Figure 2.

Immunohistochemistry (IHC) staining of aquaporin 4 (AQP4) in paraffin-embedded sections of the lung adenocarcinoma (ADC) from humans. Anti-AQP4 antibody labels in non-neoplastic lung tissues. Arrows indicate the localization of the type I pneumocytes and macrophages (A). Anti-AQP4 antibody labels in the cancer lung tissues. Arrows indicate the localization of AQP4 in the cytoplasmic membrane in the cancer cells (B) and aberrant nuclear reaction in cancer cells (C). No staining was observed when isotype-specific immunoglobulins from non-immunized rabbits were used instead of the primary antibody (negative control) (D). Immunoperoxidase labeling of AQP4 from the human stomach (positive control) (E). The labeling is seen in the basolateral plasma membrane of the surface epithelial cells and parietal cells of gastric gland cells. The blue color represents a positive staining for the hematoxylin counterstain, and the brown color represents positive AQP4 stain.