Immunohistochemical expression of Snail1 protein in colorectal adenocarcinoma samples and its prognostic activity in Caucasian patients

Introduction
The current study investigated the expression of Snail1 protein in colon adenocarcinoma samples to assess its prognostic significance by correlating its expression with the clinicopathological variables and survival of Caucasian patients.

Aim: To investigate the clinicopathological and prognostic roles of Snail1 expression, the immunohistochemical analysis was performed in colon tumour tissues and adjacent non- pathological mucosa.

Material and methods
It should be noted that only trace expression of this protein was revealed in adjacent non-tumour colorectal mucosa, whereas the high expression was demonstrated in well differentiated, moderately differentiated, and poorly differentiated tumours.

Results
The Kaplan-Meier survival analysis showed that the overall survival rate in the group of patients with a low expression level of Snail1 was significantly longer than that for patients with a moderate or strong level of Snail1 immunoreactivity (p < 0.001). The 5-year overall survival for patients with a low, moderate, or strong level of Snail1 immunoexpression was 100%, 25.7%, and 2%, respectively. The Snail1-moderate patients had an average survival time of 44.886 months (95% CI: 40.855–48.916), whereas the Snail1-strong expression groups had an average survival time of 21.706 (95% CI: 17.863–25.549). The statistical analysis revealed that the level of the Snail1 immunohistochemical reactivity was correlated with the grade of the histological differentiation. A multivariate analysis demonstrated that the grade of tumour differentiation (HR = 2.150; 95% CI: 1.380–3.349, p = 0.001) and Snail1 expression (HR = 3.901; 95% CI: 2.436–6.247, p < 0.001) were the independent risk factors for worse survival.

Conclusions
In colon adenocarcinoma patients, the expression of Snail1 may act as the independent risk factors for worse survival.