Following this application, Wasenang et al. [25] developed a different approach to discriminate between CCA and non-tumoral biliary disease (i.e. chronic cholecystitis, cholangitis, cholelithiasis) relying on the methylation level of opioid binding protein cell adhesion molecule-like (OPCML) and 5’-Hoxd genes (HOXD9) as determined in cfDNA; the combined assessment showed high specificity and positive predictive value, suggesting that it could prevent misdiagnosis of CCA, thus potentially sparing unnecessary surgical procedures. This evidence concerns the gene OPCML and cholelithiasis.