Comparisons of outcome and prognostic features among histologic subtypes of renal cell carcinoma

Percentage of high-grade carcinoma as a prognostic indicator in patients with renal cell carcinoma

BACKGROUND

The prognostic value of Fuhrman nuclear grade for patients with renal cell carcinoma has been well-characterized. However, to the authors' knowledge, the prognostic significance of the amount of high-grade renal cell carcinoma has not been previously analyzed.

METHODS

The authors identified 898 consecutive renal cell carcinoma cases treated with nephrectomy between 1989 and 2003. Histopathologic features that were captured based on re-review of all slides included histologic type, pathologic stage, conventional Fuhrman grade, and percentage of Fuhrman grade 3 and 4 carcinoma, as ascertained by visual inspection of histologic slides. The clinical endpoints were metastasis-free survival, cancer-specific survival, and overall survival.

RESULTS

Kaplan-Meier analysis demonstrated that both conventional Fuhrman grading and the percentage of Fuhrman grade 3 and 4 carcinoma were highly correlated with all 3 measures of patient survival (P < .0001). The creation of 3 categories of the percentage of Fuhrman grade 3 and 4 carcinoma (0%, 1-50%, and 51-100%) generated distinctly separate survival curves. On Cox proportional hazards multivariate analysis, TNM stage, tumor size, and the percentage of Fuhrman grade 3 and 4 carcinoma were all found to be significantly associated with all 3 types of patient survival (all P values <.05).

CONCLUSIONS

The determination of the percentage of renal cell carcinoma that is 0%, 1% to 50%, or 51% to 100% high Fuhrman grade 3 and 4 is a simple and powerful measurement of patient outcome after surgery that provides additional prognostic information beyond stage, tumor size, and conventional Fuhrman grade. This prognostic information could be useful in the stratification of patients into prognostic groups for the development of more individualized follow-upschedules and for enrollment into clinical trials.

Comparison of type I and II papillary renal cell carcinoma (RCC) and clear cell RCC

OBJECTIVE

To compare the pathological features of clear cell renal cell carcinoma (ccRCC) with papillary RCC (pRCC) and further differentiate type I and II pRCC as independent prognosticators for survival.

PATIENTS AND METHODS

From September 1994 to February 2007 557 RCCs were treated and reviewed. All patients underwent radical nephrectomy or nephron-sparing surgery. We reviewed patient data and correlated RCC subtypes to tumour size, pathological stage, nuclear grade, and 5-year cancer-specific survival (CSS). pRCC was re-evaluated in to type I and II. The 2002 Tumour-Node-Metastasis and Fuhrman classifications were used.

RESULTS

In all, 391 (70%) patients had ccRCC, 96 (17%) had pRCC, 34 (6%) had chromophobe RCC, seven (1%) had ductus Bellini RCC and 29 (5%) had unclassified RCC. Upon re-evaluation 34 patients had type I pRCC and 62 had type II. The pRCCs were significantly smaller than the ccRCCs, at a mean (sd) of 4.5 (2.5) cm vs 5 (2.9) cm (P = 0.013), and multifocal (25% vs 12%, P = 0.001). Whereas patients with ccRCC had significantly more primary metastases (12% vs 3%, P = 0.014). The mean (sd) follow-up was 42.3 (41.4) months. The 5-year CSS for M0 patients was 84% for ccRCC and 90% for pRCC (P = 0.573). At multivariate analyses predictors for 5-year CSS were only tumour size (hazard ratio, HR 2.6, P < 0.001), pathological stage (HR 3.9, P < 0.001) and nuclear grade (HR 2.7, P < 0.001). The type I and II pRCCs had significantly different lymphovascular invasion (LVI) and 5-year CSS rates (94% vs 74%, P = 0.03).

CONCLUSIONS

The ccRCCs were significantly larger at diagnosis than the pRCCs. The histological subtype (pRCC vs ccRCC) had no impact on the 5-year CSS in multivariate analyses. The type I and II pRCCs had similar histopathological features except for a significant difference in LVI. However, the 5-year CSS was significantly different in type I and II pRCC.

Targeted therapies in the management of renal cell carcinoma: role of bevacizumab

Bevacizumab (10 mg/kg every 2 weeks), in combination with interferon alpha-2a (IFN), is an effective option for first-line therapy for advanced and/or metastatic renal cell carcinoma (RCC). Two phase III trials clearly show significant improvements in progression-free survival and response rate in patients with treatment-naïve metastatic RCC receiving bevacizumab combined with IFN compared with IFN. The dose of IFN, which was initiated at 9 MIU 3 times a week in these trials, can be reduced to effectively manage IFN-related side effects without compromising the efficacy of bevacizumab plus IFN. Bevacizumab has good tolerability with manageable side effects, both alone and in combination with other agents; the tolerability profile of bevacizumab in combination with IFN is consistent with the well-characterized and well-established profiles of these therapies. The tolerability of bevacizumab combined with IFN and the flexibility to manage IFN-related side effects are important considerations when selecting first-line therapy. With a number of options now available for RCC therapy, optimizing their use is a key consideration in improving patient benefit.

