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

Papillary renal carcinoma: Diagnostic approach by chemical shift gradient-echo and echo-planar MR imaging

PURPOSE

To elucidate whether MRI can detect fat in interstitial histiocytes and hemosiderin (Hs) deposition (both of which are histological characteristics of papillary renal carcinoma (RCpap)) within RCpap.

MATERIALS AND METHODS

Preoperative MR images of nine surgically confirmed RCpap and 57 clear cell renal carcinoma (RCcc) cases were retrospectively studied. Solid components of the lesions were evaluated. For fat detection, signal reduction on opposed-phase images of chemical shift MRI (CSI) was used. For Hs detection, signal reduction on echo-planar images or in-phase images of CSI was used. The prevalence of fat and Hs detection was compared between RCpap and RCcc.

RESULTS

In five of nine RCpap (54%), and 38 of 57 RCcc (67%), the presence of fat within the tumor was suggested by CSI (P = 0.71). Hs deposition within tumors was suggested by either EPI or CSI in nine of nine RCpap (100%), and 28 of 57 RCcc (51%) (P = 0.0036). Hs in RCpap was observed without or apart from necrosis or hemorrhage, whereas Hs in RCcc was located predominantly around necrosis.

CONCLUSION

Detecting intratumoral Hs by EPI or CSI, particularly that unrelated to necrosis or hemorrhage, may help differentiate RCpap from RCcc.

Cholangiocarcinoma at the cystic duct discovered by lymph node metastases with clear cell transformation

We encountered a case with cholangiocarcinoma of the cystic duct, which was first manifested by multiple lymph node metastases with clear cell changes resembling clear cell adenocarcinoma (CCC). Because the clear cell changes were not prominent at the primary site, clear cell transformation might have occurred preferentially at the metastatic lesion in this case. Alternatively, tumor cells with clear cell transformation, found at the primary site, might have high metastatic potential. The patient showed thromboembolism and hypercalcemia as paraneoplastic syndromes at the terminal stage as reported in patients with CCC of the ovary. Those complications might be common biological features of CCC.

Immunohistochemical Analysis of Mucinous Tubular and Spindle Cell Carcinoma and Papillary Renal Cell Carcinoma of the Kidney

Mucinous tubular and spindle cell carcinoma, a rare, recently described distinctive subtype of renal cell carcinoma, may have some morphologic similarities to the more common papillary renal cell carcinoma, particularly the basophilic (type 1) tumors with prominent solid growth pattern. Tumor circumscription, compact tubular architecture, focal papillations, mucin production and foam cells (features seen in both papillary renal cell carcinoma and mucinous tubular and spindle cell carcinoma), as well as spindle cell morphology, have resulted in some cases sent to us in consultation with a question of possible sarcomatoid papillary renal cell carcinoma. In this study, tissue microarrays with triplicate samples each from 27 mucinous tubular and spindle cell carcinomas and 20 papillary renal cell carcinomas were created to simulate experience in renal biopsy specimens. From immunohistochemistry (IHC) data, published in the contemporary literature, a panel consisting of alpha-methylacyl-CoA racemase (AMACR), cytokeratin 7 (CK7), epithelial membrane antigen (EMA), renal cell carcinoma marker (RCC Ma), CD10, high molecular weight cytokeratin (HMWK), and c-kit was designed to test its utility in differential diagnosis. The immunoreactivity in mucinous tubular and spindle cell carcinoma was AMACR 93%, CK7 81%, EMA 95%, RCC Ma 7%, CD10 15%, HMWK 15%, and c-kit 5% and in papillary renal cell carcinoma was AMACR 95%, CK7 65%, EMA 88%, RCC Ma 25%, CD10 80%, HWMK 15%, and c-kit 18%. This largest study to date on IHC of mucinous tubular and spindle cell carcinoma dispels the specificity of AMACR for papillary renal cell carcinoma among the RCC subtypes. The histogenesis of mucinous tubular and spindle cell carcinoma from the distal nephron continues to be debatable, as our study showed the expression of the proximal convoluted tubule-related marker AMACR among these tumors. Thus, in tumors with predominant compact tubular growth and focal papillary architectures, careful attention to the presence of a low-grade spindle cell population may be helpful in the distinction of mucinous tubular and spindle cell carcinoma, as the key immunohistochemical stains for papillary renal cell carcinoma are also expressed in this subtype of renal cell carcinoma.

Aplicación clínica de las actuales clasificaciones del cáncer renal

The purpose of classifying neoplasias is to recognize groups with similar progress and prognosis and, if possible, receiving the same treatment. This is why those classifications are systematically being submitted to review and improvement through the new technologies. Differentiation of various entities in renal cancer has been comparatively fast, as the new genetic and molecular discoveries have confirmed the morphologic criteria of the different cell types, thus making it possible to open new therapeutic pathways. Using the current WHO classification we recognize subtypes with excellent prognosis (Multilocular cystic renal carcinoma, Type I renal papillary carcinoma, Tubular and fusocellular mucinous carcinoma), other very aggressive ones (Bellini's collecting duct carcinoma, Medullary carcinoma), and also that the sarcomatoid transformation, even in small areas, impacts the prognosis negatively. Childhood-characteristic renal carcinomas associated with chromosome translocations have been recognized (genetic fusion TFE3 or TFEB), as well as the family forms of renal carcinoma. Regarding the UICC (International Union Against Cancer) classification, there are a series of aspects under argument (size, venous invasion, microvascular invasion, invasion of the adipous tissue of the renal sinus) that shall be discussed too, since it is possible that some modifications of the TNM might occur in the near future.

