68Ga-MY6349 PET/CT imaging to assess Trop2 expression in multiple types of cancer.

Background Considering trophoblast cell surface antigen 2 (Trop2) is overexpressed in a wide range of human epithelial cancers, it presents an attractive target for the diagnosis and treatment of multiple types of cancer. Herein, we have developed a Trop2-specific radiotracer, 68Ga-MY6349, and present a prospective, investigator-initiated trial to explore the clinical values of 68Ga-MY6349 PET/CT. Methods In this translational study, 90 patients with 15 types of cancer, who underwent 68Ga-MY6349 PET/CT, were enrolled prospectively. Among them, 78 patients underwent paired 68Ga-MY6349 and 18F-FDG PET/CT, and 12 patients with prostate cancer underwent paired 68Ga-MY6349 and 68Ga-PSMA-11 PET/CT. Results Among the 90 patients across 15 types of cancer, 68Ga-MY6349 uptake in tumors was generally high but heterogeneous, varying among lesions, patients, and cancer types. Trop2 expression level determined by immunohistochemistry was highly correlated with 68Ga-MY6349 uptake at primary and metastatic tumor sites. 68Ga-MY6349 PET/CT showed higher tumor uptake (quantified by SUVmax) than 18F-FDG PET/CT in certain types of cancer, including breast (7.2 vs. 5.4, P < 0.001), prostate (9.2 vs. 3.0, P < 0.001), and thyroid cancers (8.5 vs. 3.7, P < 0.001). When compared with 68Ga-PSMA-11, 68Ga-MY6349 PET/CT exhibited comparable lesion uptake (12.2 vs. 12.5, P = 0.223) but a better tumor-to-background contrast (15.8 vs. 12.2, P < 0.001) for primary and metastatic prostate cancer, allowing visualization of more metastatic lesions. Conclusion 68Ga-MY6349 PET/CT is a non-invasive method for comprehensively assessing Trop2 expression in tumors, which can improve the diagnosis and staging for cancer patients, and aid in the decision-making for Trop2-targeted therapies and advancing personalized treatment.