Chidambaran V, et al. – The researchers evaluated deoxyribonucleic acid methylation at the mu-1 opioid receptor gene (OPRM1) promoter, as a predictor of preoperative, acute, and chronic postsurgical pain (CPSP) as DNA methylation was a potent repressor of gene expression. They identified novel CPSP biomarkers in an active regulatory region of the OPRM1 gene that binds multiple transcription factors. As per the outcomes, inhibition of binding by DNA methylation potentially decreased the OPRM1 gene expression, leading to a decreased response to endogenous and exogenous opioids, and an increased pain experience.