CD70 and acute myeloid leukemia: Sauer et al., investigated several anti-CD70 CAR constructs with different hinges (IM, LF) and costimulatory molecules (CD27, CD28, and 4-1BB) and they report significant in vitro and in-vivo tumor-killing with LF-28z and CD27z CAR T-cells in two AML xenograft models without HSC colony assay toxicity (29).