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Abstract #0501

Dual PI3K/mTOR Inhibition Suppresses Tumor PO2 Within Viable Tumor Assessed by 19F-MRI and Multispectral Analysis

Yunzhou Shi1, Jason Oeh2, Jeffrey Eastham-Anderson3, Sharon Yee2, David Finkle2, Franklin V. Peale3, Jed Ross1, Maj Hedehus1, Nicholas van Bruggen1, Rayna Venook2, Sarajane Ross2, Deepak Sampath2, Richard A. D. Carano4

1Biomedical Imaging, Genentech Inc.(Roche Group), South San Francisco, CA, United States; 2Translational Oncology, Genentech Inc.(Roche Group), South San Francisco, CA, United States; 3Pathology, Genentech Inc.(Roche Group), South San Francisco, CA, United States; 4Biomedical Imaging, Genentech, South San Francisco, CA, United States


The effect of a novel dual PI3K/mTOR inhibitor on tumor oxygen level was studied using a novel approach that combines 19F-MRI T1 mapping with diffusion-based multispectral K-means clustering. The current study aims to elucidate the role of PI3K/mTOR signaling on oxygen level in viable tumor. An anti-angiogenic agent, B20.4.1.1, was employed as a positive control for its known anti-vascular effects. We were able to monitor pO2 for 72h without fluorine signal loss. The current results advocate for the use of the multispectral 19F-MRI technique as a tool to better understand the mode of action of therapies that alter tumors microenvironment.