However, the addition of Kyn diminished the inhibitory effect of LM10 on LNCaP-EnzR xenograft tumour growth in vivo but not that of CH223191 (Fig. 3m; Supplementary Fig. S14c), suggesting that Kyn participates in mediating the growth of TDO2-promoted recurrent CRPC in vivo. Here, TDO2 is linked to neoplasm.