As can be seen from Fig. 8I and Additional file 3: Figure S3I, tissue and venous CTCs of patients with renal cancer can detect more mutated genes than arterial CTCs, the mutated genes targeted with clinically available drugs (KRAS exon3) were detected in tissues and arterial CTCs at the same time, the mutated genes (EGFR exon20) were detected in tissues, arterial CTCs and venous CTCs at the same time. The gene discussed is KRAS; the disease is renal carcinoma.