Cooperative Genetic Changes in Pediatric B-Cell Precursor Acute Lymphoblastic Leukemia with Deletions or Mutations of IKZF1

• In contrast to IKZF1 deletions (IKZF1), IKZF1 sequence mutations (mutIKZF1) have been reported to be rare in B-cell precursor acute lymphoblastic leukemia and their clinical implications are unknown. We performed targeted deep sequencing of all exons of IKZF1 in 140 pediatric cases, eight (5.7%) of which harbored a mutIKZF1. The probabilities of relapse (pRel) and event-free survival (pEFS) did not differ between cases with or without mutIKZF1, whereas pEFS was decreased and pRel increased in IKZF1-positive case. Coexisting microdeletions, mutations (FLT3, JAK2, SH2B3, and SPRED1), and rearrangements (ABL1, CRLF2, JAK2, and PDGFRB) in 35 IKZF1 and/or mutIKZF1-positive cases were ascertained using fluorescence in situ hybridization, single nucleotide polymorphism array, Sanger, and targeted deep sequencing analyses. The overall frequencies of copy number alterations did not differ between cases with our without IKZF1/mutIKZF1. Deletions of HIST1, SH2B3, and the pseudoautosomal region (PAR1), associated with deregulation of CRLF2, were more common in IKZF1-positive cases, whereas PAR1 deletions and JAK2 mutations were overrepresented in the combined IKZF1/mutIKZF1 group. There was no significant impact on pRel of the deletions in IKZF1-positive cases or of JAK2 mutations in cases with IKZF1/mutIKZF1. In contrast, the pRel was higher (P=0.005) in IKZF1/mutIKZF1-positive cases with PAR1 deletions. (c) 2015 Wiley Periodicals, Inc.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Pediatrik (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Pediatrics (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Medicinsk genetik (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Medical Genetics (hsv//eng)

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