Progesterone Receptor-Dependent Downregulation of MHC Class I Promotes Tumor Immune Evasion and Growth in Breast Cancer

To determine the effect of progesterone receptor/progesterone on MHC class I expression, scientists treated human and mouse mammary tumor cell lines with progesterone and/or interferon and measured expression of genes involved in antigen processing and presentation, as well as surface MHC class I expression.