Accordingly, the evaluation of GPX4 protein levels in two different PCa cell lines (PC3 and DU145) treated for 48 h with 20 mm lactic acid (i.e., a concentration of the nutrient that resembles the one found in in vivo tumor tissues and that takes into account the contribution of the heterogenous cell populations within the prostate TME [7, 17, 57, 58]) confirmed its overexpression upon lactic acid exposure (Fig. 1F,G and Fig. S1A,B), hence suggesting that microenvironmental lactic acid could mediate ferroptosis resistance in PCa. This evidence concerns the gene GPX4 and neoplasm.