In a very narrowly defined context, there appear to be some markers that could potentially be viewed as known valid biomarkers. As noted above, however, a panel of biomarkers will likely be required to characterize nephrotoxicity rather than a single ideal biomarker. A panel will be necessary in particular to specify different localizations in the kidney and to differentiate among toxicity types. While Novartis and the PSTC have not yet achieved this capability, their ultimate goal is to assemble a collection of kidney toxicity markers that will be visible prior to histopathological changes and can serve as a panel covering most nephrotoxicity.