Lack of expression of the recombination activating genes RAG-1 and RAG-2 in cutaneous T-cell lymphoma: pathogenic implications.

Analyses of the karyotype and genome of cutaneous T-cell lymphoma (CTCL) cells have shown that they contain chromosome breaks and translocations. The sequence analyses of such DNA breakpoints found in various kinds of leukaemias have suggested that some of the observed translocations have been caused by illegitimate V(D)J (v = Variability; D = diversity; J = joining) recombination. To study whether illegitimate V(D)J recombination is responsible for the continuously increasing number of DNA breaks in CTCL, we used reverse transcriptase polymerase chain reaction (RT-PCR) to analyse three CTCL cell lines and biopsies from 14 CTCL patients for the expression of the RAG-1 and RAG-2 genes which are essential for V(D)J recombination. We found no RAG gene expression in any of the 17 samples analysed, indicating that illegitimate V(D)J recombination may not be the reason for the increased number of chromosomal aberrations and translocations in CTCL cells.