TPO and lung cancer: Zhang et al. demonstrated that the lung cancer cell line A549 had an obvious preference for liver metastasis when it expressed a high level of CD133.150 Wu et al. showed that CRC CTCs expressing CD110, the thrombopoietin (TPO)-binding receptor, were modulated by TPO-mediated lysine catabolism and TPO reprogramming and therefore exhibited a significant preference for the liver.151 Lysine catabolism contributes to the self-renewal of CTCs and enhances the antioxidant capacity of CTCs, which assists in the survival and successful colonization of CTCs in the liver.