Twist and snai1 expression in pharyngeal squamous cell carcinoma stroma is related to cancer progression

Background: Epithelial-mesenchymal transition (EMT) is a crucial process in tumorigenesis since tumor cells attain fibroblast-like features enabling them to invade to surrounding tissue. Two transcription factors, TWIST and SNAI1, are fundamental in regulating EMT. Methods: Immunohistochemistry was used to study the expression of TWIST and SNAI1 in 109 pharyngeal squamous cell carcinomas. Results: Tumors with intense stromal staining of TWIST relapsed more frequently (p = 0.04). Tumors with both positive TWIST and SNAI1 immunoreactivity in the stroma were at least Stage II (p = 0.05) and located more often in hypopharynx (p = 0.035). Tumors with negative immunostaining of TWIST and SNAI1 in the stromal compartment were smaller (T1-2) (p = 0.008), less advanced (SI-II) (p = 0.031) and located more often in the oropharynx (p = 0.007). Patients with negative SNAI1 and TWIST immunostaining in tumor stroma had a better 5-year disease-specific and overall survival (p = 0.037 and p = 0.014 respectively). Conclusion: TWIST and SNAI1 expression in stromal cells is associated with clinical and histopathological characteristics that indicate progressive disease. Negative expression of these EMT-promoting transcription factors predicts a better outcome.