[Indoleamine 2, 3-dioxygenase activity during neoadjuvant chemotherapy in patients with breast cancer].

We evaluated the significance of indoleamine 2, 3-dioxygenase (IDO) in breast cancer patients during neoadjuvant chemotherapy. IDO activity can be determined by the tryptophan( Trp)/kynurenine( Kyn) ratio. Trp and Kyn were measured by high performance liquid chromatography (HPLC). The correlations between the Trp/Kyn ratios in the pre-chemotherapy, post-chemotherapy, and post-surgery phases of treatment and the effects of chemotherapy were studied. The Trp/ Kyn ratios were significantly lower in the post-epirubicin and cyclophosphamide( EC) chemotherapy phase and post- weekly paclitaxel( wPac) chemotherapy phase than in the pre-chemotherapy phase and post-chemotherapy phase, respectively. There was no significant correlation between the Trp/Kyn ratio in any phase and the response rate. These results suggest that measurement of the Trp/Kyn ratio is not useful for predicting the rate of response to chemotherapy in patients with breast cancer.