Frequency of BCR-ABL1-like, IKZF1-deleted, and CRLF2-high mRNA expression features among children with BCR-ABL1–negative, MLL wild-type BCP-ALL. (A) Distribution of cases with BCR-ABL1-like, IKZF1-deleted, and/or CRLF2-high mRNA expression in 507 children with BCR-ABL1–negative, MLL wild-type BCP-ALL. See also supplemental Table 5A. (B) Pie chart depicting the distribution of patients carrying 1 or more of the aforementioned features. Collectively, these 3 features constitute 33.7% of BCR-ABL1–negative, MLL wild-type BCP-ALL cases as shown in panel A. See also supplemental Table 5A. (C) Pie chart depicting the percentages of relapsed patients carrying 1, 2, or 3 features. In total, 62.9% of all relapsed cases were associated with BCR-ABL1-like and/or IKZF1-deleted features. See also supplemental Table 5B.