Twelve (9%) of 131 unselected T-cell acute lymphoid leukemias (T-ALLs) expressed CALM-AF10 by reverse transcription-polymerase chain reaction or fluorescence in situ hybridization (or both), including 8% of children and 10% of adults, of whom only half demonstrated a t(10;11) by classical cytogenetics.     ///     The t(10;11)(p13-14;q14-21) associated with CALM-AF10 is considered to be rare and associated with a variety of acute lymphoid and myeloid leukemias.     ///    CALM-AF10 is a common fusion transcript in T-ALL and is specific to the TCRgammadelta lineage..     ///    "Nine of 12 immature CALM-AF10 T-ALLs demonstrated 3' fusion transcripts, whereas 6 of 7 TCRgammadelta T-ALLs demonstrated 5' fusion transcripts. "    ///    "CALM-AF10 was not found in T-cell-receptor alphabeta (TCRalphabeta) lineage T-ALLs, as defined by expression of TCRalphabeta, cytoplasmic TCRbeta, or TCRbetaVDJ rearrangement in immature cytoplasmic TCRbeta- cases, compared with 19% of TCRgammadelta T-ALLs and 33% of immature delta/gamma T-ALLs. "    ///    CALM-AF10 is therefore the most common fusion protein in T-ALL. 