Detection and Treatment of Ovarian Cancer by Targeting Tumor Extracellular Hydroxyapatite: A New Paradigm

In this report, we continue to evaluate tumor extracellular hydroxyapatite (HAP), Ca10(PO4)6OH2, as an imaging biomarker of ovarian cancer a target for therapy. We have shown that HAP-binding radiotracers such as FDA-approved 18F-NaF can be used with PET imaging and 99mTc-MDP with SPECT imaging to detect breast tumors; in this context, detection of tumor-associated HAP exhibited high specificity and a high signal-to background ratio (SBR) as HAP is absent in normal soft tissue. In ovarian cancer, conventional imaging modalities lack clear metrics for assessing tumor burden before and after surgical debulking and for assessing tumor response to therapy. This is mainly due to lack of specificity and/or low SBR ratio from standard imaging. Additionally, we had developed a nanoparticulate sulfonated polystyrene solution (NSPS) to break-up HAP in vivo inducing a localized alkalosis status in the tumor microenvironment inhibiting tumor growth.