IKZF1 (IKAROS) deletions in B-ALL and its clinical correlation: a prospective study from a tertiary care centre in Northern India

Abstract

Introduction: IKZF1 deletions have been reported with variable frequency in B-ALL. This study was carried out to find the prevalence and profile of IKZF1 deletions and their correlation in B-ALL. Methods: The untreated B-ALL cases were prospectively analyzed for IKZF1 deletions over a period of eleven months using multiplex ligation dependent probe amplification (MLPA). The IKZF1 deletions were classified into three functional groups—dominant negative, haploinsufficiency and others. The response to induction chemotherapy was correlated with the IKZF1 deletion status. Results: The median age of 101 cases was 7 years (1–67) with 82 pediatric (<18 years) cases. Fifteen cases were positive for BCR-ABL. The IKZF1 deletions were detected in 29 (28.7%) cases; 53% BCR-ABL positive, 24% BCR-ABL negative, 47% adult and 24% pediatric cases. Out of the 29 deletions, 19 (66%) were haploinsufficiency, 8 (28%) were dominant negative and 2 others. The IKZF1 deleted cases had higher induction failure rates compared to the cases without IKZF1 deletions. Conclusions: The IKZF1 deletions were detected in 28.7% B-ALL patients. These were more common in BCR-ABL positive and adult B-ALL compared to the BCR-ABL negative and pediatric cases, respectively. The haploinsufficiency was commoner than dominant negative IKZF1 deletions. IKZF1 deletions correlated with higher induction failure.