HOXD13 and lung cancer: Moreover, the sPD-1 levels were significantly lower in stage II (128.9 ± 19.96, N = 13) and stage III (83.28 ± 11.13, N = 13) than in the control group (Figure 1B, *P < 0.05).We found a difference in age between the control group and the lung cancer patients; the age of the lung cancer group (57.40 ± 1.009, N = 108) was significantly higher than that of the control group (44.65 ± 1.574, N = 72) (Supplementary Figure S1C).