IDO1 and breast cancer: The positive rates of IDO expression in stage I, stage II, or stage III breast cancer were 22.22, 70.45, and 75.00%, respectively (P < 0.05), while the mean MVD levels were 8.27 ± 1.34, 9.52 ± 1.63, and 10.22 ± 2.23, respectively (P < 0.05).