CD5 and acute lymphoblastic leukemia: To address the outcome of different T-ALL subsets with contemporary therapy, the Children’s Oncology Group (COG) used a single central reference laboratory to classify 1144 T-ALL cases enrolled on the COG AALL0434 clinical trial between 2007 and 2014 as ETP [methodology harmonized with the approach used by Coustan-Smith et al. (1)], near ETP (ETP-ALL flow profile but positive CD5 staining), and not ETP.