PGR and neoplasm: Furthermore, the study explores the inhibitory effect of estrogen on the growth of MC38 tumors, elucidating its mechanism of action through the downregulation of PD-L1 expression and modulation of tumor-associated cell populations; The efficacy of mifepristone, a progesterone receptor antagonist, has been demonstrated in enhancing lifespan and enhancing overall well-being in different spontaneous murine cancer models.