Results in the present study showed that treatment with the semisynthetic δ-tocotrienol oxazine derivative, compound 44, was effective in blocking +SA mammary tumor cell compensatory response to hypoxia, by suppressing HIF-1α expression, as well as the activation of Akt/mTOR and MAPK pathways, and VEGF production. The gene discussed is HIF1A; the disease is breast cancer.