Notably, the decreased content in CD45-positive cells and reduced vessel density of B16F1 tumors, as compared to mammary AT-3 tumors, was maintained when B16F1 tumors were grown for 21 days in mammary fat pads of female mice, thus indicating that the main distinguishable features between these tumor types were irrespective of female sex, the implantation site, or length of experiment (Supplementary Fig. 4). This evidence concerns the gene PTPRC and neoplasm.