Gene expression profiles from DNA microarrays can provide molecular signatures that improve tumor classification, prognosis, and treatment options. While much of this work has focused on isolation of RNA from the resected tumor, fewer studies have utilized RNA from fine needle aspirates (FNA). In this pilot study we examined whether the gene signatures obtained from FNA samples would correlate with signatures taken from the resected tumor. Based on NSCLC gene expression profiles obtained from eleven sets of FNA and tumor samples we obtained a high concordance of FNA profiles matching their matched tumor sample. These results suggest that FNA samples may provide informative gene expression signatures regarding the potential aggressiveness of non-small-cell lung carcinomas