Effect of gene polymorphism of COMT and OPRM1 on the preoperative pain sensitivity in patients with cancer.

OBJECTIVES To evaluate the effect of COMT and OPRM1 gene polymorphisms on the preoperative pain sensitivity in tumor patients. METHODS 300 cases of cancer patients undergoing elective surgery were included, and the Val158 Met loci of COMT gene and OPRM1 loci of A118 G gene were genotyped by PCR-RFLP. Pain threshold and pain tolerance threshold were measured using electrical stimulation to investigate the preoperative pain sensitivity in patients with different genotypes. RESULTS For the COMT gene, the pain threshold and pain tolerance threshold of patients with M allele both decreased (both P < 0.001); for PPRM1 gene, pain threshold and pain tolerance threshold of patients with G allele decreased (both P < 0.001). We also found that there was an interaction between the two genes. CONCLUSION Gene polymorphisms of COMT and OPRM1 were correlated with the preoperative pain sensitivity of cancer patients. The patients with M allele of COMT and G allele of OPRM1 had higher preoperative pain sensitivity.