PGR and breast cancer: In this regard, it is important to underline that the expression levels of the selenoprotein GPX1 increased only in TNBC cells, whereas theyhad a decreased trend in other breast cancer subtypes and, in detail, a statistically significant decrease in ER/PR positive cells (Figure S2), in agreement with a recent paper that evidenced a crucial role of GPX1 in the metastatic process of TNBC cells through cell adhesion modulation [45].