Expression and alteration of p53 and p21(waf1/cip1) influence the sensitivity of chemoradiation therapy for esophageal cancer

BACKGROUND/AIMS: In vitro analyses have been demonstrated that wild type p53 and p21(waf1/cip1) proteins regulate cellular proliferation and sensitivity of anticancer agents, however, the roles of p53 and p21(waf1/cip1) expression on the response to the chemoradiation therapy for human esophageal squamous cell cancer have not been investigated. METHODOLOGY: With an immunohistochemical method using specimens before and after the chemoradiation therapy, we investigate in this report the influence of the p53 and p21(waf1/cip1) expression on the chemoradiation therapy response or alteration of these protein expressions by chemoradiation therapy in thirteen esophageal squamous cell cancer patients who received our recently developed chemoradiation therapy. RESULTS: In the biopsy specimens before the chemoradiation therapy, 82% of the responders and 71% of patients with down T-classification had either a p53-/p21+ or p53+/p21+ phenotype. Eighty two percent and 46% of the cases with these two phenotypes showed complete or partial response and down T-classification, respectively. After the chemoradiation therapy, 73% of the responders and 71% of the patients with down T-classification had either a p53-/p21+ or p53+/p21+ phenotype. Eighty eight percent and 56% of the cases with these two phenotypes showed complete or partial response and down T-classification, respectively. Comparative analysis before and after the chemoradiation therapy revealed that four patients had an alteration of p53 and p21(waf1/cip1) expression in association with the therapeutic response. CONCLUSIONS: These results suggest that wild type p53 or p21(waf1/cip1) expression relates with and can be altered by the chemoradiation therapy, which could influence the therapeutic efficacy.