Thermally Abused Frying Oil Potentiates Metastasis to Lung in a Murine Model of Late-Stage Breast Cancer

Deep-frying is a popular form of food preparation used globally and throughout in the United States. Each time dietary oils are heated to deep-frying temperatures, they undergo chemical alterations that result in a new matrix of lipid structures. These lipid products include triglyceride dimers, polymers, oxidized triglycerides, and cyclic monomers, which raises nutritional concerns about associations between these lipid products and heightened health risks. Reports of associations between thermally abused frying oil and deleterious health outcomes currently exist, yet there is little information concerning the effects of thermally abused frying oil consumption and the progression of breast cancer. This study used a late-stage breast cancer murine model and in vivo bioluminescent imaging to monitor progression of metastasis of 4T1 tumor cells in animals consuming fresh soybean oil (SBO) and a thermally abused frying oil (TAFO). Bioluminescent and histologic examinations demonstrated that TAFO consumption resulted in a marked increase of metastatic lung tumor formation compared to SBO consumption. Further, in animals consuming the TAFO treatment diet, metastatic tumors in the lung displayed a 1.4-fold increase in the Ki-67 marker of cellular proliferation and RNA-sequencing analysis of the hepatic tissue revealed a dietary-induced modulation of gene expression in the liver.