The impact of FGFR1 and FRS2α expression on sorafenib treatment in metastatic renal cell carcinoma

Background

Angiogenesis plays a role in tumor growth and is partly mediated by factors in both the fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) pathways. Durable clinical responses with VEGF tyrosine kinase inhibitors (TKIs) may be limited by intrinsic tumor resistance. We hypothesized that FGF signaling may impact clinical responses to sorafenib.

Methods

Nephrectomy material was available from 40 patients with metastatic renal cell carcinoma (RCC) enrolled in a phase II clinical trial of sorafenib ± interferon (ClinicalTrials.gov Identifier NCT00126594). Fibroblast growth factor receptor 1 (FGFR1) and fibroblast growth factor receptor substrate 2 alpha (FRS2α) expression was assessed by in situ hybridization and immunofluorescence, respectively. The relationship between fibroblast growth factor pathway marker levels and progression-free survival (PFS) was analyzed using Kaplan-Meier and Cox proportional hazards regression methods.

Results

Univariate analysis indicated that more intense FGFR1 staining was associated with shorter PFS (log-rank P = 0.0452), but FRS2α staining was not significantly associated with PFS (log-rank P = 0.2610). Multivariate Cox proportional hazards regression models were constructed for FGFR1 and FRS2α individually, adjusting for baseline Eastern Cooperative Oncology Group performance status, treatment arm and anemia status. When adjusted for each of these variables, the highest intensity level of FGFR1 (level 3 or 4) had increased progression risk relative to the lowest intensity level of FGFR1 (level 1) (P = 0.0115). The highest intensity level of FRS2α (level 3 or 4) had increased progression risk relative to the lowest intensity level of FRS2α (level 1) (P = 0.0126).

Conclusions

Increased expression of FGFR1 and FRS2α was associated with decreased PFS among patients with metastatic RCC treated with sorafenib. The results suggest that FGF pathway activation may impact intrinsic resistance to VEGF receptor inhibition.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1302-1) contains supplementary material, which is available to authorized users.

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney: a detailed study of radiological, pathological and clinical outcomes

OBJECTIVE

To characterise the clinical, radiological and histological features of mucinous tubular and spindle cell carcinoma (MTSCC), as well as oncological outcomes.

PATIENTS AND METHODS

This is a single institution retrospective analysis of all patients with MTSCC from 2002 to 2011. Patients were excluded if MTSCC could not be confirmed on pathology re-review (four patients). Clinical characteristics, pathology, imaging, and outcomes were reviewed for the 19 included patients.

RESULTS

The median (range) age at diagnosis was 59 (17-71) years with a female predominance (78.9%). On contrast-enhanced computed tomography, MTSCC enhanced less than the cortex during the corticomedullary phase. The mean (range) tumour attenuation was 36 (24-48), 67 (41-133), 89 (49-152), and 76 (52-106) Hounsfield units in the pre-contrast, corticomedullary, nephrographic and excretory phases, respectively. In all, 16 patients were treated with partial (five patients) or radical nephrectomy (11) for pT1 (62.5%), pT2 (31.3%), and pT3a disease (6.3%). One patient underwent active surveillance. Of three patients (13.0%) managed with energy ablation, there was one recurrence that was treated with salvage surgery. One patient (5.3%) had metastatic disease at diagnosis and died from disease 64.7 months later. A patient with a pT2bN0M0 MTSCC with sarcomatoid dedifferentiation developed bone metastases 9.5 months after diagnosis and was alive at 19.0 months. The remainder were free of recurrence or progression.

CONCLUSION

MTSCC is a rare renal cell carcinoma (RCC) variant. In this largest series to date, MTSCC presented at a broad range of ages and displayed a female predilection. Imaging and pathological features of MTSCC display some overlap with papillary RCC. MTSCC is associated with excellent outcomes overall, but is not universally indolent.

