Human DUS2 has been implicated as a cancer targetbased upon its overexpression in nonsmall cell lung carcinomas (NSCLC);therefore, identifying small molecule inhibitors for hDUS2 can havetherapeutic value.10 We envisioned thatour mechanism-based cross-linking assay with 5-BrUrd-modified tRNAcould provide a useful method to screen direct inhibitors of hDUS2activity (Figure 5a),particularly since no high-throughput DUS activity assays have beendescribed. This evidence concerns the gene DUS2 and cancer.