BACKGROUNDIntratumoral heterogeneity presents a major obstacle to the widespread implementation of precision medicine. The authors assessed the origin of intratumoral heterogeneity in nonseminomatous germ cell tumor of the testis (NSGCT) and identified distinct tumor subtypes and a potentially lethal phenotype.METHODSIn this retrospective study, all consecutive patients who had been diagnosed with an NSGCT between January 2000 and December 2010 were evaluated. The histologic makeup of primary tumors and the clinical course of disease were determined for each patient. A Fine and Gray proportional hazards regression analysis was used to determine the prognostic risk factors, and the Gray test was used to detect differences in the cumulative incidence of cancer death. In a separate prospective study, next‐generation sequencing was performed on tumor samples from 9 patients to identify any actionable mutations.RESULTSSix hundred fifteen patients were included in this study. Multivariate analysis revealed that the presence of yolk sac tumor in the primary tumor (P = .0003) was associated with an unfavorable prognosis. NSGCT could be divided into 5 subgroups. Patients in the yolk sac‐seminoma subgroup had the poorest clinical outcome (P = .0015). These tumors tended to undergo somatic transformation (P < .0001). Among the 9 NSGCTs that had a yolk sac tumor phenotype, no consistent gene mutation was detected.CONCLUSIONSThe current data suggest that intratumoral heterogeneity is caused in part by differentiation of pluripotent progenitor cells. Integrated or multimodal therapy may be effective at addressing intratumoral heterogeneity and treating distinct subtypes as well as a potentially lethal phenotype of NSGCT. Cancer 2016;122:1836–43. © 2016 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Although mortality from prostate cancer has declined over the past 20 years as a result of early detection and treatment, the 5-year survival rate for men with prostate cancer who develop metastatic disease is only 29%. Current treatment options for metastatic castration-recurrent prostate cancer (mCRPC) are associated with toxicity and a limited durable response; therefore, additional lines of efficacious and minimally toxic therapy are needed. Olaparib, a poly(adenosine 5'-diphosphate) ribose polymerase (PARP) inhibitor, received a U.S. Food and Drug Administration breakthrough therapy designation in January 2016 for the treatment of patients with BRCA1/2 or ATM gene-mutated mCRPC based on results of a compelling phase II trial of olaparib in patients with advanced castration-resistant prostate cancer (TOPARP-A). This study found that men with mCRPC and genetic mutations in DNA damage repair genes had an overall response rate of nearly 90% with olaparib treatment. In this review, we describe current therapies for mCRPC, the rationale for anti-PARP therapies, the pharmacology of olaparib for prostate cancer, clinical trials of olaparib for mCRPC, our clinical experience with olaparib for prostate cancer at a comprehensive cancer center, and future directions of olaparib for the treatment of mCRPC. Olaparib may constitute a promising treatment to prolong survival in patients with mCRPC, with an acceptable adverse effect profile. As the role of PARP inhibition in prostate cancer and other malignancies becomes further elucidated, olaparib may be shown to be beneficial for other patient populations.

A high incidence of proteinuria with minor severity within each class was demonstrated. It may be reasonable to continue therapy at the same dose for Grade 1 or 2 proteinuria. Treatment modification or discontinuation of therapy may be warranted with Grade 3 or 4 proteinuria.

390 Background: Cancer is a heterogeneous disease. Studying cancer heterogeneity may enable us to elucidate the various subtypes of a particular cancer, and improve the diagnosis, prognostication, and therapy of cancer. Nonseminomatous germ cell tumor (NSGCT) is a prime example of a heterogeneous disease. We determined potential lethality of NSGCT by characterizing the histological makeup of primary testicular tumors, the tumor burden, psychosocial issues, and surgical factors. Methods: From November 1997 to October 2012, 142 consecutive patients diagnosed with a NSGCT of the testis were evaluated for this study. The log-rank test was used to identify prognostic factors in univariate Kaplan-Meier analysis. A multivariate Cox regression model was used to evaluate predictive factors for overall survival. Results: Patient and tumor characteristics: median (range) age 25 (12 to 53); pathology – embryonal carcinoma 15%, teratoma 6%, and mixed NSGCT 79%; stage – I 46%, II 32%, and III 21%. Ten (7%) patients died from their NSGCT. Seven (5%) patients had incurable NSGCT. Multivariate analysis showed that presence of seminoma (p=0.007), presence of yolk sac tumor (p=0.019), clinical stage (p=0.027), and psychosocial issues (p=0.04), have unfavorable prognostic significance. Conclusions: Certain subtypes of NSGCT containing yolk sac tumor and seminoma are inherently chemotherapy resistant and potentially lethal. Psychosocial factors can delay the diagnosis and treatment of patients with such tumors and adversely affect their clinical outcome. Results of this study need to be validated in another data base or a prospective clinical trial.