CD19 and acute lymphoblastic leukemia: The selection of antigens was made based on available literature data reporting the high frequency of overexpression, as well as utility in BCP-ALL monitoring of such markers as CD86 (16, 27), CD66c, CD304 (used in BCP-ALL MRD panel designed by the EuroFlow Consortium) (28, 29) and CD72, a pan-tumor antigen, suggested as a potential key marker for patients with loss of CD19 expression after immunotherapy, and commonly expressed in BCP-ALL (20, 30).