Tumor progression and chemoradiosensitivity in relation to the expression of apoptosis related proteins in esophageal squamous cell carcinoma

Abstract

4588 To study apoptosis related protein expression and their impact on patient’s survival time and sensitivity to postoperative chemoradiotherapy (CRT), we examined the expression of RB, mutant p53, MDM2 and Bax proteins using immunohistochemistry in 115 (CRT; 42) surgically resected esophageal squamous cell carcinoma (ESCC). We also investigated the survivin mRNA expression with quantitative analysis by real-time RT-PCR in 57 (CRT; 30) patients with ESCC. CRT contained 40–60 Gy radiation and continuous infusion of 5-FU (300mg/sqm, day1–5qw). Expression of RB, mutant p53, MDM2, Bax proteins and survivin mRNA were detected in 65%, 46%, 33%, 37% and 32% of patients, respectively. Patients with RB(+), MDM2(-), Bax(+) or survivin(-) tumor had significantly better survival rates than those with RB(-), MDM2(+), Bax(-) or survivin(+) tumor, respectively. However, there was no significant difference in survival between patients with and without mutant p53 expression. In patients not treated with CRT, those with RB(+) or survivin(-) tumor survived significantly longer than those with RB(-) or survivin(+) tumor, respectively. In patients treated with CRT, the expression of Bax protein and survivin mRNA was prognostic indicator. The 5-year survival rates of patients with Bax(+) and survivin(-) tumors were 65% and 39%, significantly superior to 21% and 0% of those with Bax(-) and survivin(+) tumors (P<0.05 and P<0.01, respectively). These results indicate that the expression levels of apoptosis related proteins are important for predicting the prognosis of ESCC patients. Furthermore, CRT may be effective in patients with Bax(+) or survivin(-) tumors. Further investigations are required for clarifying the relationship between the efficacy of postoperative CRT and apoptosis promoting status of ESCC. No significant financial relationships to disclose.