Amplification of the TCL1 flanking region at 14q32.1 with no TCL1 gene transcription in a patient with peripheral T cell lymphoma

Cytogenetic and molecular-genetic characteristics in peripheral T cell lymphoma (PTL) have not been well defined, except for those in adult T cell leukemia/lymphoma (ATL/L). Translocations and inversions involving a chromosome band 14q32 were extremely common abnormalities reported in PTL and ATL/L. We studied the involvement of TCL1, a recently isolated gene located in 14q32.1, in tumor tissues from 20 patients with PTL including three with 14q32 translocations by two color fluorescent in situ hybridization (FISH) using two cosmid probes flanking the TCL1 gene. The two cosmid signals were separated in none of them, but much increased in number in one tumor without 14q32 translocation, indicating that the TCL1 genomic region was amplified in this tumor. Reverse transcription-polymerase chain reaction (RT-PCR), however, failed to detect the TCL1 transcript in the tumor. These findings suggest that an oncogene other than TCL1 may be located in 14q32.1, and its amplification may be involved in the neoplastic process of PTL.