SPHK1 and head and neck squamous cell carcinoma: Masood et al. [71] used the GNR-SphK siRNA nanocomposite [GNRs loaded by short interfering RNA (siRNA) targeting the anti-apoptotic sphingosine kinase (SphK1) gene] to induce radiation sensitization in head and neck squamous cell carcinoma (HNSCC) tumor in mice.