Time-dependent effect of ribavirin on ESR1 mRNA expression in MDA-MB-231 cells as measured by real-time PCR. Cells were treated with 900 μM ribavirin for up to 120 h (n = 3). Every experiment has shown a time-dependent increase in expression of ESR1- however with a significant variation among the single experiments. The experiment with the maximum effect is shown. The experiment with the minimum response is shown in supplemental material 1.