CP and acute lymphoblastic leukemia: In our study, the PAX5alt subtype most frequently appeared in multiclass prediction sets generated using ALLIUM3 and ALLSorts.4 Given that alterations in the PAX5 gene are observed in over one third of patients with B-cell precursor ALL, as reported in prior studies,32,44 the multiclass CP sets containing PAX5alt may not solely indicate classifier uncertainty but could also point to biologically relevant secondary aberrations with potential clinical importance.