The tumor vessel densities positive for CD31 in SW620 tumors treated with vehicle, irinotecan, mABL001, and combination were 0.71 ± 0.05%, 0.48 ± 0.03%, 0.36 ± 0.03%, and 0.18 ± 0.01%, respectively (Figure 3B). Here, PECAM1 is linked to neoplasm.