Figure 1.

Elevated EP4 receptor expression in human colon cancer specimens. Immunohistochemistry (IHC) staining of EP4 receptor protein was performed in human colon tissue specimens. (A) The staining of normal colonic mucosa shows low EP4 receptor protein expression on the apical membrane. (B) Elevated EP4 staining was observed in adenocarcinomas lesions. (C) Differences between IHC scores for normal, adenomatous, and cancerous lesions are shown as a box and whisker plot. The distribution of pair-wise comparisons of differences in EP4 staining scores shows a significant difference in EP4 receptor staining in malignant colonic lesions compared with normal and adenoma lesions (*p < 0.0001). Each dot represents IHC score (intensity of stain X percentage of cells stained) generated after staining formalin-fixed paraffin embedded tissues for EP4 antibody by IHC.