Recurrent chromosome abnormalities in adult T‐cell lymphomas of peripheral T‐cell origin

Cytogenetic studies were performed on 11 Japanese patients with adult T-cell lymphoma of peripheral T-cell origin. All patients had a histologic diagnosis of diffuse lymphoma, and were treated with intensive combination chemotherapy; their median survival was 6 months. Lymphomas were categorized on the basis of the classification proposed by the Lymphoma Study Group of Japan: 5 patients had the features of pleomorphic lymphoma; 3, mixed lymphoma; 2, large-cell lymphoma; and 1, medium-sized-cell lymphoma. The modal chromosome number of abnormal cells was near-diploid in 7, and hypotetraploid in 4 including 3 patients with pleomorphic lymphoma. Abnormalities of the clonal chromosomes were observed in all 11 patients. A translocation of the short arm of 19 at band 19p13 was found in 2 patients with pleomorphic lymphoma and in one patient each with mixed lymphoma and medium-sized-cell lymphoma. A translocation of the short arm of 14, with a break at band 14p12, occurred in 4 patients with pleomorphic lymphoma. In one patient each with mixed lymphoma and large-cell lymphoma, an extra chromosome 3 was found. The numerical change was unique because their lymphomas were further categorized as "angioimmunoblastic lymphadenopathy with dysproteinemia" and "large-cell immunoblastic lymphoma", respectively. Our findings suggest that characteristic chromosome abnormalities occur in adult T-cell lymphoma, and dividing cells in the tetraploid range tend to be predominant in pleomorphic lymphoma.