Galectin-1, -3, -7 Expressions in Congenital and Acquired Pediatric Cholesteatomas Compared to External Auditory Canal Skin

OBJECTIVES There is a classical distinction based on clinical criteria between acquired and congenital cholesteatomas. To determine if these two types of lesions show different immunohistochemical features, we have studied the expression patterns of three distinctive galectins (animal lectins implied especially in cellular proliferation and apoptosis) in both types of cholesteatomas and compared it to their expression patterns in external auditory canal skin. METHODS Our study is based on nine acquired and eight congenital cholesteatomas, obtained from children during ear surgery. Six specimens of normal adult auditory meatal skin served as control. Specimens were analyzed by immunohistochemistry using monoclonal antibodies with galectin-1 and galectin-3, and a polyclonal antibody with galectin-7. RESULTS We did not observe any differences in the galectin distribution pattern between congenital and acquired pediatric cholesteatomas. Compared to the control group, cholesteatomas present some particular features. There was no expression of galectin-1 and a lower expression of galectin-3 in the epithelium. Furthermore, we observed a preferentially nuclear distribution of galectin-7 in cholesteatomas, whereas it is essentially cytoplasmic in the control group. CONCLUSION The data reported in this study suggest, on the basis of a lesser marked galectin-3 in cholesteatomas epithelium compared with an external auditory canal skin, that an immature keratinocytes population is at the origin of these lesions and that galectin-3 and galectin-7 play a part in the capacity as apoptosis modulators. Our study does not establish a difference in the galectin expressions of congenital and acquired cholesteatomas, but it constitutes however an additional argument in favor of the "undifferentiated" origin of keratinocytes in cholesteatomas.