TET1 and cholangiocarcinoma: These co‐substrates of the TET1 dioxygenase were found to promote the formation of 5hmC and malignant tumorigenesis in CCA cells.[37b] While numerous studies have examined the function of TET1 in CCA, the potential of leveraging TET1's epigenetic capabilities to impede cholangiocarcinoma progression remains uncharted territory.