CD8A and metastatic malignant neoplasm in the lymph nodes: Interestingly, follow-up [18F]FDG PET/CT 8 weeks after [89Zr]Zr-Df-IAB22M2C PET/MRI revealed regression of the CD8 PET/MRI-positive axillary lymph node metastasis, while the CD8 PET/MRI-negative hilar lymph node metastasis increased in volume and [18F]FDG uptake (Figure 2E-F).