Low expression of CysLT1R and high expression of CysLT2R mediate good prognosis in colorectal cancer

Colorectal cancer is the third most common cancer type in the Western world. In search of new treatment possibilities, the inflammation mediators, know as cysteinyl leukotrienes (CysLTs), have been shown to regulate intestinal epithelial cell survival and proliferation via the CysLT1R, and cell differentiation via the CysLT2R. These results prompted us to investigate the significance of CysLT1R and CysLT2R expression in colorectal cancer tissue for patient survival. The CysLT1R, CysLT2R, β-catenin and Bcl-xL protein expression levels were evaluated by immunohistochemistry in a tissue microarray of 329 colorectal patients. We found that high nuclear expression of CysLT1R is associated with a poor prognosis, whereas high nuclear expression of CysLT2R is associated with a good prognosis. We also observed that patients with colorectal tumours characterised by high CysLT1R but low CysLT2R nuclear expression had the lowest survival expectancy, whereas patients with colorectal tumours characterised by low CysLT1R but high CysLT2R nuclear expression had the best survival expectancy. Interestingly, β-catenin as a single prognostic marker did not exhibit any prognostic value. However, in patients with tumours characterised by a high CysLT1R nuclear expression, an elevated β-catenin nuclear expression had a significantly prognostic value.In conclusion these data indicate that nuclear expressions of CysLTRs are potential prognostic indicators of colorectal cancer.