Chaiteerakij et al. investigated 18 functional SNPs in nine genes associated with CCA risk and survival and showed that the rs2143417 allele T (Odds Ratio (OR) = 1.52, 95%-Confidence interval (95% CI) = 1.21–3.91, p = 0.0003) and rs689466 allele T (OR = 1.36, 95% CI = 1.10–3.69, p = 0.005) of PTGS2 is significantly associated with the risk of CCA [26]. This evidence concerns the gene PTGS2 and cholangiocarcinoma.