Calretinin is a
calcium-binding protein with a possible role as a
calcium buffer,
calcium-sensor, or regulator of apoptosis.
Calretinin is expressed in neural tissue, is a specific marker of mesothelial cells, and has been demonstrated in the odontogenic epithelium during odontogenesis in rat molar tooth germs. Moreover, it has been found to be expressed in a high proportion of solid, unicystic, and multicystic
ameloblastomas, whereas, on the contrary, no positive staining has been found in odontogenic
keratocysts, residual
cysts, and
dentigerous cysts. The purpose of this study was to evaluate
calretinin expression in
radicular cysts,
follicular cysts, orthokeratinized
keratocysts, and parakeratinized
keratocysts. A total of 70
odontogenic cysts, 24
radicular cysts, 24
follicular cysts, and 22 odontogenic
keratocysts (10 orthokeratinized
keratocysts, 12 parakeratinized
keratocysts) were evaluated. All the
radicular cysts,
follicular cysts, and orthokeratinized
keratocysts were negative. However in 8 of 12 parakeratinized
keratocysts, there was a positivity to
calretinin in the parabasal-intermediate layers of the
cyst epithelium. This positivity to
calretinin in the parabasal layers in parakeratinized
keratocysts, similar to that found for other markers like
PCNA and p53, could point to an abnormal control of the cell cycle and could help to explain the differences in the clinical and pathologic behavior of odontogenic
keratocysts, in particular the differences found between orthokeratinized
keratocysts and parakeratinized
keratocysts.