Essential Peer-Reviewed Reading in Kidney Cancer
The peer-reviewed articles summarized in this section were selected by the Guest
Editor, Brian M. Shuch, MD, for their timeliness, importance, relevance, and potential
impact on clinical practice or translational research. Updated October 2018.
Sunitinib alone or after nephrectomy in metastatic renal-cell carcinoma. Méjean A, Ravaud A, Thezenas S, et al. N Engl J Med. 2018 Aug 2; doi: 10.1056/NEJMoa 1803675.
Summary: Cytoreductive nephrectomy has been the standard of care in metastatic renal-cell carcinoma for 20 years, supported by randomized trials and large, retrospective studies. However, the efficacy of targeted therapies has challenged this standard. This phase 3 trial randomly assigned, in a 1:1 ratio, patients with confirmed metastatic clear-cell renal-cell carcinoma at presentation who were suitable candidates for nephrectomy to undergo nephrectomy and then receive sunitinib (standard therapy) or to receive sunitinib alone. Randomization was stratified according to prognostic risk (intermediate or poor) in the Memorial Sloan Kettering Cancer Center prognostic model. Patients received sunitinib at a dose of 50 mg daily in cycles of 28 days on and 14 days off every 6 weeks. The primary end point was overall survival. A total of 450 patients were enrolled from September 2009 to September 2017. At interim analysis, the median follow-up was 50.9 months, with 326 deaths observed. The results in the sunitinib-alone group were noninferior to those in the nephrectomy-sunitinib group with regard to overall survival. Median overall survival was 18.4 months in the sunitinib-alone group and 13.9 months in the nephrectomy-sunitinib group. No significant differences in response rate or progression-free survival were observed. Adverse events were as anticipated in each group.
Conclusion: Sunitinib alone was not inferior to nephrectomy followed by sunitinib in patients with metastatic renal-cell carcinoma who were classified as having intermediate-risk or poor-risk disease.
VHL substrate transcription factor ZHX2 as an oncogenic driver in clear cell renal cell carcinoma. Zhang J, Wu T, Simon J, et al. Science. 2018 Jul 20;361 (6399):290-295.
Summary: Inactivation of the von Hippel-Lindau (VHL) E3 ubiquitin ligase protein is a hallmark of clear cell renal cell carcinoma (ccRCC). Identifying how pathways affected by VHL loss contribute to ccRCC remains challenging. A genome-wide in vitro expression strategy was used to identify proteins that bind VHL when hydroxylated. Zinc fingers and homeoboxes 2 (ZHX2) was found as a VHL target, and its hydroxylation allowed VHL to regulate its protein stability. Tumor cells from ccRCC patients with VHL loss-of-function mutations usually had increased abundance and nuclear localization of ZHX2.
Conclusion: Functionally, depletion of ZHX2 inhibited VHL-deficient ccRCC cell growth in vitro and in vivo. Mechanistically, integrated chromatin immunoprecipitation sequencing and microarray analysis showed that ZHX2 promoted nuclear factor κB activation. These studies reveal ZHX2 as a potential therapeutic target for ccRCC.
Validation of the 16-gene recurrence score in patients with locoregional, high-risk renal cell carcinoma from a phase III trial of adjuvant sunitinib. Rini BI, Escudier B, Martini JF, et al. Clin Cancer Res. 2018 Sep 15;24(18): 4407-4415.
Summary: Adjuvant sunitinib prolonged disease-free survival in patients with locoregional high-risk renal cell carcinoma (RCC) in the S-TRAC trial (ClinicalTrials.gov NCT00375674). The 16-gene Recurrence Score (RS) assay was previously developed and validated to estimate risk for disease recurrence in patients with RCC after nephrectomy. This analysis further validated the prognostic value of RS assay in patients from S-TRAC and explored the association of RS results with prediction of sunitinib benefit. The analysis was prospectively designed with prespecified genes, algorithm, endpoints, and analytical methods. Primary RCC was available from 212 patients with informed consent; primary analysis focused on patients with T3 RCC. Gene expression was quantitated by RT-PCR. Time to recurrence (TTR), DFS, and renal cancer-specific survival (RCSS) were analyzed using Cox proportional hazards regression. Baseline characteristics were similar between patients with and those without RS results, and between the sunitinib and placebo arms among patients with RS results. RS results predicted TTR, DFS, and RCSS in both arms, with the strongest results observed in the placebo arm. When high versus low RS groups were compared, HR for recurrence was 9.18 [95% confidence interval (CI), 2.15-39.24) in the placebo arm; interaction of RS results with treatment was not significant.
Conclusion: The strong prognostic performance of the 16-gene RS assay was confirmed in S-TRAC, and the RS assay is now supported by level IB evidence. RS results may help identify patients at high risk for recurrence who may derive higher absolute benefit from adjuvant therapy.
An empirical approach leveraging tumorgrafts to dissect the tumor microenvironment in renal cell carcinoma identifies missing link to prognostic inflammatory factors. Wang T, Lu R, Kapur P, et al. Cancer Discov. 2018 Sep;8(9):1142-1155.
Summary: By leveraging tumorgraft (patient-derived xenograft) RNA-sequencing data, an empirical approach, DisHet, was able to dissect the tumor microenvironment (eTME). Using eTME, genomics, pathology, and medical record data involving >1,000 patients, the study established an inflamed pan-RCC subtype (IS) enriched for regulatory T cells, natural killer cells, TH1 cells, neutrophils, macrophages, B cells, and CD8+ T cells. IS is enriched for aggressive RCCs, including BAP1-deficient clear-cell and type 2 papillary tumors. The IS subtype correlated with systemic manifestations of inflammation such as thrombocytosis and anemia, which are enigmatic predictors of poor prognosis. Furthermore, IS was a strong predictor of poor survival. The analyses suggest that tumor cells drive the stromal immune response. These data provide a missing link between tumor cells, the TME, and systemic factors.
