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

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.