Pathological tumour diameter predicts risk of conventional subtype in small renal cortical tumours

OBJECTIVE

To examine whether pathological tumour diameter assists in predicting conventional vs other histological subtypes in renal cortical tumours (RCTs) of <or=4 cm diameter.

PATIENTS AND METHODS

In all, 393 patients from Columbia University's Comprehensive Urologic Oncology Database who underwent radical or partial nephrectomy between 1988 and 2005 and had RCTs of <or=4 cm were analysed. Logistic regression analysis using tumour diameter as a continuous variable was used to determine whether size predicted histological subtype. Odds ratios (ORs) were calculated to estimate the likelihood of having conventional histology based on diameter.

RESULTS

The median patient age at surgery was 64.3 years and median tumour diameter was 3 cm, In all, 256 (65.1%) of the RCTs were conventional subtype and 137 (34.9%) were nonconventional. Logistic regression analysis showed that for every 1 cm increase in diameter up to 4 cm, the RCT was 1.27 times more likely to be conventional (P = 0.020). The ORs showed that a 4-cm RCT was 2.06 times more likely to be conventional than tumours of 0.6-1.5 cm.

CONCLUSION

There was a positive association between RCT diameter and the risk of having conventional renal cell carcinoma (RCC). Given that RCC histological subtype is a prognostic indicator for outcome, these findings may be applied in the selection of treatment options. Further studies investigating tumour size and other variables predictive of tumour histology will help clinicians better predict the RCC subtype.

Oncofetal protein IMP3: a novel molecular marker that predicts metastasis of papillary and chromophobe renal cell carcinomas

BACKGROUND

Whether an oncofetal protein, IMP3, can serve as a prognostic biomarker to predict metastasis for patients with localized papillary and chromophobe subtypes of renal cell carcinomas (RCCs) was investigated.

METHODS

The expression of IMP3 in 334 patients with primary papillary and chromophobe RCC from multiple medical centers was evaluated by immunohistochemistry. The 317 patients with localized papillary and chromophobe RCCs were further evaluated for outcome analyses.

RESULTS

IMP3 was significantly increased in a subset of localized papillary and chromophobe RCCs that subsequently metastasized. Patients with localized IMP3-positive tumors (n=33; 10%) were over 10 times more likely to metastasize (risk ratio [RR], 11.38; 95% confidence interval [CI], 5.40-23.96; P<.001) and were nearly twice as likely to die (RR, 1.91; 95% CI, 1.13-3.22; P=.016) compared with patients with localized IMP3 negative tumors. The 5-year metastasis-free and overall survival rates were 64% and 58% for patients with IMP3-positive localized papillary and chromophobe RCCs compared with 98% and 85% for patients with IMP3 negative tumors, respectively. In multivariable analysis adjusting for the TNM stage and nuclear grade, patients with IMP3-positive tumors were still over 10 times more likely to progress to distant metastasis (RR, 13.45; 95% CI, 6.00-30.14; P<.001) and were still nearly twice as likely die (RR, 1.95; 95% CI, 1.15-3.31; P=.013) compared with patients with IMP3-negative tumors.

CONCLUSIONS

IMP3 is an independent prognostic biomarker that can be used to identify a subgroup of patients with localized papillary and chromophobe RCC who are at high risk for developing distant metastasis.

Long-term outcome of multiple ipsilateral renal tumours found at the time of planned nephron-sparing surgery

OBJECTIVE

To evaluate patients with multiple ipsilateral renal tumours and to determine outcomes of nephron-sparing surgery (NSS) and radical nephrectomy (RN), as the treatment of unrecognized sporadic multifocal tumours at NSS presents a surgical dilemma.

PATIENTS AND METHODS

In all, 104 patients had surgery between 1970 and 2003 for sporadic multiple ipsilateral renal tumours, at least one of which was renal cell carcinoma (RCC); 114 were treated with RN and 26 with NSS. Cancer-specific survival (CSS) was estimated using the Kaplan-Meier method.

RESULTS

More patients treated with NSS had a solitary kidney than those undergoing RN (six, 23%, vs none, P < 0.001). Seventeen of the 114 having RN died from RCC at a median (range) of 3.4 (0.25-10.3) years after RN. The estimated 5-year CSS was 90.5%. There was metachronous recurrence in nine patients at a median of 5.6 (1-14 ) years after. Two of the 26 patients having NSS died from RCC at 1 and 6 years after NSS; the 5-year CSS was 95.8%. There was local or metachronous recurrence in three patients at 7 months to 6 years after surgery; all three were alive at the last follow-up. In 26 (23%) of the 114 patients treated with RN, only one tumour was RCC.

CONCLUSION

Patients undergoing either RN or NSS for multiple ipsilateral renal tumours have a favourable CSS. A planned NSS is safe if small satellite lesions are resectable.

Molecular diagnosis of renal cell neoplasms: the usefulness of immunohistochemistry and fluorescence in situ hybridization

BACKGROUND

The classification of renal cell neoplasms includes different subtypes of tumors characterized by different outcome. Some overlapping morphological features and the increasing recognition of new entities are making the traditional histologic distinction of renal cell neoplasms difficult and more tools improving the specificity of the correct identification are needed. Among molecular analyses, immunohistochemistry and fluorescence in situ hybridization have become the most helpful procedures, solving many issues in the differential diagnosis of the renal cell neoplasms.

