Bax expression as a prognostic marker of postoperative chemoradiotherapy for patients with esophageal cancer

Postoperative chemoradiotherapy was introduced to improve the survival of patients with esophageal squamous cell carcinoma (ESCC). However, considerable number of patients still die of cancer recurrence despite curative operation plus chemoradiotherapy. This indicates that some ESCCs are chemoradio-resistant. To prevent unnecessary treatment and to improve the effect of post-operative adjuvant therapy, it seems to be important to investigate biological markers of chemoradio-sensitivity in ESCC. Loss of Bax expression has been reported to be associated with poor response to chemotherapy in breast cancer, and Bax promotes apoptosis in cells. Abnormal expression of Bax may play an important role in chemoradio-sensitivity in malignant tumors. In this study, we retrospectively investigated the prognostic significance of the expressions of Bax and p53 in patients with ESCC. Immunoreactivities of Bax and p53 were evaluated in 141 surgically resected ESCC by using monoclonal antibodies. Prognoses of 141 patients with or without postoperative chemoradiotherapy were compared among groups with high and low expressions of Bax or p53. High immunoreactivities of Bax and p53 were detected in 49 cases (33.1%) and in 70 cases (47.3%), respectively. Loss of Bax expression was detected more frequently in p53-positive tumors. Bax expression correlated with favorable prognosis (P=0.016) in 57 patients with postoperative chemoradiotherapy. However, in 84 patients without adjuvant therapy, the prognostic significance of Bax was minimal. Moreover, in patients with or without postoperative chemoradiotherapy, p53 expression did not correlate with the prognosis. Bax expression may be a good marker for chemoradio-sensitivity in patients with ESCC.