[Abstract unavailable

Background: High tumor mutation burden (TMB-H) has been proposed as a predictive biomarker for response to immune checkpoint blockade (ICB), largely due to the potential for tumor mutations to generate immunogenic neoantigens. Despite recent pan-cancer approval of ICB treatment for any TMB-H tumor, as assessed by the targeted FoundationOne CDx assay in nine tumor types, the utility of this biomarker has not been fully demonstrated across all cancers. Patients and methods: Data from over 10 000 patient tumors included in The Cancer Genome Atlas were used to compare approaches to determine TMB and identify the correlation between predicted neoantigen load and CD8 T cells. Association of TMB with ICB treatment outcomes was analyzed by both objective response rates (ORRs, N ¼ 1551) and overall survival (OS, N ¼ 1936). Results: In cancer types where CD8 T-cell levels positively correlated with neoantigen load, such as melanoma, lung, and bladder cancers, TMB-H tumors exhibited a 39.8% ORR to ICB [95% confidence interval (CI) 34.9-44.8], which was significantly higher than that observed in low TMB (TMB-L) tumors [odds ratio (OR) ¼ 4.1, 95% CI 2.9-5.8, P < 2 Â 10 À16 ]. In cancer types that showed no relationship between CD8 T-cell levels and neoantigen load, such as breast cancer, prostate cancer, and glioma, TMB-H tumors failed to achieve a 20% ORR (ORR ¼ 15.3%, 95% CI 9.2-23.4, P ¼ 0.95), and exhibited a significantly lower ORR relative to TMB-L tumors (OR ¼ 0.46, 95% CI 0.24-0.88, P ¼ 0.02). Bulk ORRs were not significantly different between the two categories of tumors (P ¼ 0.10) for patient cohorts assessed. Equivalent results were obtained by analyzing OS and by treating TMB as a continuous variable. Conclusions: Our analysis failed to support application of TMB-H as a biomarker for treatment with ICB in all solid cancer types. Further tumor type-specific studies are warranted.

The treatment of renal cell carcinoma (RCC) has changed greatly over the past 15 years. Progress in the surgical management of the primary tumor and increased understanding of the molecular biology and genomics of the disease have led to the development of new therapeutic agents. The management of the primary tumor has changed owing to the realization that clean margins around the primary lesion are sufficient to prevent local recurrence, as well as the development of more sophisticated tools and techniques that increase the safety of partial nephrectomy. The management of advanced disease has altered even more dramatically as a result of new agents that target the tumor vasculature or that attenuate the activation of intracellular oncogenic pathways. This review summarizes data from prospective randomized phase III studies on the surgical management and systemic treatment of RCC, and provides an up to date summary of the histology, genomics, staging, and prognosis of RCC. It describes the management of the primary tumor and offers an overview of systemic agents that form the mainstay of treatment for advanced disease. The review concludes with an introduction to the exciting new class of immunomodulatory agents that are currently in clinical trials and may form the basis of a new therapeutic approach for patients with advanced RCC.

Antiangiogenic therapy resistance occurs frequently in patients with metastatic renal cell carcinoma (RCC). The purpose of this study was to understand the mechanism of resistance to sunitinib, an antiangiogenic small molecule, and to exploit this mechanism therapeutically. We hypothesized that sunitinib-induced upregulation of the prometastatic MET and AXL receptors is associated with resistance to sunitinib and with more aggressive tumor behavior. In the present study, tissue microarrays containing sunitinib treated and untreated RCC tissues were stained with MET and AXL antibodies. The low malignant RCC cell line, 786-O, was chronically treated with sunitinib, and assayed for AXL, MET, epithelial mesenchymal transition (EMT) protein expression and activation. Co-culture experiments were used to examine the effect of sunitinib pretreatment on endothelial cell growth. The effects of AXL and MET were evaluated in various cell-based models by shRNA or inhibition by cabozantinib, the multi-tyrosine kinases inhibitor that targets VEGFR, MET and AXL. Xenograft mouse models tested the ability of cabozantinib to rescue sunitinib resistance. We demonstrated that increased AXL and MET expression was associated with inferior clinical outcome in patients. Chronic sunitinib treatment of RCC cell lines activated both AXL and MET, induced EMT associated gene expression changes including upregulation of Snail and β-catenin, and increased cell migration and invasion. Pretreatment with sunitinib enhanced angiogenesis in 786-0/HUVEC co-culture models. The suppression of AXL or MET expression, and the inhibition of AXL and MET activation using cabozantinib both impaired chronic sunitinib treatment-induced prometastatic behavior in cell culture, and rescued acquired resistance to sunitinib in xenograft models. In summary, chronic sunitinib treatment induces the activation of AXL and MET signaling and promotes pro-metastatic behavior and angiogenesis. The inhibition of AXL and MET activity may overcome resistance induced by prolonged sunitinib therapy in metastatic RCC.

No abstract