Thrombocytosis as a prognostic factor for survival in patients with metastatic renal cell carcinoma

BACKGROUND

It has been suggested that thrombocytosis, as defined by a platelet count >400,000/microL, is a negative predictor for survival among patients with metastatic renal cell carcinoma. However, this has not been a uniform finding.

METHODS

To address this issue, retrospective analysis of 700 previously untreated patients entering on institution review board-approved phase 1, 2, or 3 clinical trials in the United States and Europe was conducted between 1982 and 2002.

RESULTS

Thrombocytosis was present at study entry in 25% of patients. Median baseline platelet count was 304,000/microL (range, 86-1,420,000/microL). Eighty-seven percent of patients died with a median survival of 13.0 months. Median follow-up for patients not known to have died was 2.4 years. On univariate analysis, patients with elevated platelet counts had significantly shorter survival than patients with normal platelet counts; median survivals of 8.4 and 14.6 months, respectively, P < .001. However, platelet count was associated with several clinical and biochemical factors, including gender, age, performance status, time from diagnosis to study entry, prior radiotherapy or nephrectomy, presence of liver metastasis, number of metastatic sites, amount of hemoglobin, white blood cell count, amount of lactate dehydrogenase, and amount of serum alkaline phosphatase. Several of these factors have previously been reported as prognostic indicators for survival, and, therefore, multivariable analyses were conducted to determine whether thrombocytosis is an independent predictor of survival. After adjusting for multiple factors, thrombocytosis continued to impact negatively on survival, P < .001.

CONCLUSIONS

Thrombocytosis was found to be an independent prognostic factor for survival in patients with metastatic renal cell carcinoma.

Mononuclear cell infiltration in clear-cell renal cell carcinoma independently predicts patient survival

BACKGROUND

The impact of mononuclear cell infiltration on renal cell carcinoma (RCC) biology has been controversial, previously reported to be associated with either a favorable or unfavorable prognosis. The objective of the current study was to evaluate associations between mononuclear cell infiltration in routinely prepared paraffin-embedded specimens with survival in patients with clear-cell RCC.

METHODS

A total of 306 patients were identified treated with nephrectomy for clear-cell RCC between 1990 and 1994. A single urologic pathologist, blinded to patient outcome, reviewed the specimens and quantified the extent of mononuclear cell infiltration as absent, focal, moderate, or marked. Cancer-specific survival was estimated using the Kaplan-Meier method. Associations of mononuclear cell infiltration with death from RCC were assessed using Cox proportional hazards regression models.

RESULTS

At last follow-up, 173 of the 306 patients studied had died, including 96 patients who died from RCC. Mononuclear cell infiltration was absent in 165 (54%), focal in 70 (23%), moderate in 53 (17%), and marked in 18 (6%). Univariately, patients with specimens that had mononuclear cell infiltration were over 2 times more likely to die from RCC compared with patients whose specimens exhibited no mononuclear cell infiltration (risk ratio, 2.63; P < .001). After adjusting for the Mayo Clinic SSIGN (stage, size, grade, and necrosis) score, patients with specimens that had mononuclear cell infiltration exhibited a significantly increased likelihood of dying from RCC compared with patients whose specimens had no mononuclear cell infiltration (risk ratio, 1.61; P = .028).

CONCLUSIONS

Mononuclear cell infiltration is associated with death from RCC even after multivariate adjustment. Routine documentation of mononuclear cell infiltration is recommended during the pathologic assessment of RCC.

Chromophobe renal cell carcinoma: comprehensive analysis of 104 cases from multicenter European database

OBJECTIVES

To analyze the clinical behavior of chromophobe renal cell carcinoma (CRCC), we retrospectively evaluated the data from six European centers. In 1985, CRCC was identified as a new RCC histologic subtype. Because of its low frequency, only few large CRCC series are available.

METHODS

We created a renal cancer database including 3228 patients who underwent surgery between 1986 and 2002 in six European centers. The relevant clinical and pathologic data were extracted from the clinical charts at each institution and collected into a unique database.

RESULTS

Of the 3228 patients, 104 (3.2%) affected by CRCC were identified. The mean age at diagnosis was 57.6 years (range 22 to 83). Of the 104 patients, 51 (49%) were men and 53 (51%) were women. The mean tumor size was 6.4 +/- 3.6 cm. An incidental diagnosis accounted for 61.5% of the cases. Radical nephrectomy was performed in 88 patients (85%). After a median follow-up of 38 months (mean 44, range 1 to 153), no local recurrence was observed. The 5-year overall survival rate for CRCC was 81%. Of the 104 patients, 5 (4.8%) and 9 (8.6%) died of unrelated causes and renal cancer, respectively.

CONCLUSIONS

Our series confirmed a favorable outcome for the CRCC subtype with little local aggressiveness and a low propensity for progression and death from cancer.

A scoring algorithm to predict survival for patients with metastatic clear cell renal cell carcinoma: a stratification tool for prospective clinical trials

PURPOSE

We developed a clinically useful scoring algorithm to predict cancer specific survival for patients with clear cell metastatic renal cell carcinoma (RCC).

