Fig 1: Immunohistochemical localization of LTB4R/LTB4R2 and CYSLTR1/2. Leukotriene receptors are horizontally displayed from the top to the bottom. Vertical sections represent the distinct histological tissues examined. Images show sections with low (large picture) and higher (right lower corner) magnification example. In non-transformed mucosa of cancer patients and control mucosa, details display a representative section from basal stratum with adjacent submucosal tissue. Furthermore, control panels show a mucosal papilla with circularly oriented basal membrane. Positive receptor detection appears as brown staining (microscope: Nikon F200 camera 990). For LTB4R (a-c), the receptor is predominately located within the cytosol of cancer cells and normal esophageal epithelium. Within the non-transformed epithelia LTB4R reaches medium (b) to low (c) staining intensity in basal cells and a further reduction in luminal areas. The reactions for LTB4R2 also show a cytosolic receptor pattern (d-f). Non-cancerous tissues (E and F) present low LTB4R2 expression in basal strata. An up-regulation of LTB4R2 can be seen in superficial epithelial layers instead. CYSLTR1 results are demonstrated in the pictures below (g-i). Cancerous and non-cancerous epithelial esophageal cells present a cytosolic staining. As depicted, CYSLTR1 is also located within the nuclei of cancer cells and non-transformed mucosa of patients with cancer (g and h). A weak CYSLTR1 expression is present in basal stratum of the normal esophageal epithelium of cancer patients with up-regulation in superficial layers. CYSLTR1 staining remains low across all cellular layers of dyspeptic control. CYSLTR2 is also localized within the cytoplasm (j-l). Both groups with normal esophageal epithelium display a weak CYSLTR2 reactivity in basal compartments, whereas CYSLTR2 is up-regulated in luminal areas (i and l). ESCC = esophageal squamous cell cancer; NTSE = non-transformed squamous epithelium of cancer patients; CSE = control squamous epithelium