Regional differences in PGE
levels and 15-PGDH immunoreactivity in human CRCLM. A) Box and whisker plot of the median, inter-quartile range and range of the PGE2 level in peripheral and central areas of CRCLM. Immunohistochemistry for COX-2 (B) and 15-PGDH (C) in human CRCLM. In each case, a low-power view of the whole section covering the radius of a CRCLM is shown (bar = 1 mm). Areas in the centre (C) and periphery (P) of the tumour are marked with a green square and are shown as the corresponding high power view, as well as a negative control section, for which the primary antibody was omitted (bar = 100 μm). D)-E) Box and whisker plots of the median, inter-quartile range and range of COX-2 immunoreactivity (D) and 15-PGDH immunoreactivity (E) in the peripheral and central area from 20 human CRCLM. Immunohistochemical staining in D) and E) is measured in arbitrary units on a scale of 0–220 derived from the Aperio Imagescope software.