Chromosomal and immunophenotypic patterns in T cell acute lymphoblastic leukemia (T ALL) and lymphoblastic lymphoma (LBL).

In this study of 33 T cell acute lymphoblastic leukemia (T ALL) and 17 lymphoblastic lymphoma (LBL) patients, no relevant differences between the two groups were observed in clinical characteristics, response to therapy, and survival. We found translocations involving 14q11, 7q35, or 7p15, where T cell receptor alpha and delta, beta, and gamma subunit genes reside, in 20 patients (40%). Most of these translocations were seen with equal frequency in T ALL and LBL, indicating that, in a large proportion, the two diseases are different manifestations of the same lymphoblastic disorder. However, other translocations, such as t(9;17)(q34;q23), occurred only in LBL, perhaps pointing to the existence of subsets of LBLs that are distinct from T ALL. On the basis of karyotype, 50 patients could be classified into three groups: 20 patients with 14q11, 7q35, or 7p15 translocations (group A); 20 with other translocations, and/or deletions (group B); and 10 with normal diploidy (group C). There was no difference in survival time between any two of the three groups.