PTPRC and breast cancer: Enrichment of CD45, T cell markers, and the natural killer cell marker CD56 in BC-associated TDLUs relative to BCs or preceding BBD-TDLUs is of interest and merits further study [62,63]; related observation include reduced CD56-positive cells and decreased expression of its activating ligand MICA in BBD versus normal lobules [64], and associations between mutational burden and CD45+ cells in benign tissue [14].