Individualized dosing with axitinib: rationale and practical guidance

Axitinib is a potent, selective, vascular endothelial growth factor receptor inhibitor with demonstrated efficacy as second-line treatment for metastatic renal cell carcinoma. Analyses of axitinib drug exposures have demonstrated high interpatient variability in patients receiving the 5 mg twice-daily (b.i.d.) starting dose. Clinical criteria can be used to assess whether individual patients may benefit further from dose modifications, based on their safety and tolerability data. This review provides practical guidance on the 'flexible dosing' method, to help physicians identify who would benefit from dose escalations, dose reductions or continuation with manageable toxicity at the 5 mg b.i.d. dose. This flexible approach allows patients to achieve the best possible outcomes without compromising safety.

Management of the small renal mass

The increasing use of cross-sectional imaging has led to an increase in the diagnosis of incidental small renal masses (SRMs). About 20% of such masses are benign, while a significant proportion of malignant SRMs demonstrate slow growth kinetics and non-aggressive histologic features. Given these characteristics, lesions that were traditionally treated surgically are increasingly managed with less aggressive approaches. Further contributing to the evolving management paradigm is accumulating evidence supporting the safety of active surveillance and the efficacy of percutaneous renal mass biopsy in guiding management decisions. This review first discusses the epidemiology and diagnostic work-up of SRMs. The available management options are then examined, with emphasis placed on the clinical factors considered in selecting an appropriate approach. The existing evidence and long-term outcomes of each strategy are discussed. Finally, an overview of the current paradigm for the management of a patient with a SRM is provided. The goal is to provide physicians with the necessary understanding to appropriately manage this increasingly common condition.

Abstract 5599: Soluble PD-L1 as a surrogate biomarker of metastatic progression and resistance to antiangiogenic therapy

Immune-checkpoint inhibitors are now approved for the treatment of early- and late-stage cancers. These include agents that block the T-cell regulatory protein programmed cell death 1 (PD-1) from being activated by the PD-1 ligand 1 (PD-L1) expressed on cancer cells. There is an urgent need to identify biomarkers of PD-1 pathway inhibition that would predict patient populations responsive to treatment and/or serve as surrogates for drug activity and resistance. PD-L1 expression on tumors is currently a biomarker candidate, but reliable detection and quantification methodologies have proven challenging to standardize. Recently, a soluble PD-L1 (sPD-L1) fragment was identified that can derive from cell-bound PD-L1. Retrospective clinical examinations of sPD-L1 levels in cancer patients suggest a potential use as a surrogate for disease progression and response to treatment; but few preclinical studies have been performed to test this predictive value. We undertook experiments to evaluate plasma sPD-L1 in mouse tumor models during localized primary tumor growth (after orthotopic cell implantation) and spontaneous metastatic disease progression (after surgical removal of the primary). Mouse syngeneic and human xenograft implantation models included breast, kidney, colon, and melanoma cell systems. Our results show that circulating plasma sPD-L1 can correlate with primary and metastatic progression in a stage and model specific manner. Next, we evaluated sPD-L1 following treatment with neutralizing antibodies to PD-1 and PD-L1 in tumor-free mice and found significant dose-dependent sPD-L1 increases, suggesting systemic changes may have utility as a measurement of target saturation and dosing independent of tumor growth. Finally, with current approvals of PD-1 inhibitors in renal cell carcinoma (RCC) patients previously treated with antiangiogenic agents that block vascular endothelial growth factor (VEGF), we evaluated plasma in mouse models of sunitinib resistance - a VEGF receptor tyrosine kinase inhibitor (RTKI). Our results demonstrate that VEGF pathway resistance yields changes in sPD-L1 and may be useful in predicting response to PD-1 pathway inhibition in the refractory setting. Together, these investigations suggest that circulating sPD-L1 changes during disease progression (both local and disseminated) may serve as a potential predictive biomarker for immune-checkpoint and antiangiogenic therapy.

