The MLL recombinome of adult CD10⁻ BCP ALL. (A) The diagram shows the distribution of MLL fusion genes in 184 adult CD10⁻ BCP ALL patients. (B) The agarose gel shows transcripts arising from rare MLL fusions. One patient had an MLL-ACTN4 fusion, 2 others an MLL-TET1 fusion. In the first MLL-TET1–positive patient, additional bands were visible, caused by the splicing of 90-bp TET1 exon 9 and a cryptic 87-bp exon in TET1 intron 8. In all 3 patients, the reciprocal transcript was also detectable.