Translocation (1;7)(p11;p11): a new myeloproliferative hematologic entity.

Four cases with myeloproliferative syndromes or acute nonlymphocytic leukemia associated with t(1;7)(p11;p11) are presented. In each case, as in all cases published in the literature, the karyotypes of the affected cells contained two normal chromosomes #1, but only one chromosome #7, with the result that the basic karyotype was 46, -7, +t(1;7). This chromosome change is not geographically restricted, and appears to characterize a group of patients with myeloproliferative disorders and acute nonlymphocytic leukemia, including myeloproliferative syndromes, in whom exposure to previous chemotherapy, x-rays, or drugs is in the background history. The t(1;7) in secondary leukemia and myeloproliferative syndromes serves to duplicate the long arm of a chromosome #1 and to rescue the short arm of a chromosome #7.