IGFBP3 and head and neck squamous cell carcinoma: Further mechanistic studies revealed that IGFBP-3 negatively regulates EMT phenotypes of NSCLC and HNSCC cells and suppresses their migratory activities in an IGF-independent manner by directly binding to vimentin and inducing its degradation through the E3 ligase FBXL14-mediated proteasome machinery.