Prediction of radiosensitivity in human esophageal squamous cell carcinomas with heme oxygenase-1: A clinicopathological and immunohistochemical study

The lack of an accurate system to predict the response to radiotherapy for individual cancer lesions remains a major clinical problem. The aim of this study was to establish whether heme oxygenase-1 (HO-1) may be useful in predicting radiosensitivity of esophageal cancers. We evaluated biopsy specimens from 13 esophageal squamous cell cancer patients. Of these, 8 patients had tumors responding to radiotherapy, and the remainder were considered radioresistant. Expression of HO-1 was assayed using a standard immunoperoxidase technique. Clinicopathological parameters were also analyzed as factors potentially contributing to radiosensitivity. Seven of 13 patients (53.8%) showed cytoplasmic staining for HO-1 in cancer tissues. The local treatment failure rate was 0% for HO-1 positive patients, as opposed to 83.3% for HO-1-negative patients (p=0.012). In contrast, tumor size, stage, and histologic grade were not significantly different between radiotherapy responders and non-responders to radiation therapy. No relationship was observed between HO-1 expression and clinicopathologic features. The results of the current study suggest that expression of HO-1 may be a useful indicator of radiosensitivity for esophageal cancer patients.