<p>This study aimed to investigate the clinical significance of tRF-18-8R1546D2 in hepatocellular carcinoma and to explore its potential role in tumor progression. tRF-18-8R1546D2 was identified as a potential oncogenic factor in HCC based on PCR Array sequencing. Its expression levels and subcellular localization in HCC were examined using qRT-PCR, FISH, and nuclear-cytoplasmic RNA fractionation. ROC curve, Cox and survival analysis were performed to determine the diagnostic and prognostic value. EdU incorporation, colony formation, apoptosis and transwell assays were conducted to assess cellular functions of tRF-18-8R1546D2. KEGG and Go analysis were conducted to seek for possible pathways in HCC progression. Bioinformatics analysis was conducted to screen potential targets of tRF-18-8R1546D2. qRT-PCR and IHC were used to examine the ECM2 expression, and its association with tRF-18-8R1546D2 was examined using correlation, dual-luciferase reporter assays and rescue assays. tRF-18-8R1546D2 was upregulated in HCC tissues, cell lines and plasma, its high expression was associated with poor prognosis and early detection. Cox analysis confirmed that tRF-18-8R1546D2 was a clinically potential prognostic marker. Functional assays revealed that overexpression of tRF-18-8R1546D2 promoted cell proliferation, migration, invasion in HCC and reduced apoptosis, the knockdown of tRF-18-8R1546D2 yielded the opposite results. ECM2 was downregulated in HCC tissues and cell lines, shown a better prognostic value and enriched in EMT pathways. Finally, Bioinformatics analysis, correlation, dual-luciferase reporter assays and rescue assays shown that tRF-18-8R1546D2 may downregulate ECM2 expression. tRF-18-8R1546D2 plays an oncogenic role in HCC and may drive tumor progression through downregulation of ECM2. Importantly, tRF-18-8R1546D2 may assist HCC detection, prognosis and treatment.</p>