For instance,while using our αCD206-synNotch to target CD206+ macrophages,the receptor is likely to report cell contact with B cells (CD19+), which are abundant at both the primary tumor and metastaticsites.1 Moreover, the activation of synNotchreporter cells by nontarget immune cells is likely to occur shortlyafter injection while circulating in the bloodstream and prior tothe establishment of primary and secondary tumors in mice. This evidence concerns the gene CD19 and neoplasm.