SDC1 and keratoacanthoma: This was supported by following studies showing that in invasive cSCC both syndecan-1 and cadherin E expressions were decreased with the loss of keratinocyte differentiation, especially in the acantholytic areas of tumors where interestingly these molecules were localized to the cytoplasm and not to the cell membrane (63), Indeed, syndecan-1 expression was identified to be discrete between keratoacanthoma and invasive SCC.