OBJECTIVE

The aim of this review is to merge the large amount of recent knowledge regarding molecular markers of renal cell neoplasms into a helpful diagnostic algorithm.

CONCLUSION

It is proposed that immunoreactions for CD10, Alpha-methylacyl-CoA racemase, cytokeratin 7, parvalbumin and S100A1, and the cytogenetical analysis of chromosomes 3p, 1, 2, 6, 7, 10, 17 and Y can now offer the most specific tools for the classification of renal cell tumors.

Prognostic factors in a prospective series of papillary renal cell carcinoma

OBJECTIVE

To prospectively assess the clinical outcome of a series of papillary renal cell carcinomas (PRCCs) to identify possible prognostic clinical variables and tumour markers, as previous retrospective series of PRCC do not provide unanimous results on the prognostic utility of clinicopathological variables.

PATIENTS AND METHODS

Forty-six patients with PRCC (median follow-up 40 months) diagnosed in one institution from 1989 to 2002 were prospectively followed until May 2006. The pathology was reviewed, the PRCC subtyped (type 1 and 2) and immunohistochemistry assessed for MIB-1, vascular endothelial growth factor (VEGF), CD31 and c-met oncogenic protein, by a referee pathologist. Prognostic values were estimated by fitting a Cox model.

RESULTS

The 5-year survival rate was 49.5%; type 2 histology was predominant and was almost significant in the univariate analysis. Stage and MIB-1 were significant prognostic factors only in the univariate model, while the Cox model identified only the Fuhrman grade as an independent predictor of survival (hazard ratio 3.054; P = 0.007). MET expression, CD31 and VEGF had no prognostic utility.

CONCLUSION

These patients with PRCC followed prospectively fared worse than in previously reported series. The Fuhrman grade was the sole independent predictor of survival.

Analysis of clinicopathologic predictors of oncologic outcome provides insight into the natural history of surgically managed papillary renal cell carcinoma

BACKGROUND

To gain further insight into the natural history of papillary renal cell carcinoma (pRCC), the authors evaluated oncologic impact of important clinical and pathologic prognostic factors and performed survival analyses in a large group of contemporary patients surgically treated for pRCC.

METHODS

The institutional nephrectomy database was searched for patients who were managed with radical or partial nephrectomy for pRCC or clear cell RCC (cRCC) from 1994 to 2006.

RESULTS

A total of 2157 patients with pRCC (n=245) or cRCC (n=1912) met protocol inclusion criteria. Kaplan-Meier analyses revealed equivalent 5-year cancer-specific survival (CSS) in the nonmetastatic pRCC patient group and revealed significantly decreased CSS in pRCC patients with distant metastases compared with matched cRCC patient cohorts. Presence of venous tumor thrombus was associated with a significant decrease in CSS and was an independent prognostic feature in pRCC patient cohort but not in patients with cRCC (5-year CSS pRCC=35%; cRCC=66%; P= .012). Patients with pRCC were at a significantly increased risk of harboring metastatic lymph nodes compared with patients with cRCC (13% and 8.6%, respectively; P= .019); however, presence of lymph node metastases in patients with pRCC was associated with a relatively indolent disease course (5-year CSS pRCC=65%; cRCC=19%; P= .029).

CONCLUSIONS

The authors demonstrated significant differences in presentation, prognostic features, and patient outcomes among papillary and clear cell histologic subtypes of RCC. The authors' findings may potentially link unique molecular genetics that have been reported in pRCCs to its distinct clinical behavior.

A p120 catenin isoform switch affects Rho activity, induces tumor cell invasion, and predicts metastatic disease

p120 catenin is a cadherin-associated protein that regulates Rho GTPases and promotes the invasiveness of E-cadherin-deficient cancer cells. Multiple p120 isoforms are expressed in cells via alternative splicing, and all of them are essential for HGF signaling to Rac1. However, only full-length p120 (isoform 1) promotes invasiveness. This selective ability of p120 isoform 1 is mediated by reduced RhoA activity, both under basal conditions and following HGF treatment. All p120 isoforms can bind RhoA in vitro, via a central RhoA binding site. However, only the cooperative binding of RhoA to the central p120 domain and to the alternatively spliced p120 N terminus stabilizes RhoA binding and inhibits RhoA activity. Consistent with this, increased expression of p120 isoform 1, when compared with other p120 isoforms, is predictive of renal tumor micrometastasis and systemic progression, following nephrectomy. Furthermore, ectopic expression of the RhoA-binding, N-terminal domain of p120 is sufficient to block the ability of p120 isoform 1 to inhibit RhoA and to promote invasiveness. The data indicate that the increased expression of p120 isoform 1 during tumor progression contributes to the invasive phenotype of cadherin-deficient carcinomas and that the N-terminal domain of p120 is a valid therapeutic target.

