Plasma tsRNAs as novel diagnostic biomarkers for renal cell carcinoma

Plasma tsRNAs as novel diagnostic biomarkers for renal cell carcinomaDear Editor, Early diagnosis greatly benefits renal cell carcinoma (RCC) patients with remarkable higher survival. 1Whereas, no appropriate liquid-biopsy biomarkers has been applied to RCC diagnosis in clinic so far. 2 Transfer RNA-derived small RNAs (tsRNAs), a class of newly discovered noncoding RNAs, are stable and abundant in circulation, promising in noninvasive early diagnosis of cancer. 3,4Here, we explore the diagnosis values and biological functions of plasma tsRNAs in RCC for the first time.The study was evaluated and authorised by the Ethics Committee of Nanjing Drum Tower Hospital (2021-582-01).The research route diagram was shown in Figure S1.First, to explore the distinct plasma tsRNA expression profile in RCC patients, we performed small RNA sequencing using RNA extracted individually from plasma of five RCC patients and five healthy controls.The tsRNA expression profile in plasma of RCC patients were obviously changed (Figure 1A), and among 657 tsRNAs detected, 71 tsRNAs were significantly altered (Figure 1B).Considering the tsRNAs expression levels (CPM > 10) and length (due to the length limitation, the length of tsRNAs should ≥ 17 nt when assessed by RT-qPCR), we selected 12 tsRNAs for further validation in an independent training set (30 healthy controls and 32 RCC patients) using RT-qPCR.The detection limits of RT-qPCR assay using tsRNA specific primers were evaluated by the standard curves developed with corresponding synthetic tsRNA oligonucleotides (Figure S2, Table S1).In this training set, 5 out of the 12 tsRNAs (tRF-19-DRMD5112, tRF-18-8R6Q46D2, tRF-17-884U1D2, tRF-17-8SOUPR2 and tRF-28-87R8WP9I1E0K) were significantly reduced in RCC patients, which was also consistent with the sequencing data (Figure 1C; Tables S2 andS3).Whereafter, the levels of these 5 tsRNAs were further confirmed in another larger validation set (99 healthy controls and 120 RCC patients), and showed a consistent trend (p < .0001for all tsRNAs; Figure 2A and Table S4).Combining the training and Meng Ding and Wanqing Zhou contributed equally.