Disclosed herein are compositions and methods for treating or preventing certain cancers in a subject. In certain embodiments such compositions and methods generally relate to the use of G-coupled protein receptor 40 (GPR40) agonists to inhibit the growth or induce apoptosis of certain cancer cells. The compositions and related methods disclosed herein may be used to treat subjects affected by cancers, such as melanoma, medullary thyroid carcinoma, malignant peripheral nerve sheath tumors and neuroblastoma, and to reduce the incidence of metastases in such affected subjects.