.1)]. Complete cytogenetic remission with disappearance of both karyotypic abnormalities was achieved after 18 months treatment with low dose (1.4 x 10(6) U/m2/day) recombinant alpha-interferon and has been sustained with maintenance therapy for 68+ months (actual follow-up). Clonality at diagnosis and recovery of polyclonal hematopoiesis in complete cytogenetic remission were demonstrated using the polymorphism at the human androgen receptor gene (Humara) locus on chromosome X. The role of the additional translocation in the response to low dose alpha-interferon therapy remains hypothetical.