CD4 and hepatocellular carcinoma: Although SAMHD1 is primarily regarded as a nuclear protein with an N‐terminal nuclear localization sequence, 11KRPR,14 it is found in both the nucleus and cytoplasm of CD4+ T cells and macrophages.[23] The nuclear import of SAMHD1 is mediated by the nuclear import receptors karyopherin α and β1.[24] Elevated expression of karyopherins α1 and α2 in HCC[25] may contribute to SAMHD1's increased nuclear distribution in tumors.