Prognostic impact and clinical value of low levels of flow cytometric MRD at the end of induction in childhood B‐lineage acute lymphoblastic leukemia: Results of study ALL‐MB 2015 - Alexander Popov; Guenter Henze; Julia Roumiantseva; Oleg Budanov; Ekaterina Mikhailova; Polina Lavrova; Tatiana Verzhbitskaya; Zhan Permikin; Grigory Tsaur; Svetlana Lagoyko; Liudmila Zharikova; Natalia Miakova; et al. (HemaSphere)