TYW2 is an S-adenosyl-L-methionine-dependent methyltransferase that catalyzes a critical step in wybutosine biosynthesis, specifically transferring the alpha-amino-alpha-carboxypropyl group to 4-demethylwyosine at position 37 of phenylalanine tRNA 1. Wybutosine is a hypermodified guanosine essential for stabilizing codon-anticodon interactions during ribosomal translation 1. TYW2 functions as a component of a multi-enzyme complex catalyzing sequential biosynthetic reactions 1. In cancer biology, TYW2 plays a paradoxical role. TYW2 loss or epigenetic silencing occurs in colorectal and other cancers, leading to hypomodification of tRNAPhe and increased ribosomal frameshifting events 2. This frameshift-induced translational dysregulation generates immunogenic out-of-frame peptides that enhance tumor immunogenicity and sensitivity to PD-1 checkpoint blockade 3. Conversely, TYW2 downregulation promotes taxol resistance in cancer cells by accumulating the precursor 4-demethylwyosine 4. TYW2 epigenetic inactivation correlates with poor overall survival in early-stage colorectal cancer and enhanced cellular migration properties 2. These findings reveal that TYW2-mediated tRNA modification represents a novel axis in cancer immunotherapy and chemotherapy resistance.