MATERIALS AND METHODS

We studied 727 patients treated with radical nephrectomy for clear cell RCC from 1970 to 2000 who had distant metastases at nephrectomy (285) or in whom metastases subsequently developed (442). A scoring algorithm to predict cancer specific survival was developed using the regression coefficients from a Cox proportional hazards model.

RESULTS

There were 606 deaths from clear cell RCC at a median of 1.0 years (range 0 to 14) following metastatic RCC. Constitutional symptoms at nephrectomy (+2), metastases to the bone (+2) or liver (+4), metastases in multiple simultaneous sites (+2), metastases at nephrectomy (+1) or within 2 years of nephrectomy (+3), complete resection of all metastatic sites (-5), tumor thrombus level I to IV (+3), and the primary pathological features of nuclear grade 4 (+3) and histological tumor necrosis (+2) were significantly associated with death from RCC. All patients started with a score of 0 and points were added or subtracted as indicated in parentheses. Cancer specific survival rates at 1 year were 85.1%, 72.1%, 58.8%, 39.0%, and 25.1%, respectively, for patients with scores of -5 to -1, scores of 0 to 2, scores of 3 to 6, scores of 7 or 8, and scores of 9 or more.

CONCLUSIONS

This scoring algorithm can be used to predict cancer specific survival for patients with metastatic clear cell RCC.

Clear cell renal cell carcinoma: gene expression analyses identify a potential signature for tumor aggressiveness

PURPOSE

The objective of this study was to use gene expression profiling to identify novel biomarkers that are predictive of aggressive behavior in clear cell renal cell carcinoma (CCRCC).

EXPERIMENTAL DESIGN

Candidate genes were discovered using Human Genome U133 Plus 2 Arrays and validated on independent samples by quantitative reverse transcription-PCR (RT-PCR). Both the discovery and the validation cohorts included nonaggressive primary CCRCC, aggressive primary CCRCC, metastatic CCRCC, and nonneoplastic kidney adjacent to tumor.

RESULTS

Aggressive primary and metastatic CCRCC displayed no significant differences in gene expression. In contrast, we identified significant differences in gene expression between nonaggressive and aggressive CCRCC (including metastatic CCRCC). Thirty-four of the 35 transcripts that displayed the most significant differential expression by microarray analysis also displayed significant differential expression in independent validation studies using quantitative RT-PCR (P < 0.001 for 31 candidates and P < 0.005 for the remaining three candidates). Hierarchical clustering of the quantitative RT-PCR data using our candidate markers accurately grouped 88% (23 of 26) of aggressive and metastatic CCRCC samples, 100% (14 of 14) of nonaggressive CCRCC samples, and 100% (15 of 15) of nonneoplastic samples into separate clusters. Finally, we evaluated the ability of protein expression levels of one of our candidate markers (survivin) to predict survival among a cohort of 183 CCRCC patients treated surgically at Mayo Clinic from 1990 to 1992. In multivariate analysis, expression of survivin (BIRC5) was inversely associated with cancer-specific survival (P = 0.017).

CONCLUSION

We used a combination of genomic profiling and validation by quantitative PCR to identify a panel of candidate biomarkers for determining CCRCC aggressiveness. Our data also indicate that the gene expression alterations that result in aggressive behavior and metastatic potential can be identified in the primary tumor.

Lessons learned in the surgical management of renal cell carcinoma

Surgical excision, the mainstay of management of renal cell carcinoma (RCC), has evolved significantly over the last 4 decades. Radiological imaging is crucial to the diagnosis and staging of RCC, and technological advances have facilitated more precise preoperative assessment. Additionally, wider use of cross-sectional imaging modalities has led to increasing incidental diagnosis of small, early-stage RCC. Nephron-sparing surgery (NSS), originally developed to treat RCC arising in a solitary functioning kidney, has been demonstrated to be a safe and effective alternative to radical nephrectomy. NSS is now also applicable to tumors of suitable size and anatomy in patients with a normal contralateral kidney, thus facilitating preservation of renal function and management of metachronous contralateral pathology. Laparoscopic and percutaneous approaches have developed over the last decade, thus providing minimally invasive modalities, with shortened convalescence and improved cosmesis. Advanced RCC, involving venous extension or nodal spread, is increasingly amenable to surgical management, although appropriate patient selection is crucial. Furthermore, surgical excision of the primary lesion appears to be an integral part of systemic therapy for metastatic RCC.

T2 CLEAR CELL RENAL CELL CARCINOMA IS A RARE ENTITY: A STUDY OF 120 CLEAR CELL RENAL CELL CARCINOMAS

PURPOSE

In 2002 the American Joint Committee on Cancer revised the TNM staging system, introducing subclassification for T1 tumors, and invasion of renal sinus fat and sinus veins in categories T3a and T3b, respectively. Since renal sinus invasion represents the most common site of extrarenal extension, the relationship between size, and renal sinus invasion and its effect on the T classification was examined in prospective fashion.

MATERIALS AND METHODS

A total of 175 renal cell carcinomas were examined in prospective fashion with careful evaluation for renal sinus invasion. A minimum of 5 blocks of the renal sinus-tumor interface were examined. Tumors were staged using the 2002 TNM formulation.

