IRS1 and cholangiocarcinoma: This observation was also confirmed in vitro by the same authors, who compared immortalized cholangiocytes (MMNK1), immortalized cholangiocytes subjected to long-term oxidative stress (ox MMNK1 L) to induce oxidative stress resistance, and different CCA cell lines, detecting an increased expression of IRS1 in oxidative stress resistant ox MMNK1 L and CCA cells respective to immortalized cholangiocytes.