Figure 1

Abi1 expression analyses. A, in silico gene expression analysis using the GeneSapiens database [31] shows no significant differences in Abi1 gene expression among adenocarcinomas of gastrointestinal origin. B, representative microphotographs of Abi1 immunohistochemistry at the invasive margin of expanding (I) and infiltrating (II) CRC. Tumour cell budding in (II) is indicated by arrows. Greater magnification (III) shows strong Abi1 expression in cytoplasm and podia-like cellular protrusions (arrows). Immunofluorescence staining for phosphorylated Abi1 (p435) shows strong positivity in dissociating tumour cells at the invasive margin (IV). C, statistical evaluation of Abi1 IHC staining scores shows significant higher expression scores at the leading edge compared to tumour centre (I) as well as in tumours with infiltrating growth and high-grade tumour cell budding compared to tumours with expanding growth and low-grade budding (II). Moreover, Abi1 expression score is significantly associated with lymph and/or blood vessel infiltration by the tumour (III). Quantification of staining intensities (IV) shows stronger cytoplasmic as well as nuclear positivity for phosphorylated Abi1 (pY435) at the invasive margin compared to the tumour centre. IHC, immunohistochemistry; exp, expanding growth; inf, infiltrating growth; 0–9, 10: intensity of tumour cell budding in an x250 visual field. Scale bars as indicated. *p < 0.05; ***p < 0.001.