STAT3 and cancer: In cancer cachexia, muscle mitochondrial dysfunction may occur in part through cytokine-signalling such as IL-6 – STAT3 axis [2], confirmed by this study; alternatively or complementary to this, reduced physical activity observed in these TB-mice [4] may contribute to the process of dysregulated mitochondria [2] that per se may be sufficient to induce muscle atrophy [36].