Mucinous tubular and spindle cell carcinoma with aggressive histomorphology--a sarcomatoid variant

Mucinous tubular and spindle cell carcinoma (MTSCC) is a recently described renal epithelial tumor. The bland cytomorphology of the spindled component and low-grade behavior help in its differentiation from sarcomatoid renal carcinoma. Sarcomatoid change has been reported in most histologic variants of renal cell carcinoma apart from MTSCC. Herein we report a case of an MTSCC in a 72-year-old female patient with high-grade spindled areas resembling fibrosarcomatous and undifferentiated pleomorphic sarcoma patterns with metaplastic bone. This index case also demonstrates a high proliferation index and extensive necrosis representing the first documented case of sarcomatoid change in MTSCC.

Association of abnormal preoperative laboratory values with survival after radical nephrectomy for clinically confined clear cell renal cell carcinoma

OBJECTIVES

To determine whether preoperative laboratory values are independently associated with death from clinically confined clear cell renal cell carcinoma (RCC) after radical nephrectomy.

METHODS

We identified 1707 patients with clinically confined (pNx/pN0, pM0), unilateral, sporadic clear cell RCC treated with radical nephrectomy between 1970 and 2002. Associations of abnormal preoperative laboratory values including hypercalcemia, anemia, elevated erythrocyte sedimentation rate (ESR), and elevated alkaline phosphatase with death from RCC were evaluated using Cox proportional hazards regression models, both univariately and multivariately by adjusting for known prognostic features of the 2002 primary tumor classification, tumor size, nuclear grade, and coagulative tumor necrosis.

RESULTS

At last follow-up, 1009 patients had died, including 425 who died from RCC at a median of 3.0 years after surgery (range, 0 to 26 years). Even after adjusting for known prognostic features, 9% of patients with preoperative hypercalcemia exhibited significantly increased likelihood of dying from RCC compared with patients with normal or lower levels of serum calcium (relative ration [RR] 1.64; P = 0.002). Similarly, preoperative anemia (35% of patients; RR 1.27; P = 0.026) and elevated ESR (44% of patients; RR 1.66; P = 0.003) portended an increased risk of death from RCC even after multivariate adjustment.

CONCLUSIONS

Abnormal preoperative laboratory values including hypercalcemia, anemia, and elevated ESR are independently associated with increased risk of cancer-specific death from clinically confined clear cell RCC. Consideration of these variables in future models may improve prognostic accuracy. We believe these factors should be routinely assessed and included in prospective studies of outcome in RCC patients.

Risk stratification and prognostication of renal cell carcinoma

OBJECTIVES

To review the most recent data on prognostic factors and describe the characteristics and prognostic accuracy of the most important prognostic systems available to predict the risk of recurrence, progression, and mortality in patients with renal cell carcinoma (RCC).

METHODS

The study was based on a non-systematic review of literature.

RESULTS

Clinical (performance status, and mode of presentation), anatomical (size and extension of the primary tumor, lymph node involvement, and distant metastasis), and histological factors (histological subtypes, nuclear grade, and tumor necrosis) are the most largely evaluated prognostic factors in RCC. Valuable prognostic accuracy has been shown for several laboratory parameters (erythrocyte sedimentation rate, platelet count, serum calcium, hemoglobin, and lactate dehydrogenase levels) and a few genetical and molecular markers (CAIX, B7-H1, and B7-H4). A few integrating systems have been proposed and validated, integrating both clinical and pathological (UCLA Integrating Staging Systems, Kattan nomogram, and Sorbellini nomogram) or only pathological variables (SSIGN score).

CONCLUSIONS

Several large and methodologically consistent studies have been published. The chance to integrate the data derived from each prognostic factor into prognostic algorithms and scores has allowed improving significantly the stratification of the prognosis of patients with RCC. The currently available prognostic systems can be further improved through the inclusion of molecular and genetic variables. Integrating prognostic systems should be used to design randomized controlled trials (RCTs), which will evaluate the efficacy of the new-targeted therapies in either neoadjuvant, adjuvant, or salvage treatments of patients with RCC.

Interphase cytogenetic analysis with centromeric probes for chromosomes 1, 2, 6, 10, and 17 in 11 tumors from a patient with bilateral renal oncocytosis

Renal oncocytosis is characterized by the presence of multiple tumors with oncocytic features, often associated with small clusters of tubule-like structures with oncocytic change. The morphologic features of the oncocytic nodules encompass a spectrum of appearances, with patterns typical of renal oncocytoma or classic chromophobe renal cell carcinoma, as well as 'hybrid' tumors with features resembling both oncocytoma and chromophobe renal cell carcinoma. We utilized interphase cytogenetic methods to study 11 tumors from the kidneys of a 45-year-old woman. The tumors included morphologically classical oncocytomas and 'hybrid' tumors with features reminiscent of chromophobe carcinoma. The kidneys also showed foci of oncocytic change in renal tubules. Fluorescence in situ hybridization was performed with centromeric probes for chromosomes 1, 2, 6, 10, and 17 in each of the 11 tumors to determine whether or not there were losses of the chromosomes that are most frequently lost in chromophobe renal cell carcinomas. Neoplastic nuclei from each tumor were evaluated for the number of hybridization signals and scored according to the percentage of nuclei with one, two, and three or more signals. The normal renal parenchyma surrounding the tumors was used as control tissue. All 11 tumors from this patient with renal oncocytosis showed no loss of any of the chromosomes 1, 2, 6, 10, or 17, a pattern identical to that found in normal control tissues. These observations weigh against the concept that hybrid tumors of oncocytosis are closely related to chromophobe renal cell carcinoma.

