Intraoperative molecular margin analysis in head and neck cancer.
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.


METHODS
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 O6-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.


CONCLUSIONS
Rapid molecular margin analysis using QMSP is feasible and may be performed intraoperatively in selected patients with HNSCC that requires extensive resection.
Goldenberg
David
D
Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Md, USA.
Harden
Susan
S
Masayesva
Brett G
BG
Ha
Patrick
P
Benoit
Nicole
N
Westra
William H
WH
Koch
Wayne M
WM
Sidransky
David
D
Califano
Joseph A
JA
D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000601:surgery*; D019175:DNA Methylation; D004273:DNA, Neoplasm; D019942:Genes, p16; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000601:surgery*; D006801:Humans; D007432:Intraoperative Period; D016133:Polymerase Chain Reaction / Q000379:methods*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012680:Sensitivity and Specificity
D004273:DNA, Neoplasm