Activation of HOX11L2 by juxtaposition with 3′‐ BCL11B in an acute lymphoblastic leukemia cell line (HPB‐ALL) with t(5;14)(q35;q32.2)

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. © 2003 Wiley‐Liss, Inc.