RESULTS

The distribution of tumors types was clear cell renal cell carcinoma (CC) in 120 cases, papillary renal cell carcinoma in 30, chromophobe renal cell carcinoma in 12 and miscellaneous other carcinomas in 13. T classifications correlated with tumor type. Only 3 of 30 papillary renal cell carcinomas (10%) and 2 of 9 chromophobe renal cell carcinomas (16.6%) demonstrated extrarenal extension compared with 59 of 120 CCs (49%) (p <0.01). Renal sinus invasion occurred more often than capsule invasion (49% vs 20%, p <0.01). No tumor invaded the capsule that did not also invade the sinus. Compared with 1.1 to 4 cm CCs, of which 85% were renal limited, only 32% of CCs that were 4.1 to 7 cm (p <0.01) and 3% of those larger than 7 cm were renal limited, that is T1b and T2, respectively.

CONCLUSIONS

The incidence of renal sinus invasion increases sharply after tumors exceed 4 cm. T1b CC is uncommon and T2 CC is rare if careful evaluation for sinus invasion is performed.

Histological Subtyping and Nuclear Grading of Renal Cell Carcinoma and Their Implications for Survival: A Retrospective Nation-Wide Study of 629 Patients

OBJECTS

The aim of this study was to evaluate the prognostic significance of the current WHO histological subtyping and Fuhrman nuclear grading on the survival of patients with renal cell carcinoma (RCC).

MATERIALS AND METHODS

A retrospective population-based study was carried out on all patients with a histopathologically confirmed diagnosis of RCC in Iceland between 1971 and 2000. Fuhrman grade, TNM stage, and survival were evaluated and multivariate analysis applied in order to determine prognostic factors.

RESULTS

Out of 629 patients (387 males, 242 females, mean age 64 years), 558 (88.7%) had clear cell, 53 (8.4%) papillary, and 13 (2.1%) chromophobe RCC. Patient demographics were comparable for the two major subtypes, but chromophobe RCCs were larger in size and were diagnosed at a younger age. Clear cell RCCs were more often of higher grades (G3+G4, 48.4%) and at advanced TNM stages (III+IV, 59.3%) than papillary RCCs (22.6% and 34% respectively, p<0.001). Linear regression analysis showed a strong correlation between grade, tumor size, and stage (p<0.001). Chromophobe RCCs had a better survival in univariate analysis than both papillary and clear cell RCCs (84.6% vs. 66.5% and 54.9% 5-year disease specific survival, p<0.001). However, in the multivariate analysis, only the patient's age, calendar year of diagnosis, TNM stage, and nuclear grade were independent prognostic factors of survival.

CONCLUSION

In this complete nation-wide series nuclear grading is important in predicting survival of patients with RCC. It is strongly related to both tumor size and stage, with stage being by far the strongest prognostic factor. Different histological subtypes confer different survival. However, in spite of the distinctive cytogenetic and molecular characteristics of the subtypes, the survival difference is to a large extent due to differences in grade and particularly stage.

Identification of tumor entities of renal cell carcinoma using interphase fluorescence in situ hybridization

PURPOSE

We developed a rapid interphase fluorescence in situ hybridization (FISH) test to differentiate renal cell carcinoma (RCC) based on known genetic alterations and verified the suitability of this test for practical use.

MATERIALS AND METHODS

We composed 2 FISH test sets using 6 centromere specific and 2 region specific DNA probes of human chromosomes. Test set 1 contained centromeric probes for chromosomes 1, 2, 6 and 9, as labeled by 4 fluorescence dyes. For test set 2 we chose 3p24pter and 3p13p14 regions, and centromeric probes of chromosomes 7 and 17. Interphase nuclei of tumor specimens were prepared from 50 mum frozen tissue sections and fixed on slides. The 2 sets were hybridized simultaneously side by side on the same slide.

RESULTS

Seven clear cell carcinomas, 8 papillary carcinomas, 7 chromophobe RCCs and 3 oncocytomas were analyzed by interphase FISH. Results were compared with comparative genomic hybridization findings and pathological reports. Genetic alterations were detected in 22 of 25 analyzed tumors by FISH. FISH findings absolutely correlated with comparative genomic hybridization results. Of the analyzed carcinomas 22 could be identified correctly. In 3 tumors the histological subtypes were revised.

CONCLUSIONS

The results of this study demonstrate that the performed test set allows the accurate identification of RCC in 1 hybridization step. Therefore, FISH represents an effective method for the rapid classification of RCC.

Predicting outcomes in renal cell carcinoma

PURPOSE OF REVIEW

Renal cell carcinoma is estimated to account for more than 35,000 new diagnoses and more than 12,000 cancer-related deaths in the United States in 2005, making it the most lethal of genitourinary malignancies. Approximately 25% of patients with renal cell carcinoma present with metastases, and about a third of those treated surgically for localized renal cell carcinoma will develop a recurrence. Current therapeutic options for disseminated disease benefit only a small percentage of patients.

RECENT FINDINGS

Many clinical, histologic, and molecular factors have been identified that place a patient at risk for recurrence. Several prognostic algorithms, or nomograms, for renal cell carcinoma survival or recurrence after nephrectomy have been developed that incorporate many of these factors.

SUMMARY

Renal cell carcinoma nomograms allow more accurate counseling of patients regarding their probable clinical course, facilitate treatment planning, and identify high-risk patients for experimental treatments.

