Specific abnormalities of chromosome 14 in patients with acute type of adult T‐cell leukemia/lymphoma

Chromosome analysis was performed on I patient with diffuse lymphoma of mixed type by histologic diagnosis and on 7 patients with the acute type of adult T‐cell leukemia (ATL). Specific abnormalities in chromosome 14 at break band q11 with the assigned locus of the α‐chain gene of the T‐cell antigen receptor were identified in 6 of 8 patients. Inv(l4) (q11q32) was found in 2 patients and translocation of chromosome 14 at break band q 11 was observed in 4. Donor chromosomes involved in translocation of the 14q11 varied, i.e., chromosomes 3, 7 or X, with the exception of one patient whose donor chromosome origin could not be determined. The breakpoint in chromosome 3 was in band p25, a region reported to include the locus of the c‐raf‐l oncogene. In chromosome 7, it was in band p11, a region reported to include the locus of the c‐erb‐B oncogene, and in the sex chromosome X, it was in band q11. One patient also had a chromosome 14 aberration at break band q32. Of the 2 remaining patients, one had lost chromosome 14 and the other had an isochro‐mosome 14q. Our observation and other reported findings suggest that the rearrangement of chromosome 14 at break band q11 is specific for lymphoma‐type or acute‐type ATL patients, and aberrations of proto‐oncogene expression or the coding sequence by recombination involving a T‐cell antigen receptor gene due to chromosome inversion or chromosome translocation may play an important role in T‐cell neoplasia including ATL.