PRPS2 and cancer: The de novo purine biosynthesis and purine salvage pathways serve as nucleotide providers for cell growth (G1), the synthesis of genetic materials (S), division (G2) and mitosis (M), which are made possible through the up-regulation of phosphoribosylpyrophosphate synthetase 2 (PRPS2) activity, an enzyme catalyzing the first reaction in nucleotide synthesis and linked to cancer progression [28].