Outcomes and prognosticators in patients with pathologic T4 renal cell carcinoma

514

Background: The 2010 American Joint Committee on Cancer (AJCC) TNM staging system defines pathological T4 renal cell carcinoma (RCC) as extension of tumor beyond Gerota’s fascia and/or invading contiguously into the adrenal gland. This subset of patients with the highest stage and locally advanced disease demonstrate poor outcomes with an estimated 5 year-survival rate of 20-30%. For this high-risk population, patient selection is imperative for proper patient counseling and to identify patients who would benefit from surgical intervention. Our objective was to study patient outcomes and determine prognostic variables predicting survival in pT4 RCC. Methods: From July 1992 to January 2012, we identified 64 patients at our institution who underwent radical nephrectomy and were found to have pT4 disease. The clinical and pathological variables were studied using univariate analysis to identify prognostic variables predicting survival using the Cox proportional hazards model. Survival plots were estimated using Kaplan-Meier method and survival analysis was performed using log-rank test. Results: Median patient age was 56 years (35-82), and 46 (68.7%) were male. Fifty-two (83%) patients had ECOG Performance Status 0 or 1. At diagnosis, 20 (32%) patients were M0 and 42 (68%) were M1. Median tumor size was 13 cm (5.5-25). Forty-nine (76%) patients had clear cell RCC and 26 (40%) had sarcomatoid features. Forty-seven (73.4%) patients had Fuhrman grade 3 or 4. Twenty-eight (44%) patients were pN0, 16 (25%) were pN1, and 20 (31%) were pNx. On multivariate analysis, the significant predictors of survival (p < 0.05) were M stage at time of nephrectomy, pN stage, performing LN dissection, Fuhrman grade, and presence of sarcomatoid features. Conclusions: Survival in patients with pT4 remains poor. Predictors of survival in pT4 RCC patients include M stage, N stage, LN dissection, Fuhrman grade, and sarcomatoid features. Preoperative identification of patients with pT4 needs refinement, and could help improve patient management and selection for inclusion in neoadjuvant trials.

Association of resistance to antiangiogenic therapy with an immunosuppressive tumor microenvironment in metastatic renal cell carcinoma

419

Background: Renal cell carcinoma (RCC) is an immunogenic and proangiogenic cancer, and anti-angiogenic therapy is the current mainstay of treatment. RCC patients develop innate or adaptive resistance to anti-angiogenic therapy. There is a need to identify biomarkers which predict therapeutic resistance and guide combination therapy. Methods: Tissue microarrays with triplicate cores for each case were generated from 33 unaffected kidneys, 41 untreated primary RCC, and 42 bevacizumab and 39 sunitinib pretreated primary RCC from patients with metastatic RCC. Immunohistochemistry was used to visualize immune cell infiltration. Staining quantitation was performed using a Vectra multispectral system. Statistical analysis was performed using unpaired Student´s t-test. Results: We assessed the interaction between anti-angiogenic therapy and tumor immune microenvironment, and determined their impact on clinical outcome. Here we found that anti-angiogenic therapy treated RCC primary tumors demonstrated increased infiltration of CD4+ and CD8+ T lymphocytes, which was inversely related to patient survival. Furthermore, anti-angiogenic therapy treated specimens showed higher infiltration of CD4+FOXP3+regulatory T cells (Tregs) and enhanced expression of checkpoint ligand programed death-ligand 1 (PD-L1). Both immunosuppressive features were correlated with T lymphocyte infiltration and were negatively related to patient overall survival (OS) and/or progression free survival (PFS). Treatment of RCC cell lines and RCC xenografts in immunodeficient mice with sunitinib also increased tumor PD-L1 expression. Conclusions: This study indicates that anti-angiogenic treatment may both positively and negatively regulate the tumor immune microenvironment. These findings generate hypotheses on resistance mechanisms to antiangiogenic therapy, and will guide the development of combination therapy with PD-1/PD-L1 blocking agents.

Surgical management for local retroperitoneal recurrence after radical nephrectomy in the targeted therapy era

431

Background: Isolated local retroperitoneal recurrence (RPR) after radical nephrectomy (RN) for renal cell carcinoma (RCC) poses a therapeutic challenge. We examined the role of aggressive surgical resection of localized RPR in the modern era of targeted therapy for metastatic RCC. Methods: We retrospectively reviewed clinico-pathological data of patients from our RCC database from 2004-2014. We identified 67 patients with localized RPR after radical nephrectomy (RN) who underwent surgical resection. We assessed patient demographics, clinical and pathological features, location of RPR, perioperative complications and outcomes, recurrence free, cancer-specific and overall survival. Results: Median follow up after RPR resection was 33 months (range 3-120). Median recurrence free survival after RPR was 20 months (range 1-120). One, 3 and 5-year cancer specific survival was 95% 77% and 50%, respectively. Neoadjuvant and salvage targeted therapy were administered in 29 (43.3%) and 28 (41.8%) patients, respectively. Multivariate analysis identified that pathological tumor stage and nodal stage at nephrectomy, maximum diameter of RPR mass and abnormal lactate dehydrogenase levels were associated with an increased risk of cancer specific death. Patients with 0, 1, and greater than 1 adverse risk factors demonstrated cancer specific survival of 100%, 74%, 50% at 3 years and 100%, 57%, 19% at 5 years. Conclusions: This study is the largest series of patients to undergo RPR resection in the targeted therapy era. We found that clinic-pathological factors at the time of nephrectomy as well as RPR resection are important prognosticators. Aggressive surgical resection offers potential cure in a substantial number of patients with RPR.

