SAMHD1 and cancer: In fact, ectosolic 5′-nucleotidase promotes cancer not only through the production of ectosolic Ado: cytosolic 5′-nucleotidase regulates proliferation and apoptosis in a way not so easily attributable to its regulation of intracellular nucleotide concentration, IMPDH also acts as transcription factor, and, finally, SAMHD1 binds to single-stranded RNA.