Unleashing lncRNA THOR: roles in cancer progression and clinical outlook

Testis-associated highly conserved oncogenic long non-coding RNA (lncRNA THOR) is highly expressed in normal testis tissue and in at least 15 types of tumours. Since its discovery in 2017, more than 20 studies have investigated its potential tumour-regulatory functions; however, a comprehensive review of these findings remains unavailable. This review aims to address this gap by synthesizing current research to provide an overview of the mechanisms through which lncRNA THOR regulates tumourigenesis and its potential clinical applications. In addition to enhancing insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) expression or activity, lncRNA THOR modulates several pathways, including protein kinase B (AKT), AMP-activated protein kinase (AMPK), ß-catenin, interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3), and Yes-associated protein (YAP), thereby promoting tumourigenesis. In contrast to several other well-characterized lncRNAs, current literature does not clearly indicate that lncRNA THOR functions as a microRNA (miRNA) sponge or is involved in the progression of haematological malignancies, which warrants further investigation. Nonetheless, its consistent upregulation in diverse tumours and its association with poor clinical outcomes suggest that lncRNA THOR may serve as a diagnostic and prognostic biomarker. Targeting lncRNA THOR could also inhibit tumourigenesis. Consequently, large-scale clinical trials and mechanistic studies are required to validate the sensitivity, reliability, and specificity of lncRNA THOR as a biomarker or therapeutic target in cancer management.