Prostaglandin E2 levels and lymphocyte subsets in portal venous drainage of colorectal cancers.

Local immunosurveillance may play an important role in the growth and spread of tumors. To investigate the local immune response, we determined prostaglandin E2 (PGE2) levels (n = 23) and lymphocyte subsets (n = 10) in the portal vein draining the tumors of patients with colorectal cancer. PGE2 levels in the portal vein were significantly higher than those in the radial artery. Portal PGE2 levels in patients with advanced stage tumors (Duke's C and D) and lymph node metastases were significantly higher than those of patients with Duke's A and B tumors without lymph node metastases. Moreover, four of the nine patients with portal PGE2 levels greater than 100 pg/mL had liver metastases within 2 years of surgery. There were no differences in lymphocyte subsets between the portal vein and the radial artery. PGE2 levels in the portal vein draining colorectal tumor may thus be closely related to tumor progression and recurrence and may serve as a predictor of tumor recurrence in patients with colorectal cancer.