MKI67 and cancer: Furthermore, the decreased expression of Ki-67 (a well-known prognostic marker for certain types of cancer) [111] after treatment with BMMSC-derived exosomes warrants further exploration of this novel approach as a means of slowing or stopping the excessive cell division and possibly opens the horizon for further experiments investigating the therapeutic potential for BMMSC-derived exosomes in treatment of salivary gland tumors.