Molecular characterization of a novel chromosomal translocation t(12;14)(q23;q11.2) in T-lymphoblastic lymphoma between the T-cell receptor delta-deleting elements (TRDREC and TRAJ61) and the hypothetical gene C12orf42.

Chromosomal aberrations have diagnostic, prognostic, and therapeutic relevance in hematologic malignancies. By combining fine-tiling comparative genomic hybridization (FT-CGH) and ligation-mediated PCR (LM-PCR), we established a fast, robust approach to precisely characterize chromosomal breakpoints. Using this approach, we clarified at the molecular level novel chromosomal translocation t(12;14)(q23;q11.2) in T-lymphoblastic lymphoma. The translocation occurred during the deletional rearrangement of the T-cell receptor delta gene (TRD), which is a pivotal step in T cell differentiation toward the alpha/beta vs. the gamma/delta lineage. We found that this rearrangement disrupted the hypothetical gene C12orf42 and brought the Achaete-scute complex homolog 1 gene into proximity of the TRA enhancer, which encodes a member of the basic helix-loop-helix family of transcription factors and is overexpressed in thyroid and lung cancers.