The percentage overlap between CD31 and pimonidazole signals was 97.8 ± 1.6%, suggesting that almost all detected blood vessels in tumor biopsies were located in hypoxic areas, whereas that overlapping of pimonidazole and CD31 was significantly lower (pimonidazole/CD31 = 23.6 ± 2.1%), indicating that large hypoxic tumor areas were not irrigated (Figure 1C). Here, PECAM1 is linked to neoplasm.