Citation Format: Michalis Mastri, Amanda Tracz, Yuhao Shi, Georg Bjarnason, Tran Nguyen, Brian Rini, John M.L. Ebos. Soluble PD-L1 as a surrogate biomarker of metastatic progression and resistance to antiangiogenic therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5599. doi:10.1158/1538-7445.AM2017-5599

Abstract 3520: PBRM1 inactivation in renal cell cancer alters master transcription factor hub composition to repress instead of activate epithelial-differentiation

Clear cell renal cell cancers (RCC) universally inactivate PBRM1 (single allele deletion 100%, bi-allelic deletion/mutation ~40%), however, the mechanisms by which PBRM1 loss contributes to RCC-genesis are unknown. Of ~4000 genes consistently less expressed in RCC than normal renal cortex, >30% were kidney differentiation genes by gene ontology analysis, e.g., 394 (~10%) suppressed genes had specialized renal epithelial functions of cation transport, cell adhesion and excretion (TCGA). Suppression of hundreds of epithelial-differentiation genes suggested disruption to the core transcription factor circuit (protein network hub) activating this program. This master transcription factor hub contains PAX2, PAX8, GATA3 and LHX1, shown by murine knock-outs and human pedigrees with renal defects, and confirmed by our protein interactome studies. Of these master transcription factors, PAX2 and PAX8 expression was preserved in RCC compared to normal kidney, but downstream GATA3 and LHX1 expression was markedly decreased (2 to 4-fold) even though PAX8 localized at these target genes by chromatin immunoprecipitation - this suggested compromised PAX8 transcription activating function. PAX8 protein interactome in RCC cells indicated that PBRM1 is a PAX8 coactivator, and introduction of PBRM1 into PBRM1-haploinsufficient RCC cells (ACHN) by transfection increased activation of GATA3, WT1 and HNF4A, decreased MYC protein, increased p27/CDKN1B protein that mediates cell cycle exits by terminal differentiation, produced morphological changes of epithelial differentiation, and decreased proliferation. Coactivator versus corepressor recruitment by master transcription factors is a dynamic interchange, and the protein interactome studies indicated PBRM1 loss unbalanced stoichiometry of the PAX8-associated protein hub towards corepressors including DNMT1. Depletion of DNMT1 by non-cytotoxic concentrations of decitabine (0.5 µM) produced a remarkable shift from corepressors to coactivators in the PAX8 protein interactome, accompanied by terminal epithelial-differentiation as observed with PBRM1 reintroduction. Cell cycle exits by differentiation do not require p53/p16, and this effect was also produced in vivo in a subcutaneous xenograft model of TP53-mutated refractory/relapsed RCC, especially when decitabine in vivo pharmacology was optimized for non-cytotoxic DNMT1-depletion by avoiding a high Cmax and increasing its half-life and distribution into solid tissue, by administration of low dose in combination with an inhibitor of the enzyme cytidine deaminase that degrades decitabine. PBRM1 loss in RCC thus alters composition of a master transcription factor hub to repress instead of activate terminal epithelial-differentiation, an effect that can be reversed pharmacologically for novel, p53/p16-independent differentiation-restoring therapy.

Citation Format: Xiaorong Gu, Francis Enane, Reda Mahfouz, Tomas Radivoyevitch, Bartlomiej Przychodzen, Yvonne Parker, Daniel Lindner, Brian Rini, Yogen Saunthararajah. PBRM1 inactivation in renal cell cancer alters master transcription factor hub composition to repress instead of activate epithelial-differentiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3520. doi:10.1158/1538-7445.AM2017-3520

Change in Psoas Muscle Volume as a Predictor of Outcomes in Patients Treated with Chemotherapy and Radical Cystectomy for Muscle-Invasive Bladder Cancer

Objective: Sarcopenia, or the age-related loss of skeletal muscle mass and function, has been investigated as a potential marker of adverse outcomes among surgical patients. Our aim was to assess for changes in psoas muscle volume (PMV) following administration of neoadjuvant chemotherapy (NAC) in patients with bladder cancer and to examine whether changes in PMV following NAC are predictive of perioperative complications, pathologic response or survival.

Methods: During the period of 2009–2013, patients undergoing NAC and radical cystectomy (RC) at our institution with pre and post NAC cross sectional images available were included. Bilateral total psoas muscle volume (PMV) was obtained from pre- and post- NAC images and the proportion of PMV change was calculated by dividing the change PMV by pre-NAC PMV. Analyses for the assessment of factors predicting PMV loss, partial/complete pathologic response (pPR/pCR), complications, readmission, cancer specific (CSS), recurrence-free (RFS) and overall survival (OS) were performed.

Results: Total of 60 patients had complete radiological data available. Post-NAC PMV and BMI declines were statistically significant, 4.9% and 0.05%, respectively. NAC dose reduction/delay was a significant predictor of PMV loss (coefficient B 4.6; 95% CI 0.05–9.2; p = 0.047). The proportion of PMV decline during NAC was not a predictor of pPR, pCR, complications, readmission, CSS, RFS, or OS.

