tRNA-Derived Fragments (tRFs) in Bladder Cancer: Increased 5'-tRF-LysCTT Results in Disease Early Progression and Patients' Poor Treatment Outcome

The heterogeneity of bladder cancer (BlCa) prognosis and treatment outcome requires the elucidation of tumors' molecular background towards personalized patients' management. tRNA-derived fragments (tRFs), although originally considered as degradation debris, represent a novel class of powerful regulatory non-coding RNAs. In silico analysis of the TCGA-BLCA project highlighted 5'-tRF-LysCTT to be significantly deregulated in bladder tumors, and 5'-tRF-LysCTT levels were further quantified in our screening cohort of 230 BlCa patients. Recurrence and progression for non-muscle invasive (NMIBC) patients, as well as progression and patient's death for muscle-invasive (MIBC) patients, were used as clinical endpoint events. TCGA-BLCA were used as validation cohort. Bootstrap analysis was performed for internal validation and the clinical net benefit of 5'-tRF-LysCTT on disease prognosis was assessed by decision curve analysis. Elevated 5'-tRF-LysCTT was associated with unfavorable disease features, and significant higher risk for early progression (multivariate Cox: HR = 2.368; p = 0.033) and poor survival (multivariate Cox: HR = 2.151; p = 0.032) of NMIBC and MIBC patients, respectively. Multivariate models integrating 5'-tRF-LysCTT with disease established markers resulted in superior risk-stratification specificity and positive prediction of patients' progression. In conclusion, increased 5'-tRF-LysCTT levels were strongly associated with adverse disease outcome and improved BlCa patients' prognostication.