ARPP21 and acute lymphoblastic leukemia: Meanwhile, the 26-Mb deletion on chromosome 3 encompasses a large number of genes, including SETD2, which is associated with chemotherapy resistance and relapse when co-occurring with ETV6 deletions (Mar et al, 2017; Oshima et al, 2020); ARPP21, a frequent deletion in ETV6::RUNX1-like ALL cases (Zaliova et al, 2017); and FHIT, a tumor suppressor gene that has been shown to be abnormally expressed in ALL (Hallas et al, 1999).