A 3' tRNA-derived fragment produced by tRNA and tRNA is associated with poor prognosis in B-cell chronic lymphocytic leukemia, independently of classical prognostic factors.

OBJECTIVE

3' tRNA-derived fragments (3' tRFs) are important epigenetic regulators in normal and pathological conditions. In this study, we aimed to explore the potential value of a 3' tRF as a prognostic and/or screening biomarker for B-cell chronic lymphocytic leukemia (B-CLL).

METHODS

Publicly available next-generation sequencing data from 20 B-CLL cases were analyzed, followed by prediction of targets of the most abundantly and ubiquitously expressed 3' tRFs, leading to selection of tRF-Leu . PBMCs were isolated from blood samples of 91 B-CLL patients and 43 non-leukemic donors, followed by total RNA extraction, in-vitro polyadenylation, and first-strand cDNA synthesis. Next, a real-time quantitative PCR (qPCR) assay was developed for the accurate quantification of tRF-Leu and applied in all samples, prior to biostatistical analysis.

RESULTS

High tRF-Leu levels are associated with inferior overall survival (OS) of B-CLL patients. The unfavorable significance of tRF-Leu was independent of established prognostic factors in B-CLL. Stratified Kaplan-Meier OS analysis uncovered the unfavorable prognostic role of high tRF-Leu levels for patients in Binet A or Rai I stage, negative CD38 expression, mutated, or unmutated IGHV genomic locus.

CONCLUSION

Our approach revealed the independent prognostic value of a particular 3' tRF, derived from tRNA and tRNA (tRF-Leu ) in B-CLL.