IGFBP6 and hepatocellular carcinoma: Therapeutically, repeated attempts to inhibit the IGF axis in HCC underscore that pathway blockade is feasible but demands precise patient selection and on-pathway pharmacodynamic readouts; integrating IGFBP-6 abundance and Ser204 O-GlcNAc status could refine these selection criteria by indexing how much IGF-II is effectively sequestered in vivo [110].