Figure 4.

photomicrograph A) Immunostaining showing CK7 positivity in tumour cell groups. B): Immunostaining showing CEA positivity in tumour cell groups. C): Immunostaining showing CK20 negativity in tumour cell groups. D): Immunostaining for CDX2. There is positive staining in normal colonic mucosa (single arrow) whereas the tumour beneath the mucosa stains negative (two arrows).