Renal cell carcinoma (RCC) presents as metastatic disease in one third of cases. Research on circulating tumor cells (CTCs) and liquid biopsies is improving the understanding of RCC biology and metastases formation. However, a standardized, sensitive, specific, and cost-effective CTC detection technique is lacking. The use of platforms solely relying on epithelial markers is inappropriate in RCC due to the frequent epithelial-mesenchymal transition that CTCs undergo. This study aimed to test and clinically validate RUBYchip™, a microfluidic label-free CTC detection platform, in RCC patients. The average CTC capture efficiency of the device was 74.9% in spiking experiments using three different RCC cell lines. Clinical validation was performed in a cohort of 18 patients, eight non-metastatic (M0), five metastatic treatment-naïve (M1TN), and five metastatic progressing-under-treatment (M1TP). An average CTC detection rate of 77.8% was found and the average (range) total CTC count was 6.4 (0–27), 101.8 (0–255), and 3.2 (0–10), and the average mesenchymal CTC count (both single and clustered cells) was zero, 97.6 (0–255), and 0.2 (0–1) for M0, M1TN, and M1TP, respectively. CTC clusters were detected in 25% and 60% of M0 and M1TN patients, respectively. These results show that RUBYchip™ is an effective CTC detection platform in RCC.

Background: Circulating tumor cells (CTCs) may be the missing renal cell carcinoma (RCC) biomarker. No-touch (NT) resection has shown benefit in several tumors. Methods: A randomized controlled trial comparing CTC and circulating mesenchymal cell (CMC) release in no-touch (NT) vs. conventional (C) laparoscopic RN. Blood samples were collected at operation room arrival (S0), specimen extraction (S1), postoperative D1, and D30. CTCs were isolated and analyzed using RUBYchip™. Results: Thirty-four patients were included. No significant differences were found between groups in CTC and CMC counts, count variations between time points, complications, and survival. The total circulating cell detection rates in the NT, C, and overall RCC groups were 58.3%, 80.0%, and 70.4% at S0; 41.6%, 86.7%, and 66.7% at S1; 50.0%, 64.3%, and 60.0% at D1; and 54.5%, 42.9%, and 44.0% at D30, respectively. A progressive decrease in CMCs was observed in the C group after surgery, especially at D1 (4.78 to 1.64 CMCs/7.5 mL blood, p = 0.035). Healthy controls had no circulating cells; however, high CMC counts were found in chronic inflammation controls and oncocytoma patients, with no significant difference from RCC patients (p = 0.460). Conclusions: NT RN did not reduce circulating cell release nor improve survival compared to C RN.