The goal of this K24 is to allow the principal investigator (PI) to pursue clinical research in medical oncology and mentor new investigators. The PI's current program identifies new treatment programs for patients with genito-urinary malignancies, specifically testicular cancer and renal cell carcinoma (RCC). Germ cell tumor (GCT) of the testis is considered a model for the curable cancer, with 70 percent of patients with advanced GCT cured by cisplatin-combination chemotherapy. However, the 30 percent of patients with resistant GCT require more effective therapy. Research efforts focus on inclusion of dose-intensive therapy in first-line treatment for patients predicted as resistant, novel means of dose-intensification, and the identification of new agents with antitumor effect which are incorporated into combination therapy. In contrast, RCC represents the most resistant malignancy to chemotherapy. Biological agents, i.e. interferon-alpha, show a low degree of activity. Efforts against RCC are directed at the study of treatment programs to augment the activity of interferon and the study of novel agents for antitumor activity. During the past 10 years, the PI has conducted 23 phase I,II and III prospective Instituitional Reveiw Board-approved clinical trials. For both tumors, a clinical database has been established to identify prognostic factors and direct therapy. Participation in translational research is fundamental for my research effort as a clinical investigator. In the PI's position as Associate Chairman, Clinical Trials, Department of Medicine, the PI oversees the Clinical Trials Office, which is comprised of 50 research assistants and is responsible for process and data management of all clinical trials in the Department. Bringing the impact of this position to bear in an active clinical trial program in GCT and RCC creates a unique opportunity as a comprehensive learning experience for medical oncology fellows in teaching clinical trial methodology. Access to a cadre of fellows-in-training at our center makes this possible. Education in clinical trial methodology is given by direct supervision and teaching in a one-to-one basis in the clinic, through tutoring, and in conference. Skills of clinical trial conduct such as writing protocols, obtaining informed consent, response and toxicity assessment, and analysis of data requires are emphasized. The PI has mentored 10 medical oncology fellows-in training during their second and third year of training; six are active in academic oncology and/or clinical investigator careers. One recently joined staff at MSKCC in the Genito-urinary Section. Mentoring of clinical trials is extended beyond fellowship to junior faculty members.