Notably, using a high dose of 100 μM 5-FU to treat the CCA cells, the majority of the TYMS proteins were in the FdUMP-complexed inactive slower migrating (higher) forms following 5-FU treatment, and this lack of active unligated TYMS would lead to dNTP shortage and the cytotoxic DNA damage. This evidence concerns the gene TYMS and cholangiocarcinoma.