Immunohistochemical staining of SOX2 (A and B) and β-catenin (C - F) in colonic adenocarcinoma (400-fold magnification). CC with absence of SOX2 expression (A). Normal gastric mucosa was used as the positive control (insert). Tumours with presence of moderate or strong nuclear protein expression of SOX2 in more than 10% of tumour cells were classified as SOX2 positive (B). Tumour cells with absence (C) or presence (D) of nuclear β-catenin accumulation were classified as β-catenin low or β-catenin high, respectively. Weak (1+) and strong (3+) cytoplasmic staining for β-catenin are shown in (E) and (F), respectively.