Propanoate has been shown to inhibit tumor cell proliferation and promote apoptosis in different cancer cell types [35–37]; one possible explanation for our observation may be related to reduced expression of free fatty acid receptor 2 (FFAR2, also known as GPR43)—a receptor for which propanoate is the most potent ligand [38]—leading to an unproductive pool of propanoate. This evidence concerns the gene FFAR2 and cancer.