Activation of HOX11L2 by juxtaposition with 3'-BCL11B in an acute lymphoblastic leukemia cell line (HPB-ALL) with t(5;14)(q35;q32.2)

Abstract

Cytogenetic analysis of a pediatric T-cell acute lymphoblastic leukemia (ALL) cell line (HPB-ALL) revealed the cryptic t(5;14)(q35;q32.2), recently found in 15-20% pediatric T-ALL patients, with 5q35 and 14q32.2 breakpoints at 5'-HOX11L2 and 3'-BCL11B, respectively. Expression of both BCL11B, which is hematologically restricted to T cells, and HOX11L2 was detected, whereas adjacent genes at 5q35 (RANBP17) and 14q32 (VRK1, HSU88895) were not dysregulated. Apparently, t(5;14)(q35;q32.2) serves to activate HOX11L2 by juxtaposition with elements downstream of BCL11B, implying a novel dysregulatory mechanism comparable to TCRA/D or IGH juxtaposition. As well as providing molecular cytogenetic documentation of t(5;14) ALL, this report validates HPB-ALL cells for investigating this important new disease entity in vitro.