Galectin-7 as a Marker of Cholesteatoma Residue and Its Detection During Surgery by an Immunofluorescent Method—A Preliminary Study

Abstract

To visualize the distribution of galectin-7 in middle ear cholesteatomas using an immunofluorescent method and to establish whether galectin-7 can be used as a marker of cholesteatoma residue at the time of operation. Middle ear cholesteatomas were obtained at surgery from 30 patients. Samples were frozen and preserved in a freezer until histological study. After serial sectioning with a cryostat, 2 of the specimens were processed with primary antibody and Zenon rabbit immunoglobulin G labeling kits. After sufficient reaction time, the samples were observed using a confocal laser microscope. In the remaining 28 specimens, the cholesteatoma was treated as 1 block and stained with the same solution. It was then observed using a fluorescent stereomicroscope. Confocal microscopic analyses showed that galectin-7 was distributed in the cholesteatoma matrix. Because this area strongly stained green, it was easily recognized using a confocal laser microscope. In the stereomicroscopic study using the 1-block specimen in which the cholesteatoma was processed together with the surrounding granulation and mucosal tissue, only the matrix and overlying debris was yellow-green in response to excitation by light; the surrounding granulation and mucosal tissues did not respond in 7 specimens. In the remaining 21 specimens, the whole sample was composed of cholesteatoma and responded well to excitation by light. These findings suggest that galectin-7 might be a useful marker of cholesteatoma residue that can be visualized using this immunofluorescent method. Because residual cholesteatoma matrix is considered to be one of the main causes of cholesteatoma recurrence, staining with galectin-7 at the time of operation would be a promising way to facilitate complete removal of the residue.