IDO1 and Cachexia: Molecular pathways were analysed via western blot and qPCR.<h4>Results</h4>Compared to LLC mouse models, Ido1-OE significantly exacerbated tumour growth and cachexia, leading to a significant decrease in lean body weight, gastrocnemius and tibialis anterior muscle weights (p < 0.01, p < 0.0001, p < 0.001).