NUP214 and ABL1 exons. (A) In most ABL1 fusion genes (eg, BCR-ABL1), ABL1 exon 2 is fused to the partner gene, but fusion genes with ABL1 exon 3 have occasionally been described (both exons are in the same reading frame). NUP214 exons that could be joined in-frame with either ABL1 exon 2 or 3 are shaded. PCR primers were located in ABL1 exon 3 and in the 3′ part of NUP214 exons 2, 6, 10, 13, 20, 22, 26, 29, 31, and 34. (B) Agarose gel of NUP214-ABL1-positive cases. Lane 1, cell line BE-13 (transcript nup34a2); lane 2, cell line ALL-SIL (transcript nup32a2); lanes 3-13, patient samples as described in Table 1; lanes 14 and 19, ϕX174 size standard; lanes 15-18, multiplex PCR with H₂O (lane 15), NUP214-ABL1-negative cDNA (lane 16), and positive samples (lanes 17, 18).