Figure 2

LunX mRNA is the most specific gene marker for lung cancer cells in peripheral blood. LunX, CK19, CEA, VEGF-C, hnRNP A2/B1 and β-actin mRNA from each peripheral blood sample were detected by real-time RT-PCR, and mRNA copy number was determined by reference to the standard curve, as described in methods. The copy number of each mRNA was further normalized as the ratio to the copy number of β-actin in all samples. For each gene marker, when the copy number was less than 100, it could not be detectable as a negative case. All the negative results of each indicated gene were shown as number undetected. The median is marked as "---" in each group. Where the frequency of negative cases is > 50%, the median cannot be shown.