It has been shown that the cytotoxicity of 5‐FU is ascribed to the misincorporation of fluoronucleotides into RNA and DNA, leading to DNA damage response (DDR) and apoptosis.15, 16 We therefore reasoned that PRPS1 mutant could allow enhanced apoptosis for Reh ALL cells with the treatment of 5‐FU. This evidence concerns the gene PRPS1 and acute lymphoblastic leukemia.