Identification and schematic representation of theCLTC-ALKfusion transcripts. (A) RT-PCR specific for the cytoplasmic (“C”) or the extracellular (“EC”) portion of ALK in cases 1 to 3 and in fetal brain cDNA (positive control); nc indicates negative control. (B) RT-PCR performed on cases 1 and 2 (relapsed) with primers for the CLTC-ALK fusion. (C) RT-PCR for case 3 with primers for CLTC-ALK; case 2 served as a positive control. (D) Sequence of the fusion transcript/fusion protein of case 1. Exon sequences are in uppercase, intron sequences are in lowercase, and ALK sequences are in bold. Arrow indicates the genomic junction. (E) Schematic representation of the breakpoint region on the der(17) chromosome. () CLTC intron sequence present in the fusion transcript. (▦) ALK intron sequence present in the transcript. Arrow indicates the chromosomal breakpoint.