Chromosome 14q+ in adult T-cell leukemia.

Cytogenetic studies were performed on leukemic cells from two patients with adult T-cell leukemia. A 14q+ marker chromosome was found in the peripheral blood leukocytes from patient No. 1 and in a leukemic T-cell line (MT-1) derived from the peripheral blood of patient No. 2. The 14q+ resulted from a t(12;14) in patient No. 1 and from a t(Y;14) in patient No. 2 with a break point at 14q32 in each case. In addition, the leukemic cells from patient No. 1 showed a t(1;7) and a 9q-, while the MT-1 line had numerous structural abnormalities. Thus, it is clear that a 14q+ translocation is not restricted to B-cell neoplasms but occurs in T-cell neoplasms as well.