Abstract: The present invention relates to the prediction of the survival time of a patient suffering from a cancer. The inventors identified in blood from healthy donors a subpopulation of WIT cells that expresses CD73 and displays immunosuppressive phenotype and functions (i.e., production of immunosuppressive molecules and inhibition of ?ßT cell proliferation). Furthermore, they detected the presence of CD73+ ?? T cells in immune infiltrates of freshly resected breast cancer specimens. Altogether, these data suggest that part of ?? T cells infiltrated in the breast cancer microenvironment presents a regulatory phenotype characterized by CD73 expression, and are likely to display pro-tumor functions through the mechanisms they described in vitro.