(UroToday.com) One mainstay of treatment in advanced renal cell carcinoma are tyrosine kinase inhibitors against multiple signaling pathways active in this disease. Paradoxically, molecular profiling is not routinely used prior to initiation of treatment in RCC. In the past few years, multiple efforts have been undertaken to determine predictive molecular biomarkers associated with response to treatment in RCC. These have largely utilized archived biopsy or tissue specimens, which provide valuable information. However, these are difficult to obtain in a serial fashion with treatment and therefore do not necessarily provide temporal information of tumor evolution.