Conclusion: the authors undertook a novel empirical approach to dissect the RCC TME by leveraging tumorgrafts. The dissection and downstream analyses uncovered missing links between tumor cells, the TME, systemic manifestations of inflammation, and poor prognosis.
The classification of pediatric and young adult renal cell carcinomas registered on the children’s oncology group (COG) protocol AREN03B2 after focused genetic testing. Cajaiba MM, Dyer LM, Geller JI, et al. Cancer. 2018 Aug;124(16):3381-3389.
Summary: Renal cell carcinomas (RCCs) are rare in young patients. Knowledge of their pathologic and molecular spectrum remains limited, and no prospective studies have been performed to date in this population. This study analyzed patients diagnosed with RCC who were prospectively enrolled in the AREN03B2 Children’s Oncology Group (COG). The objective was to classify these tumors with the aid of focused genetic testing and to characterize their features. All tumors registered as RCC by central review were retrospectively re-reviewed and underwent additional ancillary studies. Tumors were classified according to the 2016 World Health Organization classification system when possible. In total, 212 tumors were identified, and these were classified as microphthalmia transcription factor (MiT) translocation RCC (MiT-RCC) (41.5%), papillary RCC (16.5%), renal medullary carcinoma (12.3%), chromophobe RCC (6.6%), clear cell RCC (3.3%), fumarate hydratase-deficient RCC (1.4%), and succinate dehydrogenase-deficient RCC (0.5%). Other subtypes included tuberous sclerosis-associated RCC (4.2%), anaplastic lymphoma kinase (ALK)-rearranged RCC (3.8%), thyroid-like RCC (1.4%), myoepithelial carcinoma (0.9%), and unclassified (7.5%). MiT-RCCs were classified as either transcription factor E3 (TFE3) (93.2%) or EB (TFEB) (6.8%) translocations, and characterization of fusion partners was possible in most tumors.
Conclusion: The current study delineates the frequency of distinct RCC subtypes in a large prospective series of young patients and contributes knowledge to the diagnostic, clinical, and genetic features of MiT-RCC, the most common subtype among this age group. The identification of rare subtypes expands the spectrum of RCC in young patients, supporting the need for a thorough diagnostic workup. These studies may aid in the introduction of specific therapies for different RCC subtypes in the future.
Prevalence of germline mutations in cancer susceptibility genes in patients with advanced renal cell carcinoma. Carlo MI, Mukherjee S, Mandelker D, et al. JAMA Oncol. 2018 Sep 1;4(9):1228-1235.
Summary: The prevalence of cancer-related germline mutations in patients with advanced RCC and the phenotypes associated with some rare mutations are unknown. This study examined the prevalence of germline mutations in both known RCC predisposition genes and other cancer-associated genes and to identify clinical and pathologic factors associated with germline mutations. In this 2-year cohort study, 254 of 267 patients with advanced (American Joint Committee on Cancer stage III or IV) RCC who were seen in medical oncology or urology clinics agreed to germline sequencing and disclosure of results. Mutation prevalence and spectrum in patients with advanced RCC were determined. Clinical characteristics were assessed by mutation status. Of the 254 patients (median age [range], 56 [13-79] years; 179 [70.5%] male; 211 [83.1%] non-Hispanic white), germline mutations were identified in 41 (16.1%); 14 (5.5%) had mutations in syndromic RCC-associated genes (7 in FH, 3 in BAP1, and 1 each in VHL, MET, SDHA, and SDHB). The most frequent mutations were CHEK2 (n = 9) and FH (n = 7). Of genes not previously associated with RCC risk, CHEK2 was overrepresented in patients compared with the general population, with an odds ratio of RCC of 3.0 ( P = .003). Patients with non-clear cell RCC were significantly more likely to have an RCC-associated gene mutation (9 [11.7%] of 74 vs 3 [1.7%] of 177), and 8 (10.0%) had a mutation in a gene that could guide therapy. Of patients with mutations in RCC-associated genes, 5 (35.7%) failed to meet current clinical guidelines for genetic testing.
Conclusion: Of patients with non-clear cell RCC, more than 20% had a germline mutation, of which half had the potential to direct systemic therapy. Current referral criteria for genetic testing did not identify a substantial portion of patients with mutations, supporting the role of a more inclusive sequencing approach.
KIM-1 as a blood-based marker for early detection of kidney cancer: a prospective nested case-control study. Scelo G, Muller DC, Riboli E, et al. Clin Cancer Res. 2018 Jul 23. doi: 10.1158/1078-0432.CCR-18-1496.
Summary: Kidney injury molecule-1 (KIM-1) has been shown to be elevated in the plasma of RCC patients. This study tested whether plasma KIM-1 could represent a means of detecting RCC prior to clinical diagnosis. KIM-1 concentrations were measured in prediagnostic plasma from 190 RCC cases and 190 controls nested within a population-based prospective cohort study. Cases had entered the cohort up to 5 years before diagnosis, and controls were matched on cases for date of birth, date at blood donation, sex, and country. The incidence rate ratio (IRR) of RCC for a doubling in KIM-1 concentration was 1.71, corresponding to an IRR of 63.3, comparing the 80th to the 20th percentiles of the KIM-1 distribution in this sample. Compared with a risk model including known risk factors of RCC (age, sex, country, body mass index, and tobacco smoking status), a risk model additionally including KIM-1 substantially improved discrimination between cases and controls. High plasma KIM-1 concentrations were also associated with poorer survival.
Conclusion: Plasma KIM-1 concentrations could predict RCC incidence up to 5 years prior to diagnosis and were associated with poorer survival. KCJ