The strongly positive correlation between the median ADAM9 IRS and distinct grades of OSCC differentiation may be involved in mediating the transition from the well differentiated OSCC to the moderately differentiated OSCC, and then to the poorly differentiated OSCC, probably resulting in enhanced aggressiveness of oral cancer cells, as proposed by Peduto et al. [36] for a crucial role of ADAM9 expression in the transition from the well differentiated to the poorly differentiated prostate cancer. Here, ADAM9 is linked to lip and oral cavity carcinoma.