Mathematical models for prognostic prediction in patients with renal cell carcinoma

OBJECTIVES

The objectives of this study are to catalogue all models developed to predict survival of RCC patients and to identify the ones to be used in different situations.

METHODS

A systematic review was performed searching with a free text and MeSH strategy 3 electronic databases. For each model, the following parameters were identified: number, features of the patients; evaluation endpoints; clinical and/or pathological variables included; concordance indexes (cI).

RESULTS

The research retrieved 156 records. Eleven articles proposed new models, 5 articles external validations. We retrieved 2 mathematical models including clinical variables only (Yaycioglu, cI 0.651; Cindolo, cI 0.672); 2 algorithms including also pathological variables (SSIGN, cI 0.819; UISS, cI 0.79-0.84), 5 nomograms (Kattan, cI 0.76-0.86; Sorbellini, cI 0.82; Kim 2004, cI 0.79, Kim 2005, cI 0.68; Karakiewicz, cI 0.86); 2 algorithms for patients with metastatic disease (Motzer, Leibovich).

CONCLUSIONS

The SSIGN was the most accurate algorithm for conventional RCC, while the UISS allowed the evaluation of patients regardless of tumor histotype. The Sorbellini nomogram is applicable only for patients with conventional RCC, while the Kattan and Karakiewicz nomograms also provide information for other histotypes. Metastatic patients can be evaluated with Leibovich and Motzer algorithms. Two models combine molecular markers and clinical features (Kim 2004-2005).

Combined expression of caveolin-1 and an activated AKT/mTOR pathway predicts reduced disease-free survival in clinically confined renal cell carcinoma

We previously reported that tumour-associated caveolin-1 is a potential biomarker in renal cell carcinoma (RCC), whose overexpression predicts metastasis following surgical resection for clinically confined disease. Much attention has recently focused on the AKT/mTOR pathway in a number of malignancies, including RCC. Since caveolin-1 and the AKT/mTOR signalling cascade are independently shown to be important regulators of tumour angiogenesis, we hypothesised that caveolin-1 interacts with the AKT/mTOR pathway to drive disease progression and metastasis in RCC. The aims of this study were to determine (i) the expression status of the activated AKT/mTOR pathway components (phosphorylated forms) in RCC and (ii) their prognostic value when combined with caveolin-1. Immunohistochemistry for caveolin-1, pAKT, pmTOR, pS6 and p4E-BP1 was performed on tissue microarrays from 174 clinically confined RCCs. Significantly decreased mean disease-free survival was observed when caveolin-1 was coexpressed with either pAKT (2.95 vs 6.14 years), pmTOR (3.17 vs 6.28 years), pS6 (1.45 vs 6.62 years) or p4E-BP1 (2.07 vs 6.09 years) than when neither or any one single biomarker was expressed alone. On multivariate analysis, the covariate of ‘caveolin-1/AKT’ (neither alone were influential covariates) was a significant influential indicator of poor disease-free survival with a hazard ratio of 2.13 (95% CI: 1.15–3.92), higher than that for vascular invasion. Tumours that coexpressed caveolin-1 and activated mTOR components were more likely to be larger, higher grade and to show vascular invasion. Our results provide the first clinical evidence that caveolin-1 cooperates with an activated AKT/mTOR pathway in cancer and may play an important role in disease progression. We conclude that evaluation of the ‘caveolin-1/AKT/mTOR axis’ in primary kidney tumours will identify subsets of RCC patients who require greater postoperative surveillance and more intensive treatment.

Differences in organ system of distant metastasis by renal cell carcinoma subtype

PURPOSE

The majority of the published data regarding the rates of renal cell carcinoma metastasis to specific locations has examined renal cell carcinoma as a whole. We evaluated site of distant metastasis by renal cell carcinoma histological subtype.

MATERIALS AND METHODS

We studied 910 patients treated with radical nephrectomy for clear cell, papillary or chromophobe renal cell carcinoma at the Mayo Clinic between 1970 and 2000 who had distant metastasis at nephrectomy or who had metastasis during followup. The sites of metastases were compared by histological subtype using the chi-square and Fisher exact tests.

RESULTS

There were 853 (94%) patients with clear cell, 39 (4%) with papillary and 18 (2%) with chromophobe renal cell carcinoma. Median followup for the 65 patients who were still alive at last followup was 11.6 years. Patients with clear cell renal cell carcinoma were more likely to have metastasis to the lungs (53.6%) compared to those with papillary (33.3%) and chromophobe (33.3%) renal cell carcinoma (p = 0.012). Patients with chromophobe renal cell carcinoma were more likely to have metastasis to the liver compared to those with clear cell renal cell carcinoma (33.3% vs 9.7%, p = 0.007), but there was not a statistically significantly difference in the incidence of liver metastases between patients with chromophobe and papillary renal cell carcinoma (33.3% vs 18.0%, p = 0.308).

