Copy number alteration (CNA) profiles were similar to B‐other ALL, although CRLF2‐r patients harbored higher frequencies of IKZF1 (60/138, 43% vs. 77/1351, 24%) and BTG1 deletions (20/138, 15% vs. 3/1351, 1%). The gene discussed is BTG1; the disease is acute lymphoblastic leukemia.