Outcome and lineage involvement in t(12;21) childhood acute lymphoblastic leukaemia

The t(12;21)(p13;q22) translocation has been described recently as the most recurrent genetic lesion in paediatric acute lymphoblastic leukaemias (ALLs). It has also been associated with B-precursor lineage involvement and good outcome. We tested 51 diagnostic paediatric ALLs and found 11 cases with molecular evidence of the t(12;21). Interestingly, amongst t(12;21) positive patients, we report three cases with hybrid phenotype, and two cases showing an aggressive and fatal disease. Our data show that the t(12;21) does not represent an independent good-risk indicator. Long follow-ups and additional molecular investigations are needed to assess the prognostic and pathogenetic relevance of t(12;21) in childhood ALLs.