In ApoE-deficient mice given a Western diet, Freudenberger et al. demonstrated that long-term treatment with MPA alone or MPA + E2 increased arterial thrombosis following photochemical injury of the right carotid artery, whereas another synthetic progestin, norethisterone acetate, did not affect arterial thrombosis [23,27]. The gene discussed is APOE; the disease is Venous thrombosis.