Can renal oncocytoma be differentiated from its renal mimics? The utility of anti-mitochondrial, caveolin 1, CD63 and cytokeratin 14 antibodies in the differential diagnosis

Among the epithelial renal tumours with eosinophilic cytoplasm, the main differential diagnostic problem arises between renal oncocytomas (ROs) and eosinophilic variants of chromophobe renal cell carcinomas (RCCs). We investigated the possible role of anti-mitochondrial (AMA), anti-caveolin 1 (CAV1), anti-CD63 (CD63) and anti-cytokeratin 14 (CK14) antibodies in the differential diagnosis of eosinophilic epithelial tumours and applied the Muller and Mowry modification of Hale's colloidal iron stain (HCI). Thirty-five ROs and 77 eosinophilic RCCs (27 chromophobe, 28 clear cell and 22 papillary RCCs) were included in this study. Apical and/or polar CD63 immunostaining (94%) and diffuse AMA (91%) and CAV1 (88%) immunostainings were the characteristics of ROs, whereas diffuse CD63 immunostaining (96%) and diffuse-peripheral AMA (96%) and CAV1 (92%) immunostainings were characteristic immunohistochemical features of eosinophilic chromophobe RCCs. We showed CK14 antibody not to be useful in the differential diagnosis of the eosinophilic epithelial renal tumours. The staining localisations with AMA, CAV1 and CD63 antibodies were significantly different between tumour groups. AMA had 96% sensitivity and 94% specificity, whereas CAV1 had 92% sensitivity and 97% specificity in diagnosing chromophobe RCCs. With HCI staining, ROs, showing apical and/or polar staining, could be differentiated from chromophobe RCCs, showing diffuse cytoplasmic staining. HCI had fairly low (69%) sensitivity and 100% specificity, whereas CD63 had 95% sensitivity and 100% specificity to diagnose ROs. We recommend using CD63 as the best marker of choice for distinguishing ROs from eosinophilic chromophobe RCCs when standard diagnostic criteria are not helpful.

Histologic coagulative tumor necrosis as a prognostic indicator of renal cell carcinoma aggressiveness

BACKGROUND

Prognostic markers for renal cell carcinoma (RCC), such as patient symptoms, tumor stage, tumor size, and tumor grade, are useful for determining appropriate follow-up and selecting patients for adjuvant therapy. Histologic coagulative tumor necrosis, also reported to be a prognostic marker for RCC, has not previously been extensively described or investigated. Hence, the objective of the current study was to characterize tumor necrosis as a prognostic feature of RCC.

METHODS

The authors of the current study identified 3009 patients treated surgically for RCC between 1970 and 2002 from the Mayo Clinic Nephrectomy Registry (Rochester, MN). Associations of tumor necrosis with clinical, laboratory, and pathologic features were examined with chi-square, Fisher exact test, and Wilcoxon rank-sum tests. Cancer-specific survival was estimated with the Kaplan-Meier method, and associations with outcome were assessed with Cox proportional hazard models.

RESULTS

Tumor necrosis was present in 690 of 2445 (28%) clear cell, 196 of 421 (47%) papillary, and 28 of 143 (20%) chromophobe RCCs. The risk ratio for death from RCC in patients with necrotic compared with non-necrotic tumors was 5.27 (95% confidence interval [CI]: 4.56-6.09; P < 0.001) for clear cell, 4.20 (CI: 1.65-10.68; P < 0.001) for chromophobe, and 1.49 (CI: 0.81-2.74; P = 0.199) for papillary RCC. The survival difference for clear cell RCC persisted even after multivariate adjustment for tumor stage, size, and grade (risk ratio 1.90; P < 0.001).

CONCLUSIONS

Histologic coagulative tumor necrosis is an independent predictor of outcome for clear cell and chromophobe RCC, and it should be routinely reported and used in clinical assessment.

Distribution of cytokeratins and vimentin in adult renal neoplasms and normal renal tissue: potential utility of a cytokeratin antibody panel in the differential diagnosis of renal tumors

Adult renal epithelial neoplasms (RENs) comprise several distinct clinicopathologic entities with potential prognostic and therapeutic differences. Individual cases can show overlapping morphologic features, necessitating the use of ancillary methods. The purpose of this study was to determine the diagnostic utility of cytokeratin (CK) subtype expression pattern in a wide range of adult RENs. RENs (including clear cell [conventional] renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, renal oncocytoma, collecting duct carcinoma (CDC), renal medullary carcinoma (RMC), urothelial carcinoma, metanephric adenoma (MA), tubulocystic carcinoma (TC) (also known as low-grade collecting duct carcinoma), and mucinous tubular and spindle cell carcinoma) were immunostained for CK subtypes (CK5/CK6, 7, 8, 13, 14, 17, 18, 19, 20), high molecular weight CKs 1, 5, 10, 14 (HMWCK), and vimentin (Vim). The expression pattern of normal kidney was also examined and correlated with RENs. Although there is some overlap, subtypes of RENs show distinctive CK expression profiles that may be useful in several differential diagnostic settings. Clear cell RCCs typically showed a restricted expression pattern of CK8, CK18 and Vim. Papillary RCCs typically expressed CK7, CK8, CK18, CK19, and Vim and could be distinguished from MA (CK7-). Chromophobe RCCs were typically CK7+, CK8+, CK18+, and Vim-, and could be distinguished from oncocytomas (typically CK7-). In oncocytomas, nonspecific staining of unblocked endogenous biotin is a potentially significant diagnostic pitfall. CDC, RMC, and TC demonstrated similar CK expression profiles (with the exception of HMWCK expression limited to CDC), supporting a close relationship between these entities. A panel of CK5/CK6, CK17, and Vim may be helpful in distinguishing CDC (typically CK5/CK6-, CK17-, Vim+) and urothelial carcinoma (typically CK5/CK6+, CK17+, Vim-). In conclusion, CK expression patterns may be helpful in several differential diagnostic situations when dealing with adult RENs.

