Representative indirect immunofluorescence images showing double-stained sections for the detection of the α1 integrin subunit and laminin in a normal colon mucosa (A and B) and a moderately differentiated colon adenocarcinoma specimen (C, D). The α1 subunit (red signal) was observed at the basolateral domain of normal epithelial cells of the lower crypt compartment (LC in panel A and E in panel B) compared to weak signal in the upper compartment (UC, panel A). In CRC, α1 was also localized at the basolateral domain of tumour epithelial cells (E) as well as in the adjacent subepithelial myofibroblasts (MF) (Panels C, D). Basement membrane (arrows) located at the interface between the two tissues was stained with an anti-laminin antibody (green staining). Nuclei were stained with DAPI (blue). Scale bar = 50 μm.