FASN and breast cancer: Previous studies have shown fatty acid synthesis is elevated and critical for breast tumors growing in the brain and the enzyme responsible for de novo lipid synthesis, fatty acid synthase (FASN) is required for growth and survival of these tumors (Breast Cancer Brain Metastases Rely, 2021; Ferraro et al., 2021; Menendez and Lupu, 2022; Cheng et al., 2023).