DDIT4 and breast cancer: Previously, TRIB3 was shown to be induced by hypoxia (0.1–0.5% O2) in breast cancer cells [13] and in rat pulmonary artery smooth muscle cells (5% O2) [16], Expression of Ddit4 and Gadd45a were previously shown to be increased under hypoxia and oxidative stress [62, 64, 88].