Prognostic value of the density of Wilms tumour protein 1 (WT-1) positive microvessels in stage IIA colorectal cancer

Stage IIA colorectal cancer (CRC) displays 5-year survival rate around 85%; hence it is not currently submitted to any adjuvant treatment. However a percentage of stage IIA CRCs undergoes disease progression and would benefit from additional therapies. In the aim to investigate whether Wilms Tumor-1 (WT-1) expression might represent a prognostic factor in stage IIA CRC, we analyzed its immunohistochemical expression in 90 stage IIA CRCs divided into two groups according to the evidence of disease progression. While WT-1 staining in the neoplastic cells was not significantly associated with any of the clinico-pathological parameters, the density of intra-tumoral microvessels positive for WT-1 (WT-1 MVD) was significantly higher in stage IIA CRCs characterized by disease progression compared to non-recurring tumours and it was significantly and independently associated with shorter disease-free survival. This study is the first to demonstrate that WT-1 MVD may be useful to discriminate high risk patients with stage IIA CRCs and who may benefit from adjuvant treatment. WT-1 expression in the tumor vessels, but not in the vessels of normal colorectal mucosa, suggests its possible role in tumor neo-angiogenesis and it may represent a target for novel anti-angiogenic therapies in stage IIA CRC at high risk of progression.