Background: The receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is a human tumor-associated antigen that has been considered to play a crucial role in tumor progression by enabling cancer cells to evade immune surveillance. The present study aimed to evaluate the clinical significance of RCAS1 expression in mobile tongue squamous cell carcinoma (SCC).
Material/Methods: RCAS1 protein expression was assessed immunohistochemically on 49 mobile tongue SCC tissue samples obtained from an equal number of patients and was statistically analyzed with clinicopathological characteristics and overall and disease-free patients’ survival.
Results: Enhanced RCAS1 expression was significantly associated with reduced depth of invasion (p=0.0069), low mitotic index (p=0.0251) and no evidence of muscular invasion (p=0.0098). A borderline association between RCAS1 expression and stromal inflammatory reaction was also noted (p=0.0660). RCAS1 expression was not associated with overall and disease-free survival.
Conclusions: Our data support evidence for possible implication of RCAS1 at the early stage of tumor progression in mobile tongue SCC, whereas the survival prediction using RCAS1 expression as a clinical marker seems uncertain for this type of malignancy.

Keywords: Keratins - metabolism, Disease Progression, Carcinoma, Squamous Cell - pathology, Antigens, Neoplasm - metabolism, Aged, 80 and over, Tongue Neoplasms - pathology