The emerging role of fatty acid binding protein 5 (FABP5) in cancers

•Fatty acid binding protein 5 (FABP5) is a key regulator of cell metabolism and growth that is overexpressed in cancers.•FABP5 facilitates the activation of transcriptional factors that increase proteins key in cancer progression.•FABP5 overexpression in tumours correlates with patient prognosis across many cancers.•Inhibition of FABP5 reduces tumour growth and metastasis and may represent a novel therapeutic strategy. Fatty acid binding protein 5 (FABP5, or epidermal FABP) is an intracellular chaperone of fatty acid molecules that regulates lipid metabolism and cell growth. In patient-derived tumours, FABP5 expression is increased up to tenfold, often co-expressed with other cancer-related proteins. High tumoral FABP5 expression is associated with poor prognosis. FABP5 activates transcription factors (TFs) leading to increased expression of proteins involved in tumorigenesis. Genetic and pharmacological preclinical studies show that inhibiting FABP5 reduces protumoral markers, whereas elevation of FABP5 promotes tumour growth and spread. Thus, FABP5 might be a valid target for novel therapeutics. The evidence base is currently strongest for liver, prostate, breast, and brain cancers, and squamous cell carcinoma (SCC), which could represent relevant patient populations for any drug discovery programme.