A Molecular Classification of Papillary Renal Cell Carcinoma

Despite the moderate incidence of papillary renal cell carcinoma (PRCC), there is a disproportionately limited understanding of its underlying genetic programs. There is no effective therapy for metastatic PRCC, and patients are often excluded from kidney cancer trials. A morphologic classification of PRCC into type 1 and 2 tumors has been recently proposed, but its biological relevance remains uncertain. We studied the gene expression profiles of 34 cases of PRCC using Affymetrix HGU133 Plus 2.0 arrays (54,675 probe sets) using both unsupervised and supervised analyses. Comparative genomic microarray analysis was used to infer cytogenetic aberrations, and pathways were ranked with a curated database. Expression of selected genes was validated by immunohistochemistry in 34 samples with 15 independent tumors. We identified two highly distinct molecular PRCC subclasses with morphologic correlation. The first class, with excellent survival, corresponded to three histologic subtypes: type 1, low-grade type 2, and mixed type 1/low-grade type 2 tumors. The second class, with poor survival, corresponded to high-grade type 2 tumors (n = 11). Dysregulation of G1-S and G2-M checkpoint genes were found in class 1 and 2 tumors, respectively, alongside characteristic chromosomal aberrations. We identified a seven-transcript predictor that classified samples on cross-validation with 97% accuracy. Immunohistochemistry confirmed high expression of cytokeratin 7 in class 1 tumors and of topoisomerase IIalpha in class 2 tumors. We report two molecular subclasses of PRCC, which are biologically and clinically distinct and may be readily distinguished in a clinical setting.

Oncocytic renal neoplasms: diagnostic considerations

Advances in our understanding of renal neoplasia have resulted in recognition of numerous tumors that are composed predominantly of cells with abundant eosinophilic cytoplasm. This article discusses the features of renal oncocytoma (including oncocytosis), chromophobe renal cell carcinoma (RCC), and clear cell RCC; explores the relationship between renal oncocytoma and chromophobe RCC; briefly discusses other tumors with abundant eosinophilic cytoplasm; and emphasizes the differential diagnosis of such tumors.

Clear cell renal cell carcinoma

Clear cell RCC is the most common type of RCC that occurs in adults. It has the worst prognosis among the common epithelial tumors of the kidney. Histologically, a wide range of morphologic patterns can be encountered. Those cases with a multi-locular cystic architecture are considered to be a distinct subtype because of the clinicopathologic features.

Independent validation of the 2002 American Joint Committee on cancer primary tumor classification for renal cell carcinoma using a large, single institution cohort

PURPOSE

The primary tumor classification for renal cell carcinoma (RCC) was updated by the American Joint Committee on Cancer in 2002. To date the new classification has not been validated using an independent group of patients and, therefore, its accuracy for predicting patient outcome is unknown. In the current study we evaluated the 2002 primary tumor classification and compared its predictive ability with that of the 1997 classification.

MATERIALS AND METHODS

We studied 2,746 patients treated with radical nephrectomy or nephron sparing surgery for unilateral, sporadic RCC between 1970 and 2000. Cancer specific survival was estimated using the Kaplan-Meier method. The predictive abilities of the 1997 and 2002 classifications were compared using the concordance index.

RESULTS

There were 812 deaths from RCC a mean of 3.3 years following nephrectomy. Median followup in patients still alive at last followup was 9 years. Estimated 5-year cancer specific survival rates by the 2002 tumor classification were 97%, 87%, 71%, 53%, 44%, 37% and 20% in patients with pT1a, pT1b, pT2, pT3a, pT3b, pT3c and pT4 RCC, respectively. The concordance index for the association between the 2002 classification and death from RCC was 0.752 compared with 0.737 for the 1997 classification, indicating that the 2002 version contained more predictive ability.

CONCLUSIONS

Our data suggest that the 2002 primary tumor classification with pT1 cancers subclassified into pT1a and pT1b provides excellent stratification of patients according to cancer specific survival and it has a predictive ability that is superior to that of the 1997 classification.

Renal cell carcinoma 2005: new frontiers in staging, prognostication and targeted molecular therapy

PURPOSE

Renal cell carcinoma (RCC) has traditionally been staged using a purely anatomical staging system. Although current staging systems provide good prognostic information, data published in the last few years has led to significant controversies as to whether further revisions are needed and whether improvements can be made with the introduction of new, more accurate and predictive prognostic factors not currently included in traditional staging systems. This review highlights such controversies and provides an update on current staging modalities, prognostic factors and targeted molecular therapy for RCC.

MATERIALS AND METHODS

A comprehensive review of the peer reviewed literature was performed on the topic of current staging modalities, validated prognostic factors, predictive nomograms, molecular markers and targeted molecular therapy for RCC.

