Appearance of bax protein after preoperative chemoradiotherapy is a prognostic factor in maxillary cancer

The prognosis for maxillary squamous cell carcinoma (SCC) remains poor, despite advances in combination therapy. Combined treatment with anticancer drugs and radiation therapy is aimed at inducing apoptosis. As apoptosis is regulated by several proteins, we investigated the expression of p53, Bax and Bcl-2 in maxillary SCC before treatment and after preoperative chemoradiotherapy using an immunohistochemical approach. Furthermore, apoptotic cells were visualized using an in situ apoptosis detection kit and the apoptosis index (AI) was defined as the number of positive cancer cells per 1,000 cancer cells. Expression of p53 and Bcl-2 and the Al in 23 maxillary SCCs were not associated with tumor size, lymph node metastasis, clinical stage, frequency of recurrence or 5-year survival rate either before treatment or after preoperative chemoradiotherapy. Bax expression before treatment was not correlated with any clinicopathological factors before treatment. However, no patients in the Bax-positive group (11/22 cases) after preoperative chemoradiotherapy had recurrence of maxillary SCC and all were alive after 5 years, while the 5-year survival rate was 34.1% in Bax-negative patients. These results suggest that the appearance of the Bax protein after preoperative chemoradiotherapy is a significant prognostic marker for maxillary SCC.