Juan C de Vicente1,2, Ignacio Peña1, Juan P Rodrigo3,2, Tania Rodríguez-Santamarta1, Paloma Lequerica-Fernández4, Laura Suárez-Fernández3, Eva Allonca3, Juana M García-Pedrero3,2. 1. Department of Oral and Maxillofacial Surgery, Hospital Universitario Central de Asturias (HUCA), Oviedo, Asturias, Spain. 2. Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Hospital Universitario Central de Asturias, Oviedo, Asturias, CIBERONC ISCIII Spain. 3. Department of Otolaryngology, Hospital Universitario Central de Asturias (HUCA), Oviedo, Asturias, Spain. 4. Department of Biochemistry, Hospital Universitario Central de Asturias (HUCA), Oviedo, Asturias, Spain.
Abstract
BACKGROUND: The purpose of this study was to investigate the clinical relevance of phosphorylated ribosomal protein S6 (p-S6), a surrogate marker of mammalian target of rapamycin (mTOR) activation, and p21 in a series of 125 patients with oral squamous cell carcinomas (OSCCs). METHODS: Immunohistochemical analysis was performed to ascertain the phosphorylation status of p-S6 at Ser235/236 and Ser240/244, p21, and p53 protein expression. RESULTS: Expression of phosphorylated S6 protein on either serine 235/236 or serine 240/244 was detected in 83% and 88% tumors, respectively, and both of them were inversely and significantly correlated with the tumor size and local infiltration. Positive p21 expression was found in 91.5% of the cases, and was inversely correlated with tumor size. In OSCC, p21 expression correlates with p-S6 levels, a surrogate marker of mTOR activation, independently of p53 status. CONCLUSION: Expression of both p21 and p-S6 was found to inversely associate with tumor size but not survival outcomes in patients with OSCC.
BACKGROUND: The purpose of this study was to investigate the clinical relevance of phosphorylated ribosomal protein S6 (p-S6), a surrogate marker of mammalian target of rapamycin (mTOR) activation, and p21 in a series of 125 patients with oral squamous cell carcinomas (OSCCs). METHODS: Immunohistochemical analysis was performed to ascertain the phosphorylation status of p-S6 at Ser235/236 and Ser240/244, p21, and p53 protein expression. RESULTS: Expression of phosphorylated S6 protein on either serine 235/236 or serine 240/244 was detected in 83% and 88% tumors, respectively, and both of them were inversely and significantly correlated with the tumor size and local infiltration. Positive p21 expression was found in 91.5% of the cases, and was inversely correlated with tumor size. In OSCC, p21 expression correlates with p-S6 levels, a surrogate marker of mTOR activation, independently of p53 status. CONCLUSION: Expression of both p21 and p-S6 was found to inversely associate with tumor size but not survival outcomes in patients with OSCC.