Molecular equivalents of chromosomal translocations generate either a qualitative change due to the expression of a chimaeric, relatively tumour specific, protein, such as the NPM-ALK associated with the t(2;5) in ALCL or a quantitative change in the extent, stage or site of expression of a full length protein, due to its juxtapositioning to and deregulation by an Ig or TCR gene.     ///    "At diagnosis, immunological detection of the deregulated 'protooncogene' may well provide the simplest, most appropriate screening technique for CCND1 and NPM-ALK induced ALK expression. "