CONCLUSIONS

Site of distant metastasis varies significantly by renal cell carcinoma histological subtype. Patients with clear cell renal cell carcinoma are more likely to have metastasis to the lungs while patients with chromophobe renal cell carcinoma are more likely to experience liver metastasis.

Identification of Toll-like receptor 3 as a potential therapeutic target in clear cell renal cell carcinoma

PURPOSE

Renal cell carcinoma (RCC) is one of the most drug-refractory cancers. The aim of this study is to discover a novel therapeutic target molecule for clear cell RCC (CCRCC), which accounts for the majority of RCC.

EXPERIMENTAL DESIGN

Gene expression profiles of 27 CCRCCs and 9 normal kidney tissues as well as 15 various adult normal tissues were examined by Affymetrix U133 Plus 2.0 arrays. Among the 34 genes specifically up-regulated in CCRCC, overexpression of Toll-like receptor 3 (TLR3) mRNA and its protein was validated by quantitative reverse transcription-PCR, immunoblot, and immunohistochemistry. The effects of TLR3 signaling on in vitro cell growth were examined.

RESULTS

TLR3 gene was highly expressed in CCRCC, with only limited expression in a panel of normal tissues. On immunohistochemical analysis using a monoclonal antibody against TLR3, overexpression of TLR3 was observed in 139 of 189 (73.5%) cases of CCRCC as well as in lung metastatic CCRCC (6 of 8), whereas TLR3 expression was entirely absent in chromophobe RCC (0 of 8). Polyinosinic-polycytidilic acid, a TLR3 ligand, exerted a growth-inhibitory effect against RCC cells in a TLR3-dependent manner. Moreover, a combination of polyinosinic-polycytidilic acid and IFNalpha exerted a synergistic growth-inhibitory effect against Caki-1 RCC cells.

CONCLUSIONS

This is the first report that TLR3 is overexpressed in CCRCC. These observations suggest that TLR3 pathway may represent a novel therapeutic target in CCRCC.

Genetics and epigenetics of renal cell cancer

Renal cell carcinoma (RCC) is not a single disease, but comprises a group of tumors of renal epithelial origin, each with a different histology, displaying a different clinical course and caused by different genetic alterations. Since cure rates are inversely associated with stage and response to the available treatment regimes is limited to a subgroup of patients, diagnostic methods facilitating early detection and new therapeutic modalities are necessary. Increased knowledge of the underlying pathophysiology of RCC has resulted in the identification of genetic alterations involved in renal cell cancer carcinogenesis. Promising agents to target these pathways, especially the angiogenesis pathway, are being developed, some of which are already standard of care. In addition to genetics, knowledge on epigenetics in the process of renal tumorigenesis has been significantly increased in the last decades. Epigenetics will play an increasing role in the development of new therapeutic modalities and may deliver new prognostic and early diagnostic markers. In this review we discuss the background of RCC and the clinical applications of RCC genetics and epigenetics.

The Prevalence of Malignancy in Satellite Renal Lesions and its Surgical Implication During Nephron Sparing Surgery

PURPOSE

We examined the prevalence of malignancy in a synchronous ipsilateral renal lesion identified during partial nephrectomy and evaluated its clinical significance.

MATERIALS AND METHODS

We retrospectively reviewed the records of 112 patients (114 renal units) who underwent nephron sparing surgery for a clinically localized sporadic renal mass between May 1995 and September 2005.

RESULTS

In 37 patients (32%) an additional lesion was diagnosed and excised intraoperatively, while in 67% these lesions were known before the operation and believed to be simple cysts. During surgery the additional mass was suspicious in 8 cases and in the remainder the mass was described as simple cysts that were excised. The mean size of the primary mass was 3.1 cm (SD 1.4). In 29 (78%) cases the primary mass was malignant, in 23 (79%) of these the second mass was benign and in the remainder renal cell carcinoma was diagnosed. In 8 cases (22%) the primary mass was benign and in 2 (25%) the secondary mass was malignant. Overall 22% of all second masses were malignant, and all were low grade and low stage. We found that 7% of second ipsilateral masses could be expected to harbor malignancy.

CONCLUSIONS

Based on our data it is questionable whether total nephrectomy is mandatory as an immediate response to an ipsilateral synchronous second renal mass. The present findings may represent an increased appreciation of ipsilateral multicentricity compared to historical data.

Carbonic Anhydrase IX Is Not an Independent Predictor of Outcome for Patients With Clear Cell Renal Cell Carcinoma

Purpose

Expression of carbonic anhydrase IX (CAIX) has been reported to be an independent predictor of outcome and is being investigated as a therapeutic target for patients with clear cell renal cell carcinoma (ccRCC). We attempted to validate the prognostic utility of CAIX expression using a large cohort of ccRCC patients with long-term follow-up.

Patients and Methods

We identified 730 patients with unilateral, sporadic ccRCC treated surgically between 1990 and 1999. Anti-CAIX monoclonal antibody (clone M75) was used, and tumor specimens were blindly scored for expression levels. Associations of CAIX expression with RCC death were evaluated using Cox proportional hazards regression models.

