[18F]RCCB6 and 18F-FDG PET/CT imaging in patient with advanced NPC. (A) [18F]RCCB6 immuno-PET/CT images showing primary NPC (red arrowhead) and multiple systemic metastases, including cervical lymph nodes (yellow arrowheads), bone (green arrowhead), lung (orange arrowhead), liver (blue arrowhead), and Omental bursa lymph nodes (pink arrowhead) in patient 20. (B) 18F-FDG PET/CT images of same patient, demonstrating corresponding lesions. Credit: B. Shi and W. Wei et al. Renji Hospital, School of Medicine, Shanghai Jiao Tong University.

A novel immuno-PET/CT imaging technique has identified and validated a potent biomarker for nasopharyngeal cancer (NPC). The biomarker, CD70, is highly and constantly expressed in NPCs, and CD70-targeted immuno-PET/CT has proven effective in accurately detecting primary and metastatic NPC lesions.

This research, published in The Journal of Nuclear Medicine, has the potential to enhance diagnosis and guide personalized therapies for NPC patients.

NPC is a type of head and neck cancer that is found in the upper part of the throat, behind the nose and by the base of the skull. While NPC is rare, it is more common in certain parts of South Asia, the Middle East, and North Africa. NPC is associated with the Epstein-Barr virus (EBV)—a common herpesvirus that causes mononucleosis—and much research focuses on this relationship.

"We know that the biomarker CD70 is crucial in the immune response to EBV infection, " noted Weijun Wei, MD, Ph.D., associate research professor in the Department of Nuclear Medicine at Renji Hospital School of Medicine, Shanghai Jiao Tong University, in Shanghai, China.

"Since many NPC cases are associated with EBV infection, we sought to further investigate the role and diagnostic potential of this biomarker."

In the study, CD70 expression was analyzed in 80 archived NPC specimens and correlated with clinical and pathologic features. Using 18F-RCCB6, a single-domain antibody–derived tracer specific for human CD70, the diagnostic efficacy of 18F-RCCB6 immuno-PET/CT was assessed in 25 patients with NPC and compared with that of 18F-FDG PET/CT.

CD70 was positively expressed in 90% of NPC specimens, with expression levels strongly correlated with EBV. In patients, 18F-RCCB6 uptake correlated well with CD70 expression. 18F-RCCB6 immuno-PET/CT achieved a 100% detection rate of the primary tumor and a 93% detection rate of local lymph node metastasis in patients with early-stage disease.

Compared to 18F-FDG, 18F-RCCB6 demonstrated higher sensitivity in detecting lymph node metastasis and equivalent detection abilities for primary lesions and most distant metastases.

Notably, 18F-RCCB6 immuno-PET/CT demonstrated better evaluation of skull-base invasion with a clear border and bone metastases.

"These findings are critical for improving NPC management, " noted Wei.

"18F-RCCB6 immuno-PET/CT offers precise detection of primary tumors, metastases, and recurrent lesions, reducing false positives from inflammatory uptake seen with 18F-FDG.

"This accuracy can enhance radiotherapy planning and guide personalized therapies, such as CD70-targeted immunotherapies. For patients, this translates to earlier detection, reduced overtreatment, and better prognostication."

More information: Binyu Shi et al, CD70-Targeted [18F]RCCB6 Immuno-PET/CT Imaging in Patients with Nasopharyngeal Carcinoma: A Proof-of-Concept Study, Journal of Nuclear Medicine (2025). DOI: 10.2967/jnumed.125.269585  Journal information: Journal of Nuclear Medicine