In vivo PET imaging analysis in high levels of uPAR expressing U87MG glioma cells and uPAR-negative MDA-MB-435 breast cancer cells revealed gradual increase of 64Cu-DOTA-AE105 uptake in U87MG tumors with time and uptake that remained close to background in the case of MDA-MB-435 tumors. This evidence concerns the gene PLAUR and breast cancer.