The use of macromolecular agents based on dendrigraft poly-L-lysines (DGLs), using chlorotoxin (CTx) as a tumor-specific ligand, has been explored with promising results in the field of clinical diagnosis of brain tumors using MRI studies, where it has been showed that the signal enhancement of mice treated with CTx-modified contrast reached peak level at 5 min for both glioma and liver tumor, significantly higher than unmodified counterpart. The gene discussed is CYP27A1; the disease is glioma.