Nonrandom chromosome abnormalities in lymphoma.

G-banded chromosomes were studied from involved lymph nodes or other tumor masses in 94 patients with malignant lymphoma. Clonal chromosome abnormalities were identified in 91 patients including all 81 B-lymphomas but only 6 of 9 T-lymphomas. Many recurring chromosome abnormalities were found. Most common numerical alterations involved gains of chromosomes 12 (19% of patients), 18 (13%), 7 (12%), and 21 (10%). Structural abnormalities, which were more frequent than numerical alterations, most commonly involved chromosome regions 14q (71% of patients), 18q (36%), 6q (31%), 1p (24%), and 8q (19%). Seven recurring translocations were identified, and all except one involved 14q32. The most frequent were t(14;18)(q32;q21) in 22 patients, t(8;14)(q24;q32) in 9 patients, and t(1;14)(q42;q32) in 3 patients. Deletions most frequently involved the long arm of chromosome 6 at band q21 (11 patients) or q23 (7 patients). The common recurring chromosome abnormalities were correlated with histology (International Working Formulation for Clinical Usage) and immunological phenotype. Four abnormalities were significantly associated with specific histologies. Eighteen (82%) patients with t(14;18)(q32;q21) were follicular. Similarly, 82% of patients with del(6)(q21) were large cell lymphomas. Lymphomas with trisomy 7 were either diffuse large cell or follicular, while patients with t(8;14)(q24;q32) were either diffuse large cell or small noncleaved cell. A significant association with immunological phenotype was seen for t(14;18) only. All patients were either B- or complement lymphomas, and the heavy chain(s) was more commonly gamma and less frequently delta mu than among the total B-lymphoma population. We conclude that essentially all lymphomas have cytogenetic abnormalities; further study is required to determine their significance. Particularly, it will be of interest to see if oncogenes are found in the regions of these chromosome abnormalities.