Role of pretherapeutic biomarkers in predicting postoperative radiotherapy response in patients with advanced squamous cell carcinoma

Abstract

Purpose : To assess the role of biomarker levels in predicting radiotherapy (RT) response in patients with squamous cell carcinoma of buccal mucosa treated with postoperative RT. Materials and methods : Thirty-one patients with squamous cell carcinoma of buccal mucosa who received postoperative RT were enrolled for the study. Glutathione S -transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD) and catalase activity were analysed from primary tumour and adjacent normal mucosa of the same patients before RT. p53 and p21ras were localized immunohistochemically. Results : Enzyme activation was predicted by comparing the levels of these enzymes in tumour and adjacent normal mucosa. Deactivation of GST, activation of GR, SOD and catalase were associated with poor response to RT. p53 immunoreactivity was associated with failure to respond to RT. Conclusions : These markers may be useful in predicting treatment outcome in patients receiving postoperative RT, although this conclusion requires confirmation in a larger group of patients.