CD47 and anemia (phenotype): Nevertheless, we used SIRT6, but not CD47, as our following therapeutic target because the potential risk of hematotoxicity of CD47 targeting agents still cannot be avoided despite various methods being used to mitigate such toxicity (particularly anemia).[52] By exploring the upstream regulator, the longevity gene SIRT6 was screened as a monitor of the CD47 checkpoint via the regulatory mechanism of transcriptional pausing.