A recent study further demonstrated that TDO2 is targeted by miR-200 in breast cancer and that the overexpression of TDO2 brings about enhanced anchorage-independent growth [148], suggesting that miR-200 can inhibit anchorage-independent cell growth through repressing EMT process mediated by the TDO2/kynurenine/AHR signaling (Figure 2 and Table 2). Here, TDO2 is linked to breast cancer.