Next, we defined a classification tree based on a sub-panel of six markers (consisting of TNF-α, CYFRA 21.1, IL-1ra, MMP-2, MCP-1, sE-selectin) selected from the Random Forest algorithm within the RPART software package to provide a convenient and useful algorithm for distinguishing NSCLC from benign controls. This evidence concerns the gene MMP2 and non-small cell lung carcinoma.