Fig 1: S100A8 and S100A9 staining of paraffin embedded clinical HNSCC samples by immunohistochemistry.(A) *Hematoxylin-eosin staining of an example 4 mm tissue section. Note that this image is identical to (G). (B) Anti-S100A8 staining of the corresponding section. (C) Enlarged stained regions of the (t) tumor (tumor and tumor stroma) and (h) healthy (healthy epithelium and stroma) tissue areas. (D–F) Histopathological scoring of S100A8 staining in selected regions. Scored expression levels are displayed in (D) tumor vs. healthy stroma (E) tumor vs. tumor stroma and (F) tumor vs. healthy epithelium. (G) *Hematoxylin-eosin staining of an example 4 mm tissue section. Note that this image is identical to Figure 3A, and shown for easier view only. (H) Anti-S100A9 staining of the corresponding section. (I) Enlarged stained regions of the (t) tumor (tumor and tumor stroma) and (h) healthy (healthy epithelium and stroma) tissue areas. (J–L) Histopathological scoring of S100A9 staining in selected regions. Scored expression levels are displayed in (J) tumor vs. healthy stroma (K) tumor vs. tumor stroma and (L) tumor vs. healthy epithelium.