Tel is an antiviral agent that inhibits hepatitis C virus (HCV) NS3/4A serine protease [18] and, to date, no data regarding Tel effect on BC exist but we recently demonstrated that Tel reduces ERα levels by affecting receptor expression at transcriptional levels, perturbs E2:ERα signaling by inhibiting receptor transcriptional activity, and prevents basal and E2‐dependent cell proliferation in different BC cell lines [19]. This evidence concerns the gene ESR1 and breast cancer.