NCOR1 and neoplasm: Indeed, in MCF7 xenograft mice, combined treatment with tamoxifen and TNFα or NCOR1 knockdown reduced tumor volume and weight compared to TNFα treatment or NCOR1 knockdown alone, suggesting that tamoxifen sensitivity is enhanced by TNFα and that NCOR1 is an important factor acting downstream of TNFα for overcoming tamoxifen resistance in vivo.