In terms of predictive molecular factors for everolimus treatment efficacy, a recent study involving 58 patients with well-differentiated panNENs demonstrated that higher intra-tumoral expression of acetyl-CoA carboxylase 1 (ACC1), a key enzyme in fatty acid biosynthesis, is significantly associated with decreased PFS, suggesting the importance of tumor lipid metabolism in everolimus treatment [237]. This evidence concerns the gene ACACA and neoplasm.