RESULTS

A staging system for malignant disease such as RCC uses various characteristics of tumors to stratify patients into clinically meaningful categories, which can be used to provide patients with counseling regarding prognosis, select treatment modalities and determine eligibility for clinical trials. The TNM staging system is currently the most extensively used one. However, it has undergone recent systematic revision due to rapidly emerging data from longer patient followup. The identification of various histological and symptomatic factors has led groups at many centers to develop more comprehensive staging systems that integrate these factors and include patients with metastatic and local disease. While integrated staging systems have improved RCC staging, the recent discovery of molecular tumor markers is expected to revolutionize RCC staging in the future and lead to the development of new therapies based on molecular targeting.

CONCLUSIONS

Staging systems for RCC serve as a valuable prognostic tool. Several new patient and tumor characteristics have been reported to be important prognostic factors and they have been integrated into current staging systems. In addition, the field of RCC is rapidly undergoing a revolution led by molecular markers and targeted therapies. With this information urologists will be updated with the most current and comprehensive staging strategies, and be provided with a glimpse of the molecular and patient specific staging and treatment paradigms that will in our opinion transform the future management of this malignancy.

Loss of expression of von Hippel-Lindau tumor suppressor protein associated with improved survival in patients with early-stage clear cell renal cell carcinoma

OBJECTIVES

To determine whether actual expression of the von Hippel-Lindau (VHL) protein product itself (pVHL) is associated with clear cell renal cell carcinoma (CC-RCC) survival. Recent data have suggested that somatic mutations of the VHL tumor suppressor gene are associated with better cancer-specific survival in patients with CC-RCC.

METHODS

Using a large, clinic-based cohort of 273 patients with CC-RCC, we tested the hypothesis that those patients with CC-RCC tumors lacking pVHL expression [pVHL(-)] will experience better cancer-specific survival than those patients with tumors that show pVHL expression [pVHL(+)].

RESULTS

Using a Cox proportional hazard model adjusting for age, patients with pVHL(-) tumors were not at a decreased risk of CC-RCC death compared with patients with pVHL(+) tumors (hazard ratio 1.0, 95% confidence interval 0.7 to 1.5). Adjustment for the Mayo SSIGN score had little effect on the risk estimate (hazard ratio 0.8; 95% confidence interval 0.5 to 1.2). In our stratified analysis, we found evidence of an inverse association with loss of pVHL expression among those patients presenting with early-stage disease (hazard ratio 0.4; 95% confidence interval 0.2 to 0.8), even after adjustment for the Mayo SSIGN score.

CONCLUSIONS

Although we report no overall association, the data from this investigation are consistent with earlier findings that suggest somatic VHL alteration is associated with better cancer-specific survival among those patients presenting with early-stage (pT1 and pT2) CC-RCC.

A Review of Prognostic Pathologic Features and Algorithms for Patients Treated Surgically for Renal Cell Carcinoma

Accurate subtyping of RCC is critically important and should be considered in algorithms that are developed as prognostic tools for the patient and clinician. The TNM classification, already a powerful prognostic factor, will continue to evolve. The authors recommend that each component of the classification be assessed and reported during pathologic examination. This article also highlighted the importance of assigning a nuclear grade that is based on standardized and reproducible criteria that reflect the heterogeneity of nuclear and nucleolar features within RCC. Lastly, it is increasingly evident that coagulative tumor necrosis and sarcomatoid differentiation are compelling prognostic factors, on par with nuclear grade, and should be assessed routinely. To conclude, the complete list of pathologic features that are evaluated as part of the Mayo Clinic Nephrectomy Registry is presented. The features that are reported routinely in clinical practice also are indicated; this can serve as a guide for the reporting of results from the pathologic examination of RCC.

Prognostic value of histologic subtypes in renal cell carcinoma: a multicenter experience

PURPOSE

To analyze to what extent histologic subtype is of prognostic importance in renal cell carcinoma based on a large, international, multicenter experience.

PATIENTS AND METHODS

Four thousand sixty-three patients from eight international centers were included in this retrospective study. Histologic subtype (1997 International Union Against Cancer [UICC] criteria of tumor response), age, sex, TNM stage, Fuhrman grade, tumor size, Eastern Cooperative Oncology Goup performance status (ECOG PS), and overall survival were determined in all cases. The prognostic values of clear cell, papillary, and chromophobe histologic features were assessed by uni- and multivariate analysis using the Kaplan-Meier method and Cox model, respectively.

RESULTS

Clear cell, papillary, and chromophobe carcinomas accounted for 3,564 (87.7%), 396 (9.7%) and 103 (2.5%) cases, respectively. In univariate analysis, a trend toward a better survival was observed when clear cell, papillary, and chromophobe histologies were considered prognostic categories (log-rank P = .0007). However, in multivariate analysis, TNM stage, Fuhrman grade and ECOG PS, but not histology, were retained as independent prognostic variables (P < .001).

CONCLUSION

The stratification in three main renal cell carcinoma histologic subtypes as defined by the 1997 UICC-American Joint Committee on Cancer consensus should not be considered a major prognostic variable comparable to TNM stage, Fuhrman grade and ECOG PS.

