The ΔN isoforms of p63 may also serve as stem cell markers in a variety of epithelial cell types, including endometrium [30], cervix [31], breast [32], prostate [33], and in
stratified squamous epithelium [21,34].
Anatomically, the mucosa of the head and neck can be divided into a layer of
stratified squamous epithelium and an underlying connective tissue layer known as the lamina propria (Table 2).
Type I mucosal surfaces line the upper rectum and consist of a single layer of tightly joined, simple columnar epithelium, while type II mucosal surfaces line the lower rectum and anus and consist of multiple layers of
stratified squamous epithelium.