Consistently, PRPS1 2A mutant tumors were more sensitive to etoposide than PRPS1 WT tumors, just as in the PRPS1-deficient group (Fig. 5c,f), indicating that PRPS1 O-GlcNAcylation confers lung cancer cell resistance to chemoradiotherapy. The gene discussed is PRPS1; the disease is lung cancer.