Our data showed a significant decrease of Mfsd2a protein expression in vascular endothelial cells (Fig. 2E) within brain metastases originating from primary breast cancer (Fig. 2A,B), lung cancer (Fig. 2C), and NEPC (Fig. 2D) patient samples, as revealed by double immunofluorescence labeling with anti-Mfsd2a and anti-CD34 antibodies. Here, CD34 is linked to lung cancer.