S100A9 and neoplasm: We found that neutrophils predominantly infiltrated the nontumoral area rather than the tumoral area, and CD15+ cells were the main cell population that expressed S100A9 protein (58.19 ± 20.80%) in nontumor areas, but this proportion was significantly reduced in tumor areas (29.01 ± 24.20%) (Figure 6A–6C).