Identification of the breakpoints at 1p36.2 and 3p21.3 in an AML(M3) patient who had t(1;3)(p36.2;p21.3) at the third relapse

Recently, we reported that a recurrent translocation, t(1;3)(p36;p21) is closely associated with prior chemotherapy including alkylating agents, assessing eight patients with various hematologic malignancies (Genes, Chromosomes and Cancer 34:186- 192), 2002). Furthermore, we delineated the 1p36 breakpoint in two patients lying between RP11-BAC47P3 and RP5-PAC963K15 at 1p36.3 with a small deletion near the breakpoint. In one of them, we also found deletion at 3p21.3 with cosNRL9 probe, which is included in a 370-kb lung cancer homologous deletion region. However, due to scantiness of the patient materials at that time, we could not determine the precise breakpoint at 1p36 or 3p21 in any of the patients. In this report, we identified the 1p36 and 3p21 breakpoints of an AML (M3) patient who is included in the previous patient series. The patient showed t(1;3)(p36;p21) together with t(15;17) at the third relapse. With FISH using BAC/PAC probes, we determined the 1p36 breakpoint within RP11-295B1 at 1p36.2 and the 3p21 breakpoint between RP11-3B7 and RP11-901L6 at 3p21.3. There was no deletion around the two breakpoints in this patient. To the best of our knowledge, this is the first report that has identified the precise breakpoint of t(1;3)(p36;p21) transiocation. It is obvious that the 1p36.2 and 3p21.3 breakpoints of this patient are different from those of the previous patients, suggesting that the genes and the molecular event is different from those of the previous patients. The patients with t(1;3)(p36;p21) should be subclassified according to the precise breakpoints or the genes involved.