Clinical significance of peripheral blood and tumor tissue PGE2 levels in patients with colorectal carcinoma

AIM: To determine the dynamic changes in the levels of peripheral blood and tumor tissue prostaglandin E₂ (PGE₂) in patients with colorectal carcinoma and to analyze their clinical significance.

METHODS: Sixty-one patients with colorectal carcinoma were included in the study. Of these patients, 15 had distant metastasis and 46 did not show any obvious distant metastasis; 11 underwent palliative resection, 9 underwent laparotomy, and 41 received radical resection; 20 had stage A-B disease, 26 had stage C disease, and 15 had stage D disease. Thirty healthy people were used as controls. The levels of peripheral blood and tumor PGE₂ were assayed before and after operation.

RESULTS: Patients with colorectal cancer had high concentrations of peripheral blood PGE₂ before operation. However, peripheral blood IL-2 level and CD4⁺/CD8⁺ ratio were lower in patients with colorectal cancer than in controls before operation. Peripheral blood PGE₂ levels had a negative correlation with IL-2 level and CD4⁺/CD8⁺ ratio. Peripheral blood PGE₂ levels were higher in patients with stage D disease than in those with stage A-C disease. Peripheral blood PGE₂ levels had a positive correlation with tumor size. The level of PGE₂ in tumor tissue was 3.7-fold as high as that in normal bowel mucosa [134.43 ng/(g•mL) ± 119.50 ng/(g•mL) vs 61.01 ng/(g•mL) ± 30.98 ng/(g•mL), 35.80 ng/(g•mL) ± 10.99 ng/(g•mL), P < 0.05, 0.01]. After operation, peripheral blood PGE₂ levels decreased and IL-2 level and CD4⁺/CD8⁺ ratio increased. Peripheral blood levels of PGE₂ decreased almost to normal in patients after radical resection, but were still higher in those after palliative resection.

CONCLUSION: Peripheral blood PGE₂ in patients with colorectal carcinoma originates from the tumor. PGE₂ is involved in the immunologic hypofunction in patients with colorectal carcinoma before operation. Removal of tumor may improve the state of systemic cellular immunity in patients with colorectal carcinoma.