Prognostic significance of apoptosis and associated factors in oral squamous cell carcinoma

Tumour progression is characterised by an imbalance between cell proliferat ion and apoptosis. The aim of our study was to estimate the importance of p roliferation and apoptosis associated parameters in primary squamous cell c arcinomas (SCCs) of the oral cavity and oropharynx. For determination of ap optosis, the enzymatic labelling of DNA fragmentation with a terminal trans ferase reaction was used in 156 tissue samples of 107 patients, including c orresponding lymph-node metastases in nine cases. P53, bcl-2, and Ki-67 wer e determined immunohistologically. P53 was detectable in 50.5% of the cases . Positive staining was associated significantly with decreased apoptosis ( P<0.003). Bcl-2 was upregulated in 31.8% of the cases depending on the tumo ur grading (P<0.001) and correlated negatively with apoptosis (P<0.001). Pr oliferation (P<0.006) and apoptosis (P<0.03) were enhanced in larger rumour s, though a direct correlation between these two parameters was not proven. Nevertheless, in contrast to the conventional tumour staging and grading, neither the expression of p53 or bcl-2 nor the apoptosis or Ki-67 measureme nts were able to predict survival or recurrence-free survival of the patien ts suffering from a SCC in the oral cavity or oropharynx. Our observations suggest that the function of wild-type p53 to induce apoptosis is lost in a t least half of the SCCs under study and that the physiological function of bcl-2 as potent inhibitor of apoptosis is widely preserved in oral SCC.