VCAM1 and melanoma: In the clinic, patients with BM are treated mainly with radiotherapy, and a number of preclinical studies have highlighted the impact of external radiotherapy on the tumor microenvironment and inflammatory processes in particular.26 Lugade and colleagues showed an increase in VCAM-1 on B16 melanoma tumor vessels in vivo following external radiotherapy.27 Similarly, in the present study we found an increase in vascular VCAM-1 expression 24 h and 72 h following WBRT in tumor vessels, but not in healthy brain vessels (Supplementary Fig. 5).