Molecular Determination of Primary Versus Metastatic Squamous Cell Carcinoma (SCC) of the Lung in the Context of SCC of the Head and Neck (H/N) — Comparison of Methodologies
JR Pettus, JL Brown, X Yang, WB Coleman, GJ Tsongalis. Dartmouth-Hitchcock Medical Center, Lebanon, NH; University of North Carolina - Chapel Hill, Chapel Hill, NC
Background: Considering similar risk factors, patients with SCC H/N are at a high risk of developing SCC within the lung. These lesions are often characterized as metastatic SCC, even though they often present as solitary masses. Given similar histologies, the distinction between metastatic and primary SCC is often difficult. Thus, molecular methods may be clinically useful in the evaluation of tumor relatedness. It has previously been shown that assessment of allelic variation at the level of microsatellite sequences can be utilized to discriminate multiple primary versus metastatic SCC of H/N and lung via a rapid, sensitive, method independent of the presence of normal tissue. The method is amenable to the analysis of DNA from paraffin-embedded specimens. The goal of this study was to refine this methodology via implementation of fluorescent-labeled primers and/or multiplexed reactions with automated detection.
Design: Genomic DNA was extracted from paraffin-embedded tumor samples from nine patients who had undergone resection of SCC of both the H/N and lung. PCR was performed to determine allelic variation, and the cases were scored for mutually exclusive allelic losses. Comparison was made between microsatellite PCR with PAGE analysis versus fluorescent product detection. The same samples were analyzed with the Ampfister Identifiler multiplex (Applied Biosystems).
Results: All three methods yielded interpretable results. Samples consistent with metastatic lung lesions were characterized by either identical allelic losses or additional allelic losses as compared to SCC H/N, while lesions consistent with metachronous primary SCC of the lung were characterized by retention of alleles that were lost in the SCC H/N.
Conclusions: The use of fluorescent-labeled primers improves throughput by streamlining the analysis of PCR products. Likewise, analysis of patient samples using multiplex PCR can yield sufficient information to determine relatedness of neoplasms in a single PCR reaction. The results of this study confirm that molecular methods can distinguish primary vs. metastatic SCC of the lung in the context of SCC H/N and that practical clinical laboratory assessment of these neoplasms is feasible. Accurate characterization of these lesions may significantly impact clinical management strategies for these patients.
Category: Head & Neck
Tuesday, March 23, 2010 1:00 PM
Poster Session IV # 151, Tuesday Afternoon