Augmented Expression of the IL3RA/CD123 Gene in MLL/KMT2A-Rearranged Pediatric AML and Infant ALL

Here, we evaluated transcript-level IL3RA/CD123 expression in mixed lineage leukemia 1 (MLL) gene/KMT2A-rearranged (MLL-R+) vs. MLL-R− pediatric AML as well as infant ALL by comparing the archived datasets of the transcriptomes of primary leukemic cells from the corresponding patient populations. Our studies provide unprecedented evidence that IL3RA/CD123 expression exhibits transcript-level amplification in MLL-R+ pediatric AML and infant ALL cells. IL3RA was differentially upregulated in MLL-AF10+ (2.41-fold higher, p-value = 4.4 × 10−6) and MLL-AF6+ (1.83-fold higher, p-value = 9.9 × 10−4) but not in MLL-AF9+ cases compared to other pediatric AML cases. We also show that IL3RA/CD123 expression is differentially amplified in MLL-AF4+ (1.76-fold higher, p-value = 2.1 × 10−4) as well as MLL-ENL+ infant ALL (1.43-fold higher, p-value = 0.055). The upregulated expression of IL3RA/CD123 in MLL-R+ pediatric AML and infant ALL suggests that CD123 may be a suitable target for biotherapy in these high-risk leukemias.