ENTPD1 and breast cancer: Nevertheless, the association of CD127− CD39hi, but not of CD127+ CD39lo Trm cells with improved OS and BC-specific survival in the METABRIC cohort, their increase presence at the tumor site compared to adjacent tissue and the peripheral blood, and in metastatic vs. nonmetastatic lymph nodes suggests that CD39 is a marker of bona fide tumor-reactive T cells also in BC.