Expression of hypoxic-inducible factor 1alpha predicts metastasis-free survival after radiation therapy alone in stage IIIB cervical squamous cell carcinoma.

Abstract

Hypoxia-inducible factor-1alpha (HIF-1alpha) is an intrinsic marker of tumor hypoxia. It has been considered that the hypoxic status reduces radiosensitivity, but the role of HIF-1alpha in advanced cervical carcinoma is still unclear. The objective of this study was to clarify the impact of HIF-1alpha, human papillomavirus (HPV), and other molecular factors, such as p53, bax, bcl-2, and their correlations on the outcome of patients with Stage IIIB cervical carcinoma in radiation therapy. We analyzed 38 patients with FIGO Stage IIIB squamous cell carcinoma of the cervix treated with radiation therapy alone. All patients received the combination therapy of external beam irradiation and low-dose-rate intracavity brachytherapy. The tumor expressions of HIF-1alpha, p53, bax, and bcl-2 were examined by immunohistochemical staining of the pretreatment paraffin embedded specimens. HPV infection was also detected by polymerase chain reaction. The effects of these parameters on clinical outcomes were analyzed by univariate analysis. Of 38 patients, high expression of HIF-1alpha, p53, bax, and bcl-2 were seen in 17 (45%), 22 (58%), 15 (39%), and 15 (39%) patients, respectively, and 28 patients (74%) showed positive infection with HPV. There was a significant positive correlation between high HIF-1alpha expression and disease recurrence (p < 0.05). Furthermore, HIF-1alpha had a significant correlation with the recurrence-free survival rate (p = 0.04). No statistical correlation was noted between high HIF-1alpha expression and the local control rate (p = 0.17), whereas the HIF-1alpha status predicted distant metastasis with strong significance (p = 0.03). Conversely, other factors demonstrated no impact on the clinical outcome. The present results suggest that HIF-1alpha is an important prognostic factor, especially for predicting future metastasis after radiation therapy for patients with Stage IIIB squamous cell carcinoma of the cervix.