Intraoperative Molecular Margin Analysis in Head and Neck Cancer

Abstract

Background: Tumor-specific molecular alterations in surgical margins have been shown to predict risk of local recurrence. However, assays used for these analyses are time-consuming and therefore cannot be used in the intraoperative setting. Objective: To detect and quantify tumor-specific methylated promoter sequences in surgical margins in a time frame suitable for intraoperative use. Design: A novel quantitative methylation-specific polymerase chain reaction (QMSP) protocol. Methods: A total of 13 patients with head and neck squamous cell carcinoma (HNSCC) were initially characterized for molecular alterations in their tumor at the time of biopsy. Six primary tumors were found to harbor promoter hypermethylation for p16 and O 6-methylguanine-DNA-methyltransferase (MGMT) genes. Rapid QMSP was then used to identify promoter hypermethylation of these genes in the surgical margins. Results were compared with standard intraoperative histologic frozen section analysis and with conventional QMSP. Results: Using our rapid QMSP assay, we found that 3 patients had methylation-positive margins. Tumor margins from 2 patients were methylated for p16 alone, and margins from 1 patient were methylated for p16 and MGMT simultaneously. Molecular margin analysis was completed in less than 5 hours, a time frame appropriate for selected major HNSCC resections that require combined primary tumor resection, cervical lymphadenectomy, and complex reconstruction. This technique was comparable in sensitivity to conventional QMSP. Conclusion: Rapid molecular margin analysis using QMSP is feasible and may be performed intraoperatively in selected patients with HNSCC that requires extensive resection.

Immunohistochemical determination of the appropriate anti-hTERT antibodies for in situ detection of telomerase activity in frozen sections of head and neck squamous cell carcinomas and tumor margin tissues

“…An important cause of this is field cancerization (1,2) in the area around the tumor. In order to identify patients at risk, extensive studies have examined the specific biology of the invading tumor front and marginal tissue, and trials are in progress to identify the molecular or immunohistochemical markers best suited for characterizing tumor-free margin tissue (3)(4)(5)(6)(7)(8)(9).…”

Early Detection of Oral Squamous Cell Carcinoma ( O SCC ) – Role of Genetics: A Literature Review

“…This process has been detected in oral OSCC and it is a hallmark of many other cancers as well. In OSCC, hypermethylation of p16 occurs in 50-73% of the cases and that of p15 occurs in 60% of the cases [10][11][12][13]. Hypermethylations of p14ARK, p16 INK4a, P15, MGMT, DAPK, GSTP1 and RARB have been seen in dysplasias and in histologically normal appearing margins of OSCC resections.…”

Impact of methylation of the p16INK4agene on the prognosis ofhead and neck squamous cell carcinoma patients

“…If the role of gene methylation in carcinogenesis could be proven more clearly, it could be applied in various ways including chemotherapy using demethylating drugs 1 and frozen section biopsy of tissue adjacent to the tumor resected during surgery 27 .…”