AR-2 fluorescence <i>in vivo</i> correlates with ATX levels.

<p>(<b>a</b>) A mouse bearing an MDA-MB-231 orthotopic tumor (arrow) was injected with AR-2 by tail vein injection and NIRF was imaged. (<b>b</b>) AR-2 tumor-bearing mice similar to (a), or bearing an MDA-MB-435 orthotopic tumor were imaged and <i>in vivo</i> tumor fluorescence was determined (n = 11 for MDA-MB-231 or n = 3 for MDA-MB-435). Tumors were then excised and ATX levels were measured in tumor homogenates by ELISA. The data were plotted as tumor fluorescence versus ATX mass and fit using linear regression analysis. The slope of the resulting line demonstrates significant correlation (p<0.0001).