Figure 1.

Schematic view of the colonic epithelium showing the differential expression of integrin α6β4 forms in the normal mucosa and in tumours. Under normal conditions, the α6A subunit is located in the proliferative cells of the gland while α6B is confined to the quiescent upper gland and surface epithelial cells.⁵ In colorectal tumours, total α6β4 expression increases as its α6Aβ4 form.^{5 8}