We aimed to investigate the regulation of B-lineage specification and commitment gene expression by EGR3 in patient material and therefore assessed the transcription levels of IGHM, CD79A, BLK, and PTPN6 in 50 infant KMT2A::AFF1 proB-ALL patients at diagnosis (Table 1). The gene discussed is BLK; the disease is acute lymphoblastic leukemia.