CCL2 and glioblastoma: Considering that many cells produce CCL2 including tumor cells, non‐malignant astrocytes, endothelial cells, and macrophages and microglia in a brain tissue context 46, how much of the CCL2 in glioblastoma may be attributed to Δ133p53β, and whether this contribution is sufficient to affect tumor progression, remains to be determined.