Real-Time Transferrin-Based PET Detects MYC-Positive Prostate Cancer

• Published in: Molecular cancer research 2017-09, Vol.15 (9), p.1221-1229
• Main Authors: Aggarwal, Rahul, Behr, Spencer C, Paris, Pamela L, Truillet, Charles, Parker, Matthew F L, Huynh, Loc T, Wei, Junnian, Hann, Byron, Youngren, Jack, Huang, Jiaoti, Premasekharan, Gayatri, Ranatunga, Nimna, Chang, Emily, Gao, Kenneth T, Ryan, Charles J, Small, Eric J, Evans, Michael J
• Format: Article
• Language: English
• Subjects: Biomarkers; Biopsy; Cancer; Castration; Cell culture; Citric acid; Copy number; Deoxyribonucleic acid; DNA; Genes, myc - genetics; Humans; Hyperactivity; Invasiveness; Male; Metastases; Molecular modelling; Myc protein; Patients; Positron emission; Positron-Emission Tomography - methods; Prostate cancer; Prostatic Neoplasms - genetics; Signaling; Target recognition; Tomography; Transferrin; Transferrin - metabolism; Tumors
• ISSN: 1541-7786; 1557-3125
• DOI: 10.1158/1541-7786.MCR-17-0196

Noninvasive biomarkers that detect the activity of important oncogenic drivers could significantly improve cancer diagnosis and management of treatment. The goal of this study was to determine whether Ga-citrate (which avidly binds to circulating transferrin) can detect MYC-positive prostate cancer tumors, as the transferrin receptor is a direct MYC target gene. PET imaging paired with Ga-citrate and molecular analysis of preclinical models, human cell-free DNA (cfDNA), and clinical biopsies were conducted to determine whether Ga-citrate can detect MYC-positive prostate cancer. Importantly, Ga-citrate detected human prostate cancer models in a MYC-dependent fashion. In patients with castration-resistant prostate cancer, analysis of cfDNA revealed that all patients with Ga-citrate avid tumors had a gain of at least one copy number. Moreover, biopsy of two PET avid metastases showed molecular or histologic features characteristic of MYC hyperactivity. These data demonstrate that Ga-citrate targets prostate cancer tumors with MYC hyperactivity. A larger prospective study is ongoing to demonstrate the specificity of Ga-citrate for tumors with hyperactive MYC. Noninvasive measurement of MYC activity with quantitative imaging modalities could substantially increase our understanding of the role of MYC signaling in clinical settings for which invasive techniques are challenging to implement or do not characterize the biology of all tumors in a patient. Moreover, measuring MYC activity noninvasively opens the opportunity to study changes in MYC signaling in patients under targeted therapeutic conditions thought to indirectly inhibit MYC. .