The percentages of mouse CD31, CD90, CD49b, CD14 and CD11c positive cells in the subpopulation of the cancer cells were almost below the detection level (0.9%: CD31; 0.4%: CD90; 1.6%: CD49b; 1.7%: CD14 and 0.4%: CD11c (Figure 3B). Here, PECAM1 is linked to cancer.