Percentage of sarcomatoid component as a prognostic indicator for survival in sarcomatoid renal cell carcinoma

499

Background: Renal cell carcinoma with sarcomatoid component (sRCC) is characterized by the microscopic spectrum of spindle cells within a background of RCC. The presence of sarcomatoid elements is associated with higher stage of presentation and decreased patient survival. The objective of this study is to examine the clinicopathological characteristics associated with overall survival (OS), specifically examining the percentage of sarcomatoid component (PSC) to stratify risk. Methods: We retrospectively reviewed data for all radical nephrectomy patients with pathologically confirmed sarcomatoid component from 1987−2011. All slides were re−reviewed by a GU pathologist to ascertain PSC. Patient characteristics were tabulated overall and by disease status (metastatic vs. localized). Cutpoints in the percent sarcomatoid providing a meaningful difference in OS were identified by recursive partitioning analysis (RPA) as univariate and combined with patient characteristics. Factors selected included age, gender, race, clinical stage, tumor histology, and treatment. The Kaplan−Meier method and two−sided log−rank test was used to assess differences in OS. Results: Among 186 patients with sRCC, 64 (34%) had localized and 122 (66%) metastatic disease. Patients were primarily white (76%) males (63%) with clear cell histology (73%), and did not receive neoadjuvant or adjuvant therapy (87%). The median follow−up time was 12.1 months (range, 0.1 to 242.2 months). The median OS was 12.6 months (95% confidence interval (CI) 10.7−14.9 months). Two subgroups were identified with a cut−point of 12.5% for PSC after univariate RPA. Patients with PSC ≥ %12.5 were at higher risk of death compared to patients with <%12.5 (45% vs. 61% 1 year OS; p value=0.04). Mutlivariate RPA revealed clinical stage and percent sarcomatoid were significantly associated with OS. Patients with localized disease were most likely to be alive at 1 year (74%). Among patients with metastatic disease with PSC<%42.5 had 1−year OS of 44% vs. 27% for patients with ≥%42.5 cutoff (p<0.001). Conclusions: The PSC appears to be a prognostic factor in the OS of patients with RCC, with larger percentage of involvement portending a worse survival.

Proteomic stratification of clear cell renal cell carcinoma utilizing The Cancer Genome Atlas (TCGA) with external validation

406

Background: Proteomics represents the ultimate convergence of DNA and expression alterations. We therefore sought to leverage TCGA reverse phase protein array (RPPA) data with an independent proteomic platform to identify druggable targets and pathways associated with prognosis in clear cell renal cell carcinoma (ccRCC). Methods: Unsupervised hierarchical consensus clustering was performed and differentially expressed proteins were identified for pathway analysis. Associations with clinicogenomic factors were assessed and Cox proportional hazards models were performed for disease-specific survival (DSS). Results: RPPA clustering of 324 patients from the ccRCC TCGA revealed 5 robust clusters characterized by alterations in specific pathways and divergent prognoses. Cluster 1 was characterized by poor DSS, decreased expression of receptor tyrosine kinases (RTK) and upregulation of the mTOR pathway. It was also associated with mTOR pathway genomic alterations, sarcomatoid histology and the ccb prognostic mRNA signature (all p<0.001). Cluster 2 was characterized by increased expression of RTKs and interestingly, had upregulation of the mTOR pathway with excellent DSS. After accounting for stage and grade, cluster designation remained independently associated with DSS (HR 0.23 for cluster 2, 95% CI 0.08-0.68; p=0.008). External validation was performed on a separate cohort of 189 patients with a different quantitative proteomics platform. A panel of phosphoproteins (pHER1, pHER2, pHER3, pSHC, pMEK, pAKT), highly discriminant between the most divergent RPPA clusters (1 and 2) was evaluated. Those at the highest quartile of activation in > 3 proteins were associated with improved DSS (HR 0.19, 95% CI 0.05-0.082; p=0.03). Patients with mTOR pathway activation segregated to those with coincident RTK activation (n=83) and those without (n=13). Conclusions: We have identified and validated proteomic signatures which cluster ccRCC patients into 5 prognostic groups. Furthermore, two distinct mTOR-activated clusters—one with high RTK activity and one with increased mTOR pathway genomic alterations were revealed, which may have prognostic and therapeutic implications.