Conclusions: We observed an interval decline in PMV during the period of NAC administration and this decline was more than it could be appreciated with changes in BMI during the same period. PMV decline was associated with the need for dose reduction/dose delay during NAC. In our series, PMV changes occurring during NAC administration were not predictive of pathologic response to chemotherapy, postoperative complications or survival.

Spine stereotactic radiosurgery with concurrent tyrosine kinase inhibitors for metastatic renal cell carcinoma

OBJECT

Systemic control of metastatic renal cell carcinoma (mRCC) has substantially improved with the development of VEGF, mTOR, and checkpoint inhibitors. The current first-line standard of care is a VEGF tyrosine kinase inhibitor (TKI). In preclinical models, TKIs potentiate the response to radiotherapy. Such improved efficacy may prolong the time to salvage therapies, including whole-brain radiotherapy or second-line systemic therapy.

As the prevalence of mRCC has increased, the utilization of spine stereotactic radiosurgery (SRS) has also increased. However, clinical outcomes following concurrent treatment with SRS and TKIs remain largely undefined. The purpose of this investigation was to determine the safety and efficacy of TKIs when delivered concurrently with SRS. The authors hypothesized that first-line TKIs delivered concurrently with SRS significantly increase local control compared with SRS alone or TKIs alone, without increased toxicity.

METHODS

A retrospective cohort study of patients undergoing spine SRS for mRCC was conducted. Patients undergoing SRS were divided into 4 cohorts: those receiving concurrent first-line TKI therapy (A), systemic therapy–naïve patients (B), and patients who were undergoing SRS with (C) or without (D) concurrent TKI treatment after failure of first-line therapy. A negative control cohort (E) was also included, consisting of patients with spinal metastases managed with TKIs alone. The primary outcome was 12-month local failure, defined as any in-field radiographic progression. Multivariate competing risks regression was used to determine the independent effect of concurrent first-line TKI therapy upon local failure.

RESULTS

One hundred patients who underwent 151 spine SRS treatments (232 vertebral levels) were included. At the time of SRS, 46% were receiving concurrent TKI therapy. In each SRS cohort, the median prescription dose was 16 Gy in 1 fraction. Patients in Cohort A had the highest burden of epidural disease (96%, p < 0.01).

At 12 months, the cumulative incidence of local failure was 4% in Cohort A, compared with 19%–27% in Cohorts B–D and 57% in Cohort E (p < 0.01). Multivariate competing risks regression demonstrated that concurrent first-line TKI treatment (Cohort A) was independently associated with a local control benefit (HR 0.21, p = 0.04). In contrast, patients treated with TKIs alone (Cohort E) experienced an increased rate of local failure (HR 2.43, p = 0.03). No toxicities of Grade 3 or greater occurred following SRS with concurrent TKI treatment, and the incidence of post-SRS vertebral fracture (overall 21%) and pain flare (overall 17%) were similar across cohorts.

CONCLUSIONS

The prognosis for patients with mRCC has significantly improved with TKIs. The present investigation suggests a local control benefit with the addition of concurrent first-line TKI therapy to spine SRS. These results have implications in the oligometastatic setting and support a body of preclinical radiobiological research.

Systemic GM-CSF Recruits Effector T Cells into the Tumor Microenvironment in Localized Prostate Cancer

Granulocytic-macrophage colony-stimulating factor (GM-CSF) is used as an adjuvant in cancer vaccine trials and has the potential to enhance antitumor efficacy with immunotherapy; however, its immunologic effects are not fully understood. Here, we report results from a phase I study of neoadjuvant GM-CSF in patients with localized prostate cancer undergoing radical prostatectomy. Patients received subcutaneous injections of GM-CSF (250 μg/m²/day) daily for 2 weeks (cohort 1; n = 6), 3 weeks (cohort 2; n = 6), or 4 weeks (cohort 3; n = 6). Treatment was well tolerated with all grade 1 or 2 adverse events. Two patients had a decline in prostate-specific antigen (PSA) of more than 50%. GM-CSF treatment increased the numbers of circulating mature myeloid dendritic cells, proliferating conventional CD4 T cells, proliferating CD8 T cells, and to a lesser magnitude FoxP3⁺ regulatory CD4 T cells. Although GM-CSF treatment did not augment antigen-presenting cell localization to the prostate, treatment was associated with recruitment of CD8⁺ T cells to the tumor. These results suggest that systemic GM-CSF can modulate T-cell infiltration in the tumor microenvironment. Cancer Immunol Res; 4(11); 948-58. ©2016 AACR.

