OLFM4 and neoplasm: Similarly, Marimuthu et al. [151] confirm the higher abundance of some markers in the secretome derived from HNSCC tumour cells, including olfactomedin-4, OLFM4, hepatocyte growth factor activator, HGFA, insulin-like growth factor binding protein 3, IGFBP3, and opioid growth factor receptor, OGFR, reaching 70–75% of the studied cases.