Clinically nonmetastatic renal cell carcinoma with sarcomatoid dedifferentiation: Natural history and outcomes after surgical resection with curative intent

PURPOSE

Renal cell carcinoma with sarcomatoid dedifferentiation (sRCC) is an aggressive malignancy associated with a poor prognosis. Although existing literature focuses on patients presenting with metastatic disease, characteristics and outcomes for patients with localized disease are not well described. We aimed to evaluate postnephrectomy characteristics, outcomes, and predictors of survival in patients with sRCC who presented with clinically localized disease.

PATIENTS AND METHODS

An institutional review board-approved review from 1986 to 2011 identified 77 patients who presented with clinically localized disease, underwent nephrectomy, and had sRCC in their primary kidney tumor. Clinical and pathologic variables were captured for each patient. Overall survival (OS) and recurrence-free survival (RFS) were calculated for all patients and those who had no evidence of disease (NED) following nephrectomy, respectively. Comparisons were made with categorical groupings in proportional hazards regression models for univariable and multivariable analyses.

RESULTS

OS for the entire cohort (n = 77) at 2 years was 50%. A total of 56 (77%) patients of the 73 who has NED following nephrectomy experienced a recurrence, with a median time to recurrence of 26.2 months. On multivariable analysis, tumor stage, pathologically positive lymph nodes, and year of nephrectomy were significant predictors of both OS and recurrence-free survival. Limitations include the retrospective nature of this study and relatively small sample size.

CONCLUSIONS

Long-term survival for patients with sRCC, even in clinically localized disease, is poor. Aggressive surveillance of those who have NED following nephrectomy is essential, and further prospective studies evaluating the benefit of adjuvant systemic therapies in this cohort are warranted.

Expression of Ror2 mediates invasive phenotypes in renal cell carcinoma

Ror2 is a Wnt ligand receptor that is overexpressed in a variety of tumors including clear cell renal cell carcinoma (ccRCC). Here we demonstrate that expression of wild type Ror2 results in increased tumorigenic properties in in vitro cell culture and in vivo xenograft models. In addition, Ror2 expression produced positive changes in both cell migration and invasion, which were dependent on matrix metalloprotease 2 (MMP2) activity. Mutations in key regions of the kinase domain of Ror2 resulted in the abrogation of increased tumor growth, cell migration, and cell invasion observed with expression of wild-type Ror2. Finally, we examined Ror2 expression as a prognostic biomarker for ccRCC utilizing the TCGA ccRCC dataset. High expression of Ror2 showed a significant correlation with higher clinical stage, nuclear grade, and tumor stage. Furthermore, high expression of Ror2 in ccRCC patients correlated with significant lower overall survival, cancer specific survival, and recurrence free survival. Together, these findings suggest that Ror2 plays a central role in influencing the ccRCC phenotype, and can be considered as a negative prognostic biomarker and potential therapeutic target in this cancer.

Genomic investigation of etiologic heterogeneity: methodologic challenges

Background

The etiologic heterogeneity of cancer has traditionally been investigated by comparing risk factor frequencies within candidate sub-types, defined for example by histology or by distinct tumor markers of interest. Increasingly tumors are being profiled for molecular features much more extensively. This greatly expands the opportunities for defining distinct sub-types. In this article we describe an exploratory analysis of the etiologic heterogeneity of clear cell kidney cancer. Data are available on the primary known risk factors for kidney cancer, while the tumors are characterized on a genome-wide basis using expression, methylation, copy number and mutational profiles.

Methods

We use a novel clustering strategy to identify sub-types. This is accomplished independently for the expression, methylation and copy number profiles. The goals are to identify tumor sub-types that are etiologically distinct, to identify the risk factors that define specific sub-types, and to endeavor to characterize the key genes that appear to represent the principal features of the distinct sub-types.

