CD68 protein expression levels in lung tumor tissue, adjacent tumor tissue and surrounding non-tumorous lung tissue from lung cancer patients.

Scale bar = 20 µm. (A) Adenocarcinoma; (B) Squamous cell carcinoma; (C) adjacent adenocarcinoma tissue; (D) adjacent squamous cell carcinoma tissue; (E) non-tumor. CD68 were mainly detected in cytoplasm of macrophages with brown staining. Positive cell number of CD68 in adjacent lung cancer tissue (C–D) was more than that in lung cancer tissues (A–B) and non-tumorous lung tissues (E) (n = 67, P<0.05).