Figure 4A shows the detection of integrin subunits from five different GBM patients (left five lanes; the one lane on the right demonstrates CD31 and β‐actin). The group of GBMs demonstrate a heterogenous pattern of β3 chains, whereas the portions of αv light chains were strongly present in all samples. The expression in low‐grade astrocytomas was lower, especially the β3 chains, which were barely detectable. This evidence concerns the gene PECAM1 and astrocytoma (excluding glioblastoma).