Results

The analysis reveals strong evidence that gender represents an important factor that distinguishes disease sub-types. The sub-types defined using expression data and methylation data demonstrate considerable congruence and are also clearly correlated with mutations in important cancer genes. These sub-types are also strongly correlated with survival. The complexity of the data presents many analytical challenges including, prominently, the risk of false discovery.

Conclusions

Genomic profiling of tumors offers the opportunity to identify etiologically distinct sub-types, paving the way for a more refined understanding of cancer etiology.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2288-14-138) contains supplementary material, which is available to authorized users.

Preoperative predictors of pathological lymph node metastasis in patients with renal cell carcinoma undergoing retroperitoneal lymph node dissection

PURPOSE

Patients with locally advanced renal cell carcinoma represent a subset that may benefit from retroperitoneal lymph node dissection. We identified preoperative clinical predictors of positive lymph nodes in patients with renal cell carcinoma without distant metastasis who underwent retroperitoneal lymph node dissection.

MATERIALS AND METHODS

We retrospectively analyzed data on a consecutive cohort of 1,270 patients with cTany Nany M0 renal cell carcinoma who were treated at a single institution from 1993 to 2012. Multivariate analysis was performed to determine preoperative predictors of pathologically positive lymph nodes in patients who underwent retroperitoneal lymph node dissection. A nomogram was developed to predict the probability of lymph node metastasis. Overall, cancer specific and recurrence-free survival was estimated using the Kaplan-Meier Method.

RESULTS

We identified 1,270 patients with renal cell carcinoma without distant metastasis who had (564) or did not have (706) retroperitoneal lymph node dissection performed. Of the 564 patients 131 (23%) and 433 (77%) had pN1 and pN0 disease, and 60 (37%) and 29 (7.2%) had cN1pN0 and cN0pN1 disease, respectively. ECOG PS, cN stage, local symptoms and lactate dehydrogenase were associated with nodal metastasis on multivariable analysis. A nomogram was developed with a C-index of 0.89 that demonstrated excellent calibration. Differences in overall, cancer specific and recurrence-free survival among pNx, pN0 and pN1 cases were statistically significant (p <0.001).

CONCLUSIONS

Local symptoms, ECOG PS, cN stage and lactate dehydrogenase were independent predictors of lymph node metastasis in patients who underwent retroperitoneal lymph node dissection. Our predictive nomogram using these factors showed excellent discrimination and calibration.

The somatic genomic landscape of chromophobe renal cell carcinoma

We describe the landscape of somatic genomic alterations of 66 chromophobe renal cell carcinomas (ChRCCs) on the basis of multidimensional and comprehensive characterization, including mtDNA and whole-genome sequencing. The result is consistent that ChRCC originates from the distal nephron compared with other kidney cancers with more proximal origins. Combined mtDNA and gene expression analysis implicates changes in mitochondrial function as a component of the disease biology, while suggesting alternative roles for mtDNA mutations in cancers relying on oxidative phosphorylation. Genomic rearrangements lead to recurrent structural breakpoints within TERT promoter region, which correlates with highly elevated TERT expression and manifestation of kataegis, representing a mechanism of TERT upregulation in cancer distinct from previously observed amplifications and point mutations.

Clear cell papillary renal cell carcinoma in patients with von Hippel-Lindau syndrome--clinicopathological features and comparative genomic analysis of 3 cases

Clear cell papillary renal cell carcinoma (CCPRCC) is a renal neoplasm that has recently received widespread recognition in the literature. There have been several reports of this tumor arising in a sporadic setting and in patients with end-stage renal disease; however, there is limited information available about the clinical, pathologic, and genetic characteristics of this tumor in the setting of von Hippel-Lindau (VHL) disease. We herein report a series of 3 patients who developed CCPRCC in this unique clinical setting. The histology and immunohistochemical profile for all 3 cases was similar to that which has been previously reported for CCPRCC. All tumors were diffusely and strongly positive for cytokeratin 7, negative for α-methyl-CoA-racemase, and showed at least focal staining for CD10. Comparative genomic analysis was performed on tumors from all 3 patients. One tumor demonstrated monosomy 3, and the other 2 tumors showed normal chromosomal content. All 3 patients were alive without evidence of disease progression 5, 3, and 3 years after surgery. CCPRCC represents a distinct tumor type that may occur in the setting of VHL disease and should be considered in the differential diagnosis of extensively cystic renal tumors arising in this clinical setting. Molecular analysis in our series of cases suggests that CCPRCC does indeed represent a unique histologic subtype and must be distinguished from clear cell renal cell carcinoma due to different biological potentials. Ancillary studies for accurate classification are recommended due to significant morphologic overlap with clear cell renal cell carcinoma.

