Thyroid neoplasias are frequently associated with chromosomal rearrangements, but the molecular bases of such peculiarity are not completely understood. Recently it has been proposed that the spatial proximity of translocation-prone gene loci is a contributing factor in the formation of specific cancerous chromosomal translocation. Loci proximity has been demonstrated to play a role in the H4/RET oncogenic rearrangement in papillary thyroid carcinomas. Roccato et al. explored whether the spatial proximity is a contributing factor in the generation of the thyroid-specific TPR/NTRK1 chimeric oncogenes, produced by chromosome 1 inversions involving the TPR and NTRK1 genes. The distance between TPR and NTRK1 loci was determined by two-color fluorescent in situ hybridization (FISH) and two-dimensional microscopy. The cover image shows two-color FISH in normal thyroid interphase nuclei with the TPR probe (red spots) and the NTRK1 probe (green spots). Analysis of the data determined that TPR and NTRK1 loci are in close proximity in thyrocytes but not in peripheral blood lymphocytes used as control. These data support the notion that oncogenic rearrangements are enhanced by relative loci proximity. For details, see the article by Roccato et al. on page 2572 of this issue.