Novel Radiotracer Identifies Critical Cancer Biomarker

A new molecular imaging agent can accurately identify a crucial biomarker found among many different types of cancer. Precise visualization of the trophoblast cell surface antigen 2 (Trop2) biomarker can provide physicians with valuable insights for diagnosis, development of a personalized treatment plan, and response assessment. The research was published in The Journal of Nuclear Medicine.

Trop2 has garnered interest among cancer researchers recently due to the significant role it plays in cell self-renewal, proliferation, transformation, and organ development. It is commonly found in triple-negative breast cancer, colorectal cancer, gastric carcinoma, pancreatic cancer, and non–small cell lung cancer, among other solid tumors.

“Trop2 is an emerging biomarker for developing next-generation diagnostic and therapeutic agents for solid tumors and has the potential to be a game-changer for cancer treatment,” said Weijun Wei, MD, PhD, associate research professor in the Department of Nuclear Medicine at Renji Hospital School of Medicine at Shanghai Jiao Tong University in China.

“However, efficiently visualizing Trop2 expression and selecting patients who might benefit from Trop2-targeted therapies is a clinical challenge.”

To further the research on Trop2, Wei and colleagues developed two novel Trop2-targeted radiotracers:¹⁸F-AlF-RESCA-T4 and¹⁸F-AlF-RESCA-RT4. Preclinical imaging and blocking studies were performed on tumor-bearing mice to determine safety and efficacy. A pilot clinical trial including three patients with suspected lung cancer was also conducted. This trial included a head-to-head comparison of PET/CT imaging with¹⁸F-AlF-RESCA-T4,¹⁸F-AlF-RESCA-RT4, and a previously developed radiotracer,⁶⁸Ga-NOTA-T4.

Prominent tumor uptake was observed with both¹⁸F-AlF-RESCA-T4 and¹⁸F-AlF-RESCA-RT4, however the latter showed substantially reduced kidney accumulation. In the clinical trial’s head-to-head comparison,¹⁸F-AlF-RESCA-T4 performed best. Initial¹⁸F-AlF-RESCA-T4 immuno-PET/CT imaging demonstrated the ability to visualize Trop2 expression in suspected lung cancer patients; it was also able to differentiate lung inflammation, such as tuberculosis, from cancer.

“PET imaging with¹⁸F-AlF-RESCA-T4 will allow physicians to identify patients with Trop2-positive tumors so they can receive Trop2-targeted treatments,” noted Wei. “This is the cornerstone of precision medicine: selecting the right treatment for the right patient.”