t(4;11)(q21;p15), including one complex translocation t(1;4;11)(p32;q21;p15), in adult T-cell acute lymphoblastic leukemia

A der(11)t(4;11)(q21;p15) in a T-ALL/LBL patient

Translocation t(4;11)(q21;p15) is a rare recurrent change associated to T-cell acute leukemia. In most cases, this alteration appears as the only abnormality or as part of a simple karyotype. In this report, we present the first case of T acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) with the unbalanced translocation der(11)t(4;11)(q21;p15) as part of a very complex karyotype with multiple chromosome abnormalities, most of them not previously described in the literature. FISH (fluorescence in situ hybridization) and spectral karyotype (HiSKY) analysis confirmed the presence of complex alterations. The patient, a 16-year-old male, showed poor response to treatment and short survival (11 months). A detailed review of previously reported cases with t(4;11)(q21;p15) is also provided. The description of this type of alterations may contribute to the identification of new molecular mechanism associated to neoplastic development.

Cytogenetic Studies in T-Cell Acute Lymphoblastic Leukemia (1981 – 2002)

Chromosomal analysis was successfully performed in 34 of the 37 patients with T-cell acute lymphoblastic leukemia (ALL) seen at the University Hospital in Brest (France) between 1981 and 2002. A normal karyotype was observed in 29.4% of the patients. Numerical changes were rare, 79.2% of the abnormal karyotypes being pseudodiploid. All 24 abnormal karyotypes had at least a structural rearrangement. Translocations involving band 14q11, that contains the T-cell receptor (TCR) alpha and delta-genes, were observed in 8 patients; in 3 of them, a new partner chromosomal band was found. The short arms of chromosomes 11 and 12 were involved in 3 and 2 translocations respectively. Three patients had a del(6q). Our results are in agreement with those of the literature. Most of the recurrent abnormalities are different from those of B-lineage ALL. Some are known to involve TCR genes whereas others can lead to the discovery of new genes that are important to T-lineage leukemogenesis.