Similarly, syngeneic breast cancers in ApoE-/-, LDLR-/-, and APOE3+/+ mice, which are all models of hyperlipidemia, demonstrated increased growth compared to controls; ER-negative tumors in ApoE-/-and LDLR-/- mice, and ER-positive tumors in APOE3+/+ (181–183). This evidence concerns the gene LDLR and breast cancer.