Primary intra-renal desmoplastic small round cell tumor: expanding the histologic spectrum, with special emphasis on the differential diagnostic considerations

Intra-abdominal desmoplastic small round cell tumor (DSRCT) is a rare, aggressive tumor affecting adolescent and young males. DSRCT presenting as a primary renal mass in the absence of visceral or serosal involvement is extremely rare. Herein, we present the pathologic and molecular findings in the case of a young man who presented with a large renal mass without any visceral or serosal involvement. Noticeably, the tumor lacked prominent desmoplastic stroma and only focally expressed cytokeratin, both of which are considered characteristic histologic features for this tumor. Fluorescence in situ hybridization studies using an EWSR1 break-apart probe confirmed the presence of a rearrangement involving the EWSR1 locus and RT-PCR demonstrated the presence of an EWSR1-WT1 fusion transcript associated with the t(11;22) rearrangement, which supported a diagnosis of DSRCT. We also discuss the differential diagnostic considerations faced by the pathologist in the workup of small round cell neoplasms of the kidney.

Collision tumor of the kidney composed of clear cell carcinoma and collecting duct carcinoma: report of a case with unusual morphology and clinical follow-up

We report the case of a 67-year-old female who presented with a large renal mass. Gross examination of the nephrectomy specimen demonstrated a 6-cm renal mass that invaded into the renal sinus and perinephric fat. Histologic examination revealed two distinct tumor types. The first type was a conventional (clear cell) renal cell carcinoma that was of low nuclear grade and comprised the minority of the overall tumor. The second type was a high-grade collecting duct carcinoma with glandular/tubular differentiation and composed the majority of the tumor. Immunohistochemical studies demonstrated distinctive patterns of the two tumor types, thus confirming two distinct lineages. Five months postoperatively, the patient developed metastasis to the lungs and right hilar lymph node region. A fine needle aspiration of a lung nodule demonstrated a metastatic, poorly differentiated carcinoma, similar to the collecting duct carcinoma component in the kidney. Collision tumors of the kidney are rare with fewer than 10 cases reported in the literature. Our report further expands the spectrum of this rare phenomenon.

ClearCode34: A prognostic risk predictor for localized clear cell renal cell carcinoma

BACKGROUND

Gene expression signatures have proven to be useful tools in many cancers to identify distinct subtypes of disease based on molecular features that drive pathogenesis, and to aid in predicting clinical outcomes. However, there are no current signatures for kidney cancer that are applicable in a clinical setting.

OBJECTIVE

To generate a signature biomarker for the clear cell renal cell carcinoma (ccRCC) good risk (ccA) and poor risk (ccB) subtype classification that could be readily applied to clinical samples to develop an integrated model for biologically defined risk stratification.

DESIGN, SETTING, AND PARTICIPANTS

A set of 72 ccRCC sample standards was used to develop a 34-gene classifier (ClearCode34) for assigning ccRCC tumors to subtypes. The classifier was applied to RNA-sequencing data from 380 nonmetastatic ccRCC samples from the Cancer Genome Atlas (TCGA), and to 157 formalin-fixed clinical samples collected at the University of North Carolina.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Kaplan-Meier analyses were performed on the individual cohorts to calculate recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). Training and test sets were randomly selected from the combined cohorts to assemble a risk prediction model for disease recurrence.

RESULTS AND LIMITATIONS

The subtypes were significantly associated with RFS (p<0.01), CSS (p<0.01), and OS (p<0.01). Hazard ratios for subtype classification were similar to those of stage and grade in association with recurrence risk, and remained significant in multivariate analyses. An integrated molecular/clinical model for RFS to assign patients to risk groups was able to accurately predict CSS above established, clinical risk-prediction algorithms.

CONCLUSIONS

The ClearCode34-based model provides prognostic stratification that improves upon established algorithms to assess risk for recurrence and death for nonmetastatic ccRCC patients.

PATIENT SUMMARY

We developed a 34-gene subtype predictor to classify clear cell renal cell carcinoma tumors according to ccA or ccB subtypes and built a subtype-inclusive model to analyze patient survival outcomes.