The expression of syndecan-1 is preferentially reduced compared with that of E-cadherin in acantholytic squamous cell carcinoma

Background: Syndecan-1 and E-cadherin are cell adhesion molecules which are expressed primarily on the surface of adult epithelial cells. They appear to be co-regulated and may act in concert to stabilize the epithelium. Loss of expression of both E-cadherin and syndecan-1 is seen in malignant trans formation and invasion. Methods: Thirteen cutaneous biopsies of acantholytic squamous cell carcinom a ISCC) were examined for coexpression of E-cadherin and syndecan-1. Results: Interestingly, immunoreactivity for E-cadherin was increased in th e in situ component while immunoreactivity for syndecan-1 was similar to th at seen in normal skin. Conversely, in invasive SCC the expression of these two adhesion molecules was very similar. Both diminished with decreasing c ell differentiation, as well as in the acantholytic areas where both molecu les exhibited increasing cytosolic staining rather than cell membrane stain ing. Conclusions: Our results suggest that it is likely E-cadherin and syndecan- 1 act in concert to stabilize the epithelium and that the loss or decreased expression of both of these adhesion molecules is associated with malignan t transformation.