Results (Figure 4a) revealed that the GCC2 protein concentrations were significantly higher (normal 9.07 pg/mL vs. patients’ 26.28 pg/mL, p < 0.001) in early-stage lung cancer patients (T1aN0-T1bN0; n = 30) than in the normal controls (n = 16). This evidence concerns the gene GCC2 and lung cancer.