To explore whether ER gene targets could be permanently suppressed following long-term TAM exposure, the expression of the classically regulated genes, pS2 and progesterone receptor (PgR), was assessed by RT-qPCR and ICC in all cell-lines in the presence and absence of E2 (Fig. 3a and 3c). Here, ESR1 is linked to intrahepatic cholangiocarcinoma.