Analysis of epidermal growth factor receptor in histopathologically tumor-free surgical margins in patients with oral squamous cell carcinoma
Oral squamous cell carcinoma (OSCC) is the most common oral malignancy. The prevalence of OSCC has been reported in more than 90% of all oral cancers. The main treatment of OSCC is complete removal of the tumor. Nevertheless, treatment is not always successful. Approximately 40% of treatment failure rate is seen in patients with OSCC, the most common cause of which is local or regional lymph node recurrence. Even in tumor-free surgical margins, a 30% recurrence rate has been reported. Molecular changes that might indicate early tumor development are seen in normal surgical margins of tumors in the oropharynx and larynx regions. Epidermal growth factor receptor (EGFR), a receptor of tyrosine kinase of ErbB family that is found in tumor lesions, is associated with tumor invasion, increased metastasis to cervical lymph nodes and lower histological differentiation of tumor in OSCC. The existence of EGFR in histopathologically free tumor margins has not been investigated. The purpose of this study was to assess EGFR expression in histopathologically tumor-free margins. A total of 40 paraffin-embedded tissue blocks related to OSCC were obtained from the Pathology Department of Dental School, Tabriz, Iran. All the samples included histologically tumor-free margins and were analyzed by immunohistochemistry for EGFR. Fisher exact test with 95% confidential level was used to analyze data. Strong EGFR staining in the membrane of tumor cells was seen in 30 of 40 (75%) tumor tissues and 4 of 40 (10%) histopathologically tumor-free margins. This study confirmed that the assessment of tumor-free surgical margins by conventional histopathologic examination is not sufficient and detection of EGFR may identify patients who are at a high risk for tumor recurrence and can benefit from anti-EGFR treatment.
Key words: Epidermal growth factor receptor (EGFR), immunohistochemistry, oral squamous cell carcinoma, surgical margin.