Neuroendocrine prostate cancer (NEPC) represents one of the most formidable challenges in oncology today, owing to its aggressive behavior, resistance to conventional therapies, and notorious difficulty in detection. Unlike more common prostate cancer subtypes, NEPC frequently evades traditional prostate-specific membrane antigen (PSMA)-based imaging methods, which undermines accurate staging and optimal treatment planning. A groundbreaking study unveiled at the Society of Nuclear Medicine and Molecular Imaging (SNMMI) 2026 Annual Meeting introduces a pioneering theranostic approach targeting RET, a novel biomarker selectively expressed on neuroendocrine prostate cancer cells. This innovative strategy promises to revolutionize the diagnostic and therapeutic landscape for patients battling this lethal malignancy.
RET, or rearranged during transfection, is a receptor tyrosine kinase implicated in multiple oncogenic processes. Historically studied in thyroid and lung cancers, RET’s relevance to neuroendocrine prostate cancer had remained unexplored until recent investigations identified its overexpression in NEPC tumors. This discovery opened new avenues for the development of targeted molecular tools capable of binding RET with high specificity and affinity. Researchers built upon this foundation by engineering RET-binding peptides designed to serve dual functions: enabling high-contrast positron emission tomography (PET) imaging and delivering therapeutic payloads in the form of radioligand therapy.
The research team, led by Dr. Yongxiang Tang from Xiangya Hospital, Central South University in China, meticulously validated RET as a robust biomarker for NEPC through immunohistochemical analysis of 134 human prostate tissue samples. Their findings confirmed a stark contrast in RET expression between neuroendocrine and non-neuroendocrine prostate cancer specimens, underscoring RET’s potential as a differentiating molecular target. This facilitated the selection of RET-L7, a peptide exhibiting strong and selective binding to the RET receptor, forming the foundation for the theranostic agents developed.
For imaging applications, the peptide RET-L7 was conjugated with the chelator DOTA and radiolabeled with Gallium-68 (^68Ga), creating [^68Ga]Ga-DOTA-RET-L7. This radiotracer demonstrated exceptional capability in targeting RET-positive tumors in preclinical xenograft models, enabling high-contrast PET imaging. The specificity of tumor uptake was verified through blocking studies, indicating minimal off-target accumulation and rapid systemic clearance, properties crucial for optimizing image resolution and patient safety. This represents a transformative advance over PSMA-based imaging, which often fails to detect NEPC lesions due to low or absent PSMA expression.
Complementary to diagnostic imaging, the therapeutic counterpart was developed by labeling DOTA-RET-L7 with Lutetium-177 (^177Lu), a beta-emitting radionuclide that delivers cytotoxic radiation to tumor cells upon receptor-mediated internalization. In preclinical experiments, a single dose of [^177Lu]Lu-DOTA-RET-L7 demonstrated a clear, dose-dependent prolongation of survival in mice bearing RET-positive tumors. Importantly, comprehensive toxicity assessments revealed no significant hematologic or organ-related side effects, highlighting the safety profile of this targeted radioligand therapy.
Dr. Tang emphasized the clinical implications of these findings: “Our data validate RET as a selective surface marker unique to neuroendocrine prostate cancer, enabling both superior imaging and effective radioligand therapy in preclinical models. This research lays the groundwork for translating a RET-targeted theranostic approach into clinical settings, especially for patients whose tumors are PSMA-negative and thus poorly served by current imaging and therapeutic modalities.” The ability to precisely visualize and treat NEPC could markedly improve patient outcomes by facilitating earlier and more accurate disease management.
Currently, the research team is advancing toward first-in-human imaging trials under an investigator-initiated protocol, signaling a pivotal step in the translational pathway. This phase will ascertain critical parameters such as dosimetry, safety, and optimal imaging windows. Wider clinical adoption of RET-targeted theranostics will require robust validation in larger cohorts, rigorous safety evaluations, and regulatory approvals. Nonetheless, these early results herald a promising new paradigm for tackling a cancer subtype that has long defied conventional molecular targeting strategies.
The impact of this theranostic innovation extends beyond neuroendocrine prostate cancer. It elucidates a framework for identifying and exploiting unique biomarkers in other aggressive, treatment-resistant cancers that escape routine diagnostic detection. By integrating precision molecular imaging with targeted radiotherapy, this approach exemplifies the evolving field of personalized medicine, wherein diagnostic and therapeutic interventions are tailor-made to the molecular fingerprint of an individual’s tumor.
Moreover, the successful application of peptide ligands as vectors for both imaging and therapy underscores the versatility of peptide chemistry in nuclear medicine. Their small size, rapid systemic kinetics, and high specificity make peptides excellent candidates for theranostic development, as exemplified by RET-L7. These characteristics translate to superior imaging contrast, minimized off-target toxicity, and effective tumor eradication, synergistically enhancing diagnostic confidence and therapeutic efficacy.
The potential clinical benefits are profound. Patients with NEPC face a dismal prognosis due partly to diagnostic challenges that delay treatment initiation. The novel RET-targeted PET tracer offers a lifeline by illuminating tumors previously obscured by the limitations of PSMA imaging. Coupled with targeted radioligand therapy, clinicians could simultaneously pinpoint, treat, and monitor tumor response with unprecedented precision, ultimately elevating standards of care.
In summary, the identification and validation of RET as a selective biomarker for neuroendocrine prostate cancer, combined with the engineering of RET-binding peptides for PET imaging and radioligand therapy, represent a monumental stride forward in nuclear medicine. This theranostic approach circumvents the shortcomings of PSMA-directed strategies, offering new hope for patients afflicted by one of the most lethal prostate cancer variants. As the research progresses toward clinical application, it underscores the power of molecular insight combined with cutting-edge imaging and therapeutic technologies in transforming cancer care.
Subject of Research: Neuroendocrine Prostate Cancer Theranostics Targeting RET Biomarker
Article Title: RET-Targeted Theranostic Peptides Enable PET Imaging and Radioligand Therapy of Neuroendocrine Prostate Cancer
News Publication Date: 2026
Web References:
- Society of Nuclear Medicine and Molecular Imaging 2026 Annual Meeting Abstract: https://www.xcdsystem.com/snmmi/program/UtDKfSi/index.cfm?pgid=3058&sid=53916&mobileappid=5391600000
- Society of Nuclear Medicine and Molecular Imaging: http://www.snmmi.org/
References: Tang Y, Xiao L, Yang J, Hu S, Rominger A, Shi K. RET-Targeted Theranostic Peptides Enable PET Imaging and Radioligand Therapy of Neuroendocrine Prostate Cancer. Presented at SNMMI 2026.
Image Credits: Courtesy of SNMMI
Keywords: Neuroendocrine prostate cancer, RET biomarker, PET imaging, radioligand therapy, theranostics, [^68Ga]Ga-DOTA-RET-L7, [^177Lu]Lu-DOTA-RET-L7, PSMA-negative prostate cancer, molecular imaging, personalized medicine
