PTPRC and neoplasm: Of note, we failed to detect ZEB1 protein in CD45-positive leucocytes (including macrophages) in either PyMT-Fib-cKO or PyMT-Fib-WT tumours (Supplementary Fig. 2i; right panels), suggesting that ZEB1 is essentially absent in leucocytes in the MMTV-PyMT model.