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.