Safety and clinical activity of vascular endothelial growth factor receptor (VEGFR)-tyrosine kinase inhibitors after programmed cell death 1 inhibitor treatment in patients with metastatic clear cell renal cell carcinoma

BACKGROUND

Emerging agents blocking the programmed cell death 1 (PD-1) pathway show activity in metastatic clear cell renal cell carcinoma (mRCC). The aim of this study was to evaluate the efficacy and safety of vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR)-tyrosine kinase inhibitor (TKI) therapy after PD-1 inhibition.

PATIENTS AND METHODS

Patients with mRCC treated with anti-PD-1 antibody (aPD-1) monotherapy or in combination (with VEGFR-TKI or ipilimumab) that subsequently received VEGFR-TKI were retrospectively reviewed. The efficacy end points were objective response rate (ORR) and progression-free survival (PFS) stratified by the type of prior PD-1 regimen. Safety by the type and PD-1 exposure was also evaluated.

RESULTS

Seventy patients were included. Forty-nine patients received prior therapy with immune checkpoint inhibitors (CPIs) alone and 21 had combination therapy of aPD-1 and VEGFR-TKI. Overall, ORR to VEGFR-TKI after PD-1 inhibition was 28% (19/68) and the median PFS was 6.4 months (mo) (4.3-9.5). ORR to VEGFR-TKI after aPD-1 in combination with VEGFR-TKI was lower than that in patients treated with VEGFR-TKI after CPI alone (ORR 10% versus 36%, P = 0.039). In the multivariable analysis, patients treated with prior CPI alone were more likely to achieve an objective response than those treated with aPD-1 in combination with VEGFR-TKI (OR = 5.38; 95% CI 1.12-26.0, P = 0.03). There was a trend toward numerically longer median PFS in the VEGFR-TKI after the CPI alone group, 8.4 mo (3.2-12.4) compared with 5.5 mo (2.9-8.3) for those who had VEGFR-TKI after aPD-1 in combination with VEGFR-TKI (P = 0.15). The most common adverse events (AEs) were asthenia, hypertension, and diarrhea.

CONCLUSIONS

The efficacy and safety of VEGFR-TKIs after PD-1 inhibition were demonstrated in this retrospective study. The response rate was lower and the median progression-free survival was shorter in those patients who received prior PD-1 in combination with VEGFR-TKI. PD-1 exposure does not seem to significantly influence the safety of subsequent VEGFR-TKI treatment.

Change in Neutrophil-to-lymphocyte Ratio in Response to Targeted Therapy for Metastatic Renal Cell Carcinoma as a Prognosticator and Biomarker of Efficacy

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR), if elevated, is associated with worse outcomes in several malignancies.

OBJECTIVE

Investigation of NLR at baseline and during therapy for metastatic renal cell carcinoma.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of 1199 patients from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC cohort) and 4350 patients from 12 prospective randomized trials (validation cohort).

INTERVENTION

Targeted therapies for metastatic renal cell carcinoma.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

NLR was examined at baseline and 6 (± 2) wk later. A landmark analysis at 8 wk was conducted to explore the prognostic value of relative NLR change on overall survival (OS), progression-free survival (PFS), and objective response rate using Cox or logistic regression models, adjusted for variables in IMDC score and NLR values at baseline.

RESULTS AND LIMITATIONS

Higher NLR at baseline was associated with shorter OS and PFS (Hazard Ratios [HR] per 1 unit increase in log-transformed NLR = 1.69 [95% confidence interval {CI} = 1.46-1.95] and 1.30 [95% CI = 1.15-1.48], respectively). Compared with no change (decrease < 25% to increase < 25%, reference), increase NLR at Week 6 by 25-50% and > 75% was associated with poor OS (HR=1.55 [95% CI=1.10-2.18] and 2.31 [95% CI=1.64-3.25], respectively), poor PFS (HR=1.46 [95% CI=1.04-2.03], 1.76 [95% CI=1.23-2.52], respectively), and reduced objective response rate (odds ratios = 0.77 [95% CI=0.37-1.63] and 0.24 [95% CI=0.08-0.72], respectively). By contrast, a decrease of 25-50% was associated with improved outcomes. Findings were confirmed in the validation cohort. The study is limited by its retrospective design.

