MKI67 and neoplasm: New studies investigating additional determinants of ctDNA% should utilize next-generation targeted imaging (e.g., [68Ga]PSMA-PET/CT in prostate cancer) for more precise quantification of disease burden and location40—as well as investigate the potential relevance of tumor cell proliferation indicators (e.g., Ki-67-positive tumor nuclei or total lesion glycolysis) and microenvironmental factors (e.g., tumor vascularization, macrophage infiltration) on ctDNA%.