Glycosaminoglycans (GAGs) were significantly altered in localized as well advanced RCC compared to healthy samples. In addition, GAG scores correlated with progression-free survival and overall survival (OS) in a prospective cohort of patients with metastatic ccRCC and localized RCC. However, it is still unknown whether alterations in plasma and urine GAGs are exquisitely specific to RCC or are shared by other benign lesions in the kidney, such as angiomyolipomas, oncocytomas, or PEComa.

Inclusion Criteria:

1. Patients who underwent CT-scan with suspicion of renal tumor and the scans show no sign of renal cancer.
2. For patient with ccRCC or oncocytoma, they should have a histological verified tumor (Biopsy or surgical specimen)
3. Sign up information consent
4. Can perform protocol procedure

Exclusion Criteria:

1. Non-clear cell Renal cell carcinoma
2. RCC with pure sarcomatoid differentiation, also called sarcoma of the kidney
3. Use of heparin for concurrent disease in need of blood dilution (e.g. ongoing deep vein thrombosis or lung emboli). Note: use of of heparin for thrombus prophylaxis in conjunction with primary surgery or postoperatively ≤4 weeks will be allowed.

All patients referred to our department by family doctors or the primary sector with a suspicion of renal tumor by CT-scanning will be asked to participate in the study. Patients with suspected small renal tumor will be offered renal tumor biopsies as standard procedure.