Tumor classification by tissue microarray profiling: random forest clustering applied to renal cell carcinoma

We describe a novel strategy (random forest clustering) for tumor profiling based on tissue microarray data. Random forest clustering is attractive for tissue microarray and other immunohistochemistry data since it handles highly skewed tumor marker expressions well and weighs the contribution of each marker according to its relatedness with other tumor markers. This is the first tumor class discovery analysis of renal cell carcinoma patients based on protein expression profiles. The tissue array data contained at least three tumor samples from each of 366 renal cell carcinoma patients. The eight tumor markers explore tumor proliferation, cell cycle abnormalities, cell mobility, and the hypoxia pathway. Since the procedure is unsupervised, no clinicopathological data or traditional classifications are used a priori. To explore whether the tissue microarray data can be used to identify fundamental subtypes of renal cell carcinoma patients, we first carried out random forest clustering of all 366 patients. By analyzing the tumor markers simultaneously, the procedure automatically detected classes that correspond to clear- vs non-clear cell tumors (demonstration of proof-of-principle). The resulting molecular grouping provides better prediction of survival (logrank P=0.000090) than this classical pathological grouping (logrank P=0.023). We then sought to extend the class discovery by searching for finer subclasses of clear cell patients. The procedure automatically discovered: (a) two classes corresponding to low- and high-grade patients (demonstration of proof-of-principle); (b) a subgroup of long-surviving clear cell patients with a distinct molecular profile and (c) two novel tumor subclasses in low-grade clear cell patients that could not be explained by any clinicopathological variables (demonstration of discovery).

S100A1 and KIT gene expressions in common subtypes of renal tumours

AIM

The aim of this study is to evaluate the S100A1 and KIT as gene markers for the differentiation of common subtypes of renal tumours.

METHODS

Fifty-five tissue samples (15 clear cell RCCs, 15 papillary RCCs, 7 chromophobe RCCs, 8 oncocytomas and 10 normal renal tissues) were studied The gene expressions of S100A1 and KIT were analysed by one-step RT-PCR by using the specific primers.

RESULTS

S100A1 was expressed in 2/15 clear cell RCCs, 11/15 papillary RCCs, 7/8 oncocytomas and in 0/7 chromophobe RCCs. KIT gene was expressed in 6/7 chromophobe RCCs and 7/8 oncocytomas while 0/15 clear cell RCCs and 1/15 papillary RCCs expressed kit gene. Normal tissue expressed neither S100A1 nor KIT gene.

CONCLUSION

S100A1 and KIT can be used as gene markers for the differentiation of common subtypes of renal tumours.

Kit (CD117) immunoreactivity is rare in renal cell and upper urinary tract transitional cell carcinomas

OBJECTIVE

To investigate the presence of Kit (CD117), a transmembrane tyrosinase-kinase receptor, in primary and metastatic renal cell carcinomas (RCCs) and upper urinary tract transitional cell carcinomas (TCCs).

MATERIALS AND METHODS

In human neoplasia, overexpression of Kit has been related to cell proliferation, differentiation, adhesion and control of apoptosis. If present, Kit may provide a suitable target for tumour therapy. Formalin-fixed and paraffin-embedded specimens of 180 primary and 58 metastatic RCCs and 54 upper urinary tract TCCs were immunostained for Kit (CD117) using a tissue microarray technique.

RESULTS

In RCCs, immunoreactivity for CD117 was detected in only two of 23 (9%) chromophobe tumours, whereas all 137 conventional and 20 papillary subtypes, and metastatic RCC tissues, lacked CD117 immunoreactivity. In TCCs, CD117 expression of <10% cancer cells was found in two of 53 (4%) cases. Stromal mast cells served as a positive control and showed specific immunostaining.

CONCLUSION

Kit immunoreactivity is infrequent in both RCCs and upper urinary tract TCCs. Thus, routine screening of tumour tissues for Kit by immunohistochemistry appears to be cost-ineffective and cannot be recommended. Moreover, the lack of substantial Kit immunoreactivity in both primary and metastatic carcinomas does not provide a rationale to investigate imatinib mesylate therapy in clinical trials including patients with advanced disease.

The diagnostic utility of MOC31, BerEP4, RCC marker and CD10 in the classification of renal cell carcinoma and renal oncocytoma: an immunohistochemical analysis of 328 cases

AIMS

To demonstrate the diagnostic utility of MOC31, BerEP4, renal cell carcinoma marker (RCC Ma) and CD10 in the classification of RCC and renal oncocytoma, based upon a comprehensive immunohistochemical analysis.

METHODS AND RESULTS

Immunohistochemistry was performed on 328 samples consisting of 256 clear cell/conventional, 27 papillary, 28 chromophobe, five collecting duct, five unclassified RCCs and seven renal oncocytomas using antibodies MOC31, BerEP4 and antibodies against cytokeratins (KL-1, CAM5.2, 34betaE12, cytokeratin 7), RCC Ma, epithelial membrane antigen, E-cadherin, CD10, CD15 and vimentin. Multivariate analysis showed that MOC31, BerEP4, RCC Ma and CD10 have discriminatory value. MOC31 and BerEP4 chiefly labelled distal tubules of normal kidney while RCC Ma and CD10 labelled the proximal tubules. Twenty-three chromophobe RCCs (82%) were reactive for MOC31, while only four clear cell RCCs and three papillary RCCs were positive for this marker. Clear cell RCCs were characterized by a high positive rate for CD10 (82%) and a low positive rate for BerEP4 (27%). Papillary RCCs frequently coexpressed RCC Ma and BerEP4 (51%). All renal oncocytomas were negative for MOC31 and CD10.

CONCLUSIONS

MOC31 has diagnostic merit in discerning chromophobe RCC. The CD10+/BerