Molecular characterization of del(11)(p12p13) in T-ALL patients 1950 and 2846. (A) Long-range PCR analysis on genomic DNA of patient 1950 using primers situated in intron 1 of RAG2 and intron 1 of LMO2 revealed a specific band of approximately 2000 bp. Patient 2720 served as a negative control. (B) Sequence analysis confirmed the exact position of the genomic breakpoint. (C) PCR analysis on cDNA of this patient revealed a RAG2-LMO2 fusion gene, in which exon 1 of RAG2 was fused to exon 2 of LMO2. (D) Gene (exon) structure of both RAG2 and LMO2 shows that the translation initiation sites are situated in exon 2 and exon 4, respectively. As a consequence, translation of the RAG2-LMO2 fusion gene will also be initiated in exon 4. (E) LM-PCR analysis on HincII-digested genomic DNA from patient 2846 using an LMO2 intron 1-specific primer revealed an aberrant PCR product of approximately 600 bp. The expected wild-type product is approximately 1000 bp and is visible in both patients 2846 and 2720, who served as a negative control. (F) Sequence analysis confirmed that in patient 2846 the LMO2 intron 1 sequences are fused to a genomic region upstream of RAG2. prom indicates promoter.