Molecular analysis of the CALM/AF10 fusion: identical rearrangements in acute myeloid leukemia, acute lymphoblastic leukemia and malignant lymphoma patients

The recurring translocation t(10;11)(p13;q14) which is found in acute myelo id leukemia (AML) and in acute lymphoblastic leukemia (ALL) results in the fusion of the putative transcription factor AF10 to CALM encoding a clathri n assembly protein. Previous studies using mainly fluorescence in situ hybr idization (FISH) analysis have shown that the CALM/AF10 rearrangement is fo und in immature acute myeloid leukemia (AML) of subtype MO and M1 and in T cell ALL. In this study we analyzed the CALM/AF10 and AF10/CALM fusion mRNA s in a series of three patients with AML, one patient with T-ALL and two pa tients with precusor T lymphoblastic lymphoma. In all six patients the brea kpoint in CALM is at the 3' end of the coding region (nt1926/1927 or nt 209 1/2092). Three breakpoints could be identified in AF10 (nt 588/589, nt 882/ 883 and nt 978/979). These data demonstrate that the CALM/AF10 fusions foun d in patients differ only slightly with respect to the portion of AF10 pres ent and that there is no obvious difference between the fusions found in AM L patients compared to those found in patients with lymphoid malignancies.