In this study, glycosaminoglycan (GAG) profiling in subjects diagnosed with metastatic renal cell carcinoma (mRCC) is hypothesized to be useful in monitoring drug response and predict radiological response. To this end, glycosaminoglycan scores based on longitudinal samples of plasma and urine in prospectively enrolled patients will be correlated to radiological response to first-line therapy based on current standard-of-care. A positive correlation indicates that glycosaminoglycan scores can successfully detect patients that are not responding to treatment before the scheduled follow-up in which radiological imaging is performed. Data on the extent of metastasis (number of metastatic sites) will be collected to assess whether glycosaminoglycans correlate accordingly.

Inclusion Criteria:

• Eastern Cooperative Oncology Group (ECOG) performance status 0-2
• Diagnosis of renal cell carcinoma
• Metastatic disease
• Predicted life expectancy over 2 months
• Patient referred for first line drug therapy
• Standard imaging evaluation 12 weeks prior to inclusion
• Planned for standard imaging within 16 weeks after start of therapy
• Informed consent

Exclusion Criteria:

• Lack of proper compliance to accept continuous samplings

Untreated patients with diagnosis of metastatic renal cell carcinoma referred for first line treatment.

Data will be accessible upon study publication