A 14q+ chromosome in a malignant lymphoma in a patient with Down's syndrome.

A 17-year-old Japanese boy with Down's syndrome developed leukemic lymphosarcoma; histology of a lymph node biopsy revealed a malignant lymphoma, of the poorly differentiated lymphocytic (ML-PDL) or possibly lymphoblastic type (ML-LB). The Giemsa-banding technique for chromosome analysis revealed the karyotype of the lymphoma cells to be 47, XY, + 21, 14q+. A chromosome study of PHA-stimulated lymphocytes showed a 21-trisomic pattern, i.e., 47, XY, + 21. The 14q+ marker was a product of a translocation in which the long arm of chromosome No. 8 (probable break at band q11) was translocated to the long arm of a No. 14 at band q32, which is a region usually affected in various types of lymphomas. Two normal No.8 chromosomes were present. Thus, the lymphoma cells were partially trisomic for chromosome No. 8.