CONCLUSIONS

Compared with no change, early decline of NLR is associated with favorable outcomes, whereas an increase is associated with worse outcomes.

PATIENT SUMMARY

We found that the proportion of immune cells in the blood is of prognostic value, namely that a decrease of the proportion of neutrophils-to-lymphocytes is associated with more favorable outcomes while an increase had the opposite effect.

Axitinib for the treatment of metastatic renal cell carcinoma

Renal cell carcinoma is a cancer that results from a genetic inactivation of the VHL tumor suppressor gene leading to an upregulation of VEGF. Targeted therapies against VEGF receptors have piqued substantial interest among clinicians and researchers, and these drugs are now the standard of care in the treatment of advanced renal cell carcinoma. One of these VEGF receptor inhibitors, axitinib, has been shown to be a superior second-line therapy when compared with sorafenib. Although axitinib has clinical activity and a manageable safety profile in patients with treatment-naive metastatic renal cell carcinoma, utility in the front-line setting is area of ongoing investigation. Another area of ongoing research is dose titration of axitinib to achieve the maximum clinical benefit. Interestingly, the axitinib-related side effect of hypertension has shown to be associated with more favorable clinical outcomes. This article describes the development of axitinib and discusses the current indications for clinical use in the management of metastatic renal cell carcinoma.

A Molecular Model for Predicting Overall Survival in Patients with Metastatic Clear Cell Renal Carcinoma: Results from CALGB 90206 (Alliance)

BACKGROUND

Prognosis associated with metastatic renal cell carcinoma (mRCC) can vary widely.

METHODS

This study used pretreatment nephrectomy specimens from a randomized phase III trial. Expression levels of candidate genes were determined from archival tumors using the OpenArray® platform for TaqMan® RT-qPCR. The dataset was randomly divided at 2:1 ratio into training (n = 221) and testing (n = 103) sets to develop a multigene prognostic signature.

FINDINGS

Gene expressions were measured in 324 patients. In the training set, multiple models testing 424 candidate genes identified a prognostic signature containing 8 genes plus MSKCC clinical risk factors. In the testing set, the time dependent (td) AUC for a prognostic model containing the 8 genes with and without MSKCC risk factors were 0.72 and 0.69, respectively. The tdAUC for the clinical risk factors alone was 0.61. Additional primary mRCCs from patients with mRCC (n = 12) were sampled in multiple sites and standard deviations of gene expressions within a tumor were used as a measure of heterogeneity. All 8 genes in the final prognostic model met our criteria for minimal heterogeneity.

CONCLUSIONS

A molecular prognostic signature based on 8 genes was developed and is ready for external validation in this patient population and other related settings such as nonmetastatic RCC.

Algorithms in the First-Line Treatment of Metastatic Clear Cell Renal Cell Carcinoma--Analysis Using Diagnostic Nodes

BACKGROUND

With the advent of targeted therapies, many treatment options in the first-line setting of metastatic clear cell renal cell carcinoma (mccRCC) have emerged. Guidelines and randomized trial reports usually do not elucidate the decision criteria for the different treatment options. In order to extract the decision criteria for the optimal therapy for patients, we performed an analysis of treatment algorithms from experts in the field.

MATERIALS AND METHODS

Treatment algorithms for the treatment of mccRCC from experts of 11 institutions were obtained, and decision trees were deduced. Treatment options were identified and a list of unified decision criteria determined. The final decision trees were analyzed with a methodology based on diagnostic nodes, which allows for an automated cross-comparison of decision trees. The most common treatment recommendations were determined, and areas of discordance were identified.

RESULTS

The analysis revealed heterogeneity in most clinical scenarios. The recommendations selected for first-line treatment of mccRCC included sunitinib, pazopanib, temsirolimus, interferon-α combined with bevacizumab, high-dose interleukin-2, sorafenib, axitinib, everolimus, and best supportive care. The criteria relevant for treatment decisions were performance status, Memorial Sloan Kettering Cancer Center risk group, only or mainly lung metastases, cardiac insufficiency, hepatic insufficiency, age, and "zugzwang" (composite of multiple, related criteria).

CONCLUSION

In the present study, we used diagnostic nodes to compare treatment algorithms in the first-line treatment of mccRCC. The results illustrate the heterogeneity of the decision criteria and treatment strategies for mccRCC and how available data are interpreted and implemented differently among experts.

