MMP2 and cholesteatoma: In an experimental study with gerbils (Mongolian squirrel) (published in 2002), they tested the MMP2 topical inhibitor, Ilomostat, observing whether or not there is any relation with the formation of atelectasis on the tympanic membrane of these animals, and no statistical difference was observed between the group that received the drug for eight weeks (6 animals) and the control group (7 animals); it could not be stated for sure that the same thing could correlate to human cholesteatomas.