Prognostička vrijednost izraženosti koštanoga morfogenetskoga proteina 6 u planocelularnim karcinomima usne šupljine [Prognostic significance of bone morphogenetic protein 6 (BMP6) expression in oral squamous cell carcinoma]

Introduction: Bone morphogenetic proteins, BMPs, are growth and differentiation factors, originally isolated as molecules which in vivo stimulate ectopic bone and cartilage formation. Overexpression of BMP6 has been shown in various malignant tumors. However, the prognostic significance of its expression in oral squamous cell carcinoma (OSCC) is still unknown. Immunohistochemistry and semiquantitative analyses were performed in order to determine the level of BMP6 in OSCC, thus correlating it with clinical and histological prognostic parameters, disease recurrence and survival. Patients and methods: The study included 120 patients with clinically T1-3N0 OSCC,who were treated primary surgically, between January 1, 2003 and December 31, 2008. Results: There were 99 (82,5%) males and 21 (17,5%) females, with an average age of 59 years. Five-year disease-specific survival rate for the whole cohort was 79,4%. Twenty patients had died during the follow-up, while 100 patients were censored. Patients with tumors smaller than 2,1 cm determined histologically showed higher incidence of strong BMP6 expression. No statistically significant corellation was detected between the level of BMP6 expression and other clinico-pathological factors. Similarly, the expression of BMP6 was neither associated with disease recurrence nor was it associated with patient's survival. Conclusions: Accordingly, routine analysis of BMP6 expression for predicting the biological behaviour of OSCC is not justified. The level of BMP6 expression cannot be considered as a prognostic factor in OSCC. In multivarite model, positive surgical margin, moderate tumor cell differentiation and metastatic cervical lymph nodes located at levels 4 and/or 5 were independent predictors of survival.