Allele A of tumor necrosis factor (TNF, encoding TNF-α) rs1800629 was similarly associated with the risk of CCA and IL6 rs1800795 allele C homozygous is associated with reduced IL-6 production, while the allele G homozygous is associated with increased IL-6 production (Figure S1) [53]. This evidence concerns the gene IL6 and cholangiocarcinoma.