MMP14 and cancer: Although the results of gene expression profiling of MMPs (Table 1, Table 3, Table 5 and Figure 1, Figure 2 and Figure 3) and some other reports have shown that MT1-MMP expression increases in HNSCC cases and plays an important role in the formation of functional invadopodia during cancer progression [8,106,107,108,109], there are still significant technical problems that need to be solved for clinical assessment of cancer progression targeting invadopodia.