IMPLICATIONS FOR PRACTICE

The data provided in the present report should not be considered to serve as treatment recommendations for the management of treatment-naïve patients with multiple metastases from metastatic clear cell renal cell carcinoma outside a clinical trial; however, the data highlight the different treatment options and the criteria used to select them. The diversity in decision making and how results from phase III trials can be interpreted and implemented differently in daily practice are demonstrated.

A 16-gene assay to predict recurrence after surgery in localised renal cell carcinoma: development and validation studies

BACKGROUND

The likelihood of tumour recurrence after nephrectomy in localised clear cell renal cell carcinoma is well characterised by clinical and pathological parameters. However, these assessments can be improved and personalised by the addition of molecular characteristics of each patient's tumour. We aimed to develop and validate a prognostic multigene signature to improve prediction of recurrence risk in clear cell renal cell carcinoma.

METHODS

In the development stage, we investigated the association between expression of 732 genes, measured by reverse-transcription PCR, and clinical outcome in 942 patients with stage I-III clear cell renal cell carcinoma who had undergone a nephrectomy at the Cleveland Clinic (OH, USA). 516 genes were associated with recurrence-free interval. 11 of these genes were selected by further statistical analyses, and were combined with five reference genes (ie, 16 genes in total), from which a recurrence score algorithm was developed. The recurrence score was then validated in an independent cohort of 626 patients from France with stage I-III clear cell renal cell carcinoma who had also undergone nephrectomy. The association between the recurrence score and the risk of recurrence and cancer-specific survival in the first 5 years after surgery was assessed using Cox proportional hazard regression, stratified by tumour stage (stage I vs stage II vs III).

FINDINGS

In our primary univariate analysis, the continuous recurrence score (median 37, IQR 31-45) was significantly associated with recurrence-free interval (hazard ratio 3·91 [95% CI 2·63-5·79] for a 25-unit increase in score, p<0·0001). In multivariable analyses, the recurrence score was significantly associated with the risk of tumour recurrence (hazard ratio per 25-unit increase in the score 3·37 [95% CI 2·23-5·08], p<0·0001) after stratification by stage and adjustment for tumour size, grade, or Leibovich score. The recurrence score was able to identify a clinically significant number of both high-risk stage I and low-risk stage II-III patients. A heterogeneity study on separate samples showed little to no intratumoural variability among the 16 genes.

INTERPRETATION

Our findings validate the recurrence score as a predictor of clinical outcome in patients with stage I-III clear cell renal cell carcinoma, providing a more accurate and individualised risk assessment beyond existing clinical and pathological parameters.

FUNDING

Genomic Health Inc and Pfizer Inc.

A genomic algorithm for the molecular classification of common renal cortical neoplasms: development and validation

PURPOSE

Accurate discrimination of benign oncocytoma and malignant renal cell carcinoma is useful for planning appropriate treatment strategies for patients with renal masses. Classification of renal neoplasms solely based on histopathology can be challenging, especially the distinction between chromophobe renal cell carcinoma and oncocytoma. In this study we develop and validate an algorithm based on genomic alterations for the classification of common renal neoplasms.

MATERIALS AND METHODS

Using TCGA renal cell carcinoma copy number profiles and the published literature, a classification algorithm was developed and scoring criteria were established for the presence of each genomic marker. As validation, 191 surgically resected formalin fixed paraffin embedded renal neoplasms were blindly submitted to targeted array comparative genomic hybridization and classified according to the algorithm. CCND1 rearrangement was assessed by fluorescence in situ hybridization.

RESULTS

The optimal classification algorithm comprised 15 genomic markers, and involved loss of VHL, 3p21 and 8p, and chromosomes 1, 2, 6, 10 and 17, and gain of 5qter, 16p, 17q and 20q, and chromosomes 3, 7 and 12. On histological rereview (leading to the exclusion of 3 specimens) and using histology as the gold standard, 58 of 62 (93%) clear cell, 51 of 56 (91%) papillary and 33 of 34 (97%) chromophobe renal cell carcinomas were classified correctly. Of the 36 oncocytoma specimens 33 were classified as oncocytoma (17 by array comparative genomic hybridization and 10 by array comparative genomic hybridization plus fluorescence in situ hybridization) or benign (6). Overall 93% diagnostic sensitivity and 97% specificity were achieved.

CONCLUSIONS

In a clinical diagnostic setting the implementation of genome based molecular classification could serve as an ancillary assay to assist in the histological classification of common renal neoplasms.