Background <p>Anaplastic thyroid cancer (ATC) is a highly aggressive malignancy with rapid progression and poor prognosis. Although N1-methyladenosine (m¹A) modification has been implicated in cancer development, the specific role of tRNA m¹A modification in ATC remains unclear.</p> Methods <p>An integrated multi-omics approach is employed, including m¹A-MAP-tRNA-seq, tRNA-seq, RNA-seq, and Ribo-seq, complemented by functional assays such as tRNA aminoacylation assay, puromycin intake assay, and L-HPG staining. Additional experiments involved polysome profiling qRT-PCR, codon-switch assay, endoplasmic reticulum (ER)-tracker and TPE-MI staining, transmission electron microscopy, ChIP-qPCR, dual-luciferase reporter assay, and BODIPY staining to elucidate the underlying mechanism.</p> Results <p>TRMT6/TRMT61A is significantly upregulated in ATC. The complex promotes tumor cell proliferation and metastasis by enhancing the aminoacylation of specific tRNAs, thereby facilitating global protein translation. Elevated translation led to the accumulation of unfolded proteins in the ER, which activates the IRE1α–XBP1s pathway. Notably, m¹A modification also increased IRE1α translation, further amplifying the pathway. Activation of the IRE1α–XBP1s pathway upregulates DGAT1 expression, which promotes triglyceride synthesis.</p> Conclusions <p>Together, these findings reveal a previously unrecognized mechanism by which TRMT6/TRMT61A drives ATC progression through translational and metabolic reprogramming, identifying TRMT6/TRMT61A as a promising therapeutic target in ATC.</p> Graphical abstract <p></p>