PET imaging and biodistribution studies in NSG mice bearing high PD-L1-expressing triple-negative breast cancer human xenografts using Al[18F]F-NODA-DK222 resulted in high contrast images with good tumor uptake (13.4 ± 0.1 %ID/g 60 min p.i.), high accumulation in the kidneys (57.7 ± 0.5 %ID/g 60 min p.i.)and low accumulation in the liver (198). Here, CD274 is linked to triple-negative breast carcinoma.