Based on the immunoblot results in which we demonstrated high expression levels of ERRα and of PGC1α, as well as high expression levels of ERbB2/HER2, representing a tyrosine kinase receptor highly implicated in the control of various metabolic processes, we analyzed the metabolic profile of all breast cancer cell lines after treatment with mevalonate or cholesterol for 48 h, by using a Seahorse XFe96 analyzer. The gene discussed is ERBB2; the disease is breast cancer.