UPB1 and cancer: The gene causing the strongest effect, DPYS, was found as essential in the catalog of cancer dependencies.56 The second predicted gene, UPB1, encodes an enzyme (β-ureidopropionase) that catalyzes the last step in the pyrimidine degradation pathway, required for epithelial-mesenchymal transition.58 Using a cancer model of gastric adenocarcinoma (AGS cell line) we carried out a cell proliferation experiment upon depletion of UPB1 gene expression.