Detection of apoptosis and expression of apoptosis-associated proteins as early predictors of prognosis after irradiation therapy in stage IIIb uterine cervical cancer.

Abstract

We investigated the proportion of apoptotic cells and the expression of apoptosis‐associated proteins after the delivery of the first week of irradiation for stage IIIb uterine cervical cancer. Thirty patients with stage IIIb squamous cell carcinoma of the uterine cervix who received only irradiation therapy were registered in this study. Specimens were obtained before irradiation therapy and at the end of the first week of irradiation. The apoptotic index (AI) of each tissue specimen was calculated by counting the apoptotic cells and expressed as a percentage. Immunohistochemical evaluation for apoptosis‐related proteins, p53, Bcl‐2, Bax, caspase‐1 and caspase‐3 was also performed. The AI was 0.8±0.9% (mean±SD) before irradiation and 1.7±1.3% at the end of the first week of irradiation. We observed that the patients who survived more than 5 years had AI levels of 2.1±1.3% at the end of their first week of therapy. This rate was significantly higher than the rate of 1.1±0.8% (P=0.02) of the patients who died within 5 years. When the cut‐off value of the AI was set at 1.7%, the sensitivity, specificity, positive predictive value, and negative predictive value for the prediction of patients' prognosis after irradiation therapy were 73.4%, 72.4%, 82.4%, and 61.5%, respectively. In 17 of the AI‐positive cases, expressions of Bax (P=0.006), caspase‐1 (P=0.045), and caspase‐3 (P=0.013) at the end of the first week were significantly higher than before irradiation. The proportion of apoptotic cells and the expression of apoptosis‐associated proteins, Bax, caspase‐1, and caspase‐3, at the end of the first week of irradiation could be useful predictors of the prognosis in stage IIIb squamous cell carcinoma of the uterine cervix treated by irradiation therapy.