The human T-cell receptor gamma (TCRG) locus at chromosome 7 consists of 21 genes. These genes are devided into 11 variable (TCRGV) genes, 3 diversity (TCRGD) gene segments, 5 joining (TCRGJ) gene segments, and 2 constant (TCRGC) genes. The TCR locus spans a region of ~156 kb on chromosome 7 band p14. Y5420 is a probe mix based on a combination of DNA and PNA technology, and contains two ready-to-use FISH DNA probes and unlabeled PNA blocking probes. The FISH DNA probes are a mixture of a Texas Red-labeled DNA probe (TCRG-Downstream) covering 290 kb centromeric to the TCRG breakpoint cluster region and a fluorescein-labeled DNA probe (TCRG-Upstream) covering 590 kb telomeric to the TCRG breakpoint cluster region.