Results

There were 241 RCC deaths and a median of 9.4 years of follow-up for patients still under observation. CAIX was expressed in 708 (97.0%) of the specimens; 163 tumors (22.3%) exhibited low (≤ 85% tumor cells positive) expression, and 567 (77.7%) exhibited high (> 85% tumor cells positive) expression. Univariately, low CAIX expression was associated with increased risk of RCC death relative to high expression (risk ratio = 1.65; P < .001). However, low CAIX expression was not associated with RCC death after adjusting for nuclear grade or coagulative tumor necrosis. Additionally, we observed CAIX expression in a number of extrarenal organs.

Conclusion

CAIX is strongly expressed by ccRCC. Although CAIX is associated with outcome in patients with ccRCC, it is not an independent prognostic marker. Furthermore, CAIX expression is apparent in extrarenal organs. As such, exploitation of CAIX as a prognostic marker and therapeutic target merits additional consideration.

Outcome prediction for renal cell carcinoma: evaluation of prognostic factors for tumours divided according to histological subtype

A wide variety of parameters have been investigated for their prognostic significance in mixed series of renal cell carcinoma (RCC). The classification of RCC into separate types with differing morphology, genotype and probable clinical outcome has led to a re-evaluation of many prognostic parameters with studies confined to a single RCC morphotype. Tumour stage remains the most important predictor of RCC outcome and recent investigations have focused upon tumour diameter and the prognostic significance of stromal, vascular and lymphatic invasion within the renal sinus. In large tumour series, morphotype has been correlated with patient survival, with clear cell RCC being associated with a less favourable outcome than chromophobe RCC and to a lesser extent papillary RCC, for organ confined tumours. The prognostic significance of nuclear grading remains controversial. Fuhrman grading has been shown to have prognostic utility for clear cell RCC in some series. Recent studies have shown that for papillary RCC, grading should be based upon nucleolar size and that Fuhrman grading is inappropriate for chromophobe RCC. Proliferative indices based upon a variety of markers have been correlated with outcome for clear cell RCC (Ki-67, AgNORs, p21(waf1/cip1) and p27(Kip1)) and papillary RCC (Ki-67, AgNORs), although in some series prognostic significance was lost on multivariate analysis. The presence of tumour necrosis has been shown to predict survival for clear cell and chromophobe RCC, and in clear cell RCC quantification of tumour vascular density has been correlated with outcome. Several molecular markers have been investigated for prognostic significance, mostly in clear cell RCC. Although some of these markers have been shown to be significantly associated with survival, these findings remain to be confirmed in large scale follow-up studies.

MR classification of renal masses with pathologic correlation

To perform a feature analysis of malignant renal tumors evaluated with magnetic resonance (MR) imaging and to investigate the correlation between MR imaging features and histopathological findings. MR examinations in 79 malignant renal masses were retrospectively evaluated, and a feature analysis was performed. Each renal mass was assigned to one of eight categories from a proposed MRI classification system. The sensitivity and specificity of the MRI classification system to predict the histologic subtype and nuclear grade was calculated. Subvoxel fat on chemical shift imaging correlated to clear cell type (p < 0.05); sensitivity = 42%, specificity = 100%. Large size, intratumoral necrosis, retroperitoneal vascular collaterals, and renal vein thrombosis predicted high-grade clear cell type (p < 0.05). Small size, peripheral location, low intratumoral SI on T2-weighted images, and low-level enhancement were associated with low-grade papillary carcinomas (p < 0.05). The sensitivity and specificity of the MRI classification system for diagnosing low grade clear cell, high-grade clear cell, all clear cell, all papillary, and transitional carcinomas were 50% and 94%, 93% and 75%, 92% and 83%, 80% and 94%, and 100% and 99%, respectively. The MRI feature analysis and proposed classification system help predict the histological type and nuclear grade of renal masses.

Ki-67 and coagulative tumor necrosis are independent predictors of poor outcome for patients with clear cell renal cell carcinoma and not surrogates for each other

BACKGROUND

Ki-67 is a cell proliferation protein associated with aggressive clear cell renal cell carcinoma (ccRCC). A recent report suggests that Ki-67 may represent a surrogate marker for coagulative tumor necrosis. Thus, the goal was to directly test whether Ki-67 and necrosis convey similar or distinct information for the prognostic assessment of ccRCC.

METHODS

Tumor specimens from 741 consecutively treated patients who underwent surgery for ccRCC between 1990 and 1999 were evaluated. Tumor specimens were assessed for various clinicopathologic features, including levels of tumor cell Ki-67 expression. Associations of these features with death from RCC were evaluated using Cox proportional hazards regression models.

RESULTS

At last follow-up, 396 patients had died, including 238 who died from ccRCC at a median of 2.1 years after surgery. Although tumor cell Ki-67 expression and coagulative tumor necrosis were highly correlated, the prognostic information conveyed by these 2 markers failed to overlap. For the subset of patients with necrotic tumors, high levels of Ki-67 more than doubled the risk of death from RCC (risk ratio, 2.18; 95% confidence interval [CI], 1.52-3.11; P < .001). For patients with tumors lacking necrosis, high levels of Ki-67 expression were similarly correlated with an increased risk of death from RCC (risk ratio, 2.50; 95% CI, 1.66-3.77; P < .001).

CONCLUSIONS

Prognostic information conveyed by Ki-67 and coagulative tumor necrosis are not interchangeable. Thus, Ki-67 and coagulative tumor necrosis should not be treated as surrogates for one another and both of these features should be evaluated when generating outcome predictions for patients with ccRCC.

Drug Insight: advances in renal cell carcinoma and the role of targeted therapies

In metastatic renal cell carcinoma (RCC) immunotherapy results in a small but important improvement in overall survival, but a need exists to develop more-effective systemic therapies. Recent developments in our understanding of the molecular biology of RCC have identified several pathways associated with the development of the disease. A number of strategies designed specifically to target these pathways have resulted. Initial studies have shown marked clinical benefits of so-called 'targeted therapies'. Sunitinib, sorafenib and axitinib are kinase inhibitors that inhibit the VEGF, platelet-derived growth factor and c-kit receptor tyrosine kinases. Bevacizumab is a monoclonal antibody that is directed against VEGF. Temsirolimus inhibits the mammalian target of rapamycin. These agents have all shown considerable activity with manageable toxicity in phase II and III studies in both previously treated and untreated patients. In phase III studies, sorafenib and bevacizumab have been associated with prolonged progression-free survival compared with placebo. Phase III data have shown improvements in progression-free and overall survival with sunitinib and temsirolimus, respectively, compared with interferon alfa. Additional studies are needed to determine the optimum utilization of these agents at the appropriate stage of disease and in the best combinations for maximal clinical benefit.

Recently Described and Emphasized Entities of Renal Neoplasms

Context.—Recent advances of molecular biology and cytogenetics of renal cancer have resulted in the new classification of renal neoplasms and a number of subtypes are identified and emphasized. In addition, rare nonepithelial renal neoplasms are identified and characterized. Familiarity with these entities will help make the most accurate diagnosis and guide the treatment and follow-up of patients with renal neoplasm.

Objective.—To review the clinicopathologic entities of renal neoplasms that are recently defined or emphasized. Their clinical, gross, microscopic, and immunohistochemical features, as well as specific cytogenetic or molecular abnormalities, are discussed. Important differential diagnoses of each entity are also briefly discussed.

Data Sources.—Extensive review of published literature and our experience.

Conclusions.—A number of new entities of renal neoplasms or genetically defined renal cell carcinomas have been identified or emphasized because of their unique genetic or molecular changes. Recognition of these entities becomes important as some of them have different biologic behavior and treatment strategies may be different.

Second Prize: Frequency of Benign Renal Cortical Tumors and Histologic Subtypes Based on Size in a Contemporary Series: What to Tell our Patients

BACKGROUND AND PURPOSE

Historically, 85% to 90% of renal masses have been malignant, with the majority being renal-cell carcinoma. However, with the increasing frequency of incidentally discovered renal masses, only 70% to 85% of lesions are found to be malignant. Furthermore, the pathologic breakdown of these lesions on the basis of size is not well described. This study sought to determine the incidence of the various histologic subtypes of renal cortical tumors according to size in a contemporary series of surgically treated patients.

MATERIALS AND METHODS

Our prospectively collected database of all 482 patients who underwent partial or radical nephrectomy for a unilateral, unifocal, suspicious renal cortical tumor between January 2001 and October 2005 was reviewed. The frequency of benign and malignant lesions was determined according to size, as was the incidence of the various histologic subtypes.

RESULTS

Of the lesions, 228 were <or=4 cm, and 254 were >4 cm. Of all lesions <or=4 cm, 26.3% were benign, whereas only 8.3% of the lesions >4 cm were benign. For larger lesions, 10.9% of those between 4 and 7 cm and only 5.6% of those >7 cm were benign (P < 0.001). A significant difference between histologic subtypes according to size also was found (P = 0.01). Smaller lesions (<or=4 cm) that proved to be malignant were less likely than larger lesions to be of clear-cell histology (50.0% v 72.8%) and more likely to be papillary (15.8% v 9.4%).

CONCLUSIONS

This study examined the largest contemporary database evaluating the histologic type of renal lesions according to size. Approximately one fourth (26.3%) of lesions <or=4 cm and 16.8% of lesions overall were benign, percentages higher than those reported in older series. Importantly, there was a higher incidence of benign and papillary lesions and a lower incidence of clear-cell histology in smaller lesions. Given the differences in the biological behavior of the various histologic subtypes of these tumors, these data are important when counseling patients about the treated and untreated natural history of small renal masses.

[Molecular biology of the clear cell renal cell carcinoma: principles for a selective treatment]

Renal cell carcinoma (RCC) and its most frequent subtype, the clear cell hystology type, has shown resistance to chemotherapy and radiotherapy treatment when disease was already spread in patients. Recently, a huge advance in the molecular biology of this tumor has been performed. This fact allowed a deeper and better knowledge of the disease and the development of new drugs that work against the growth factors involved in tumor origin. In this review article it is summarized the molecular milestones that are involved in the development of clear cell renal cell carcinomas.