Engraftment of Tumorgrafts Predicts for Development of Metastasis in Patients with Localized Renal Cell Carcinoma

PURPOSE: This retrospective study compares tumorgraft engraftment with development of metastatic renal cell carcinoma (RCC) in patients after the resection of localized tumor in order to determine the potential clinical applications of tumorgraft models. MATERIALS AND METHODS: We analyzed tumorgraft lines derived from primary tumor samples of 180 patients. Odds ratios and Kaplan-Meier analyses were used to determine the correlation between tumor engraftment and patient outcome. RESULTS: There were primary tumor samples from a total of 22 patients who had metastatic disease at the time of surgery. These tumors engrafted at a higher frequency than those of patients who did not have metastatic disease at the time of surgery (OR=3.39, p=0.0099). Of the 158 patients who had localized RCC at the time of surgery, patients whose tumors engrafted developed metastasis at a higher frequency (OR=3.53, p=0.01174) than those whose tumors did not engraft. Patients with engrafted tumors also had a marked decrease in progression-free survival and RCC-specific progression-free survival, but not overall survival. CONCLUSIONS: Engraftment of tumors in mice may be an independent predictor of patient outcome and thus has the potential to become a powerful clinical tool. It also may provide an experimental system to dissect determinants of metastases. Finally, selecting tissue from patients with metastatic RCC at the time of surgery can be used to increase the efficiency of engraftment in RCC tumorgraft models.