CXCR4 and neoplasm: Two reasons for this result are apparent: (i) the radioligand (76Br-HZ270-1) was actually hydrophilic (LogD = − 0.72), not lipophilic as estimated from a structure-based calculation (ChemDraw/Chem3D/ChemFinder Software, PerkinElmer Informatics) (estimated LogP = 2.17); (ii) both the intracranial U87-CXCR4 and PCNSL-15 animal tumor models had comparatively intact BBB and BTB, as seen on contrast MRI.