The pressure towards innovation and creation of new model systems in regenerative medicine and cancer research has fostered the development of novel potential therapeutic applications. Kidney injuries provoke a high request of organ transplants making it the most demanding system in the field of regenerative medicine. Furthermore, renal cancer frequently threaten patients’ life and aggressive forms still remain difficult to treat. Ethical issues related to the use of embryonic stem cells, has fueled research on adult, patient-specific pluripotent stem cells as a model for discovery and therapeutic development, but to date, normal and cancerous renal experimental models are lacking. Several research groups are focusing on the development of organoid cultures. Since organoids mimic the original tissue architecture in vitro, they represent an excellent model for tissue engineering studies and cancer therapy testing. We established normal and tumor renal cell carcinoma organoids previously maintained in a heterogeneous multi-clone stem cell-like enriching medium. Starting from adult normal kidney specimens, we were able to isolate and propagate organoid 3D-structures composed of both differentiated and undifferentiated cells while expressing nephron specific markers. Furthermore, we were capable to establish organoids derived from cancer tissues although with a success rate inferior to that of their normal counterpart. Cancer cultures displayed epithelial and mesenchymal phenotype while retaining tumor specific markers. Of note, tumor organoids recapitulated neoplastic masses when orthotopically injected into immunocompromised mice. Our data suggest an innovative approach of long-term establishment of normal- and cancer-derived renal organoids obtained from cultures of fleshly dissociated adult tissues. Our results pave the way to organ replacement pioneering strategies as well as to new models for studying drug-induced nephrotoxicity and renal diseases. Along similar lines, deriving organoids from renal cancer patients opens unprecedented opportunities for generation of preclinical models aimed at improving therapeutic treatments.

While partial nephrectomy (PN) represents the standard surgical management for cT1 renal masses, its role for cT2 tumors is controversial. Robot-assisted PN (RAPN) is being increasingly implemented worldwide. To analyze perioperative, functional, and oncological outcomes of RAPN for cT2 tumors. Retrospective analysis of a large multicenter, multinational dataset of patients with nonmetastatic cT2 masses treated with robotic surgery (ROSULA: RObotic SUrgery for LArge renal mass). Robotic-assisted PN. Patients' demographics, lesion characteristics, perioperative variables, renal functional data, pathology, and oncological data were analyzed. Univariable and multivariable regression analyses assessed the relationships with the risk of intra-/postoperative complications, recurrence, and survival. A total of 298 patients were analyzed. Median tumor size was 7.6 (7-8.5) cm. Median RENAL score was 9 (8-10). Median ischemia time was 25 (20-32) min. Median estimated blood loss was 150 (100-300) ml. Sixteen patients had intraoperative complications (5.4%), whereas 66 (22%) had postoperative complications (5% were Clavien grade ≥3). Multivariable analysis revealed that a lower RENAL score (odds ratio [OR] 0.46, 95% confidence interval [CI] 0.21-0.65, p=0.02) and pathological pT2 stage (OR 0.51, 95% CI 0.12-0.86, p=0.001) were protective against postoperative complications. A total of 243 lesions (82%) were malignant. Twenty patients (8%) had positive surgical margins. Ten deaths and 25 recurrences/metastases occurred at a median follow-up of 12 (5-35) mo. At univariable analysis, higher pT stage was predictive of a likelihood of recurrences/metastases (p=0.048). While there was a significant deterioration of renal function at discharge, this remained stable over time at 1-yr follow-up. The main limitation of this study is its retrospective design. RAPN in the setting of select cT2 renal masses can safely be performed with acceptable outcomes. Further studies are warranted to corroborate our findings and to better define the role of robotic nephron sparing for this challenging indication. This report shows that robotic surgery can be used for safe removal of a large renal tumor in a minimally invasive fashion, maximizing preservation of renal function, and without compromising cancer control.