Researchers at The Wistar Institute and the University of Pennsylvania have developed a panel of ten genes that is a highly-accurate tool for distinguishing between primary lung cancer and metastatic squamous cell carcinoma of the lung in patients with previous head and neck malignancies. Wistar and Penn researchers developed the 10-gene classifier panel from among 100 high-potential candidate genes identified using more than 9,000 probes. This integrative biomarker tool has been validated on data from four independent laboratories on more than 120 samples of primary lung squamous cell carcinoma (LSCC) and head and neck squamous cell carcinoma (HNSCC) and by quantitative RealTime PCR. The panel has been shown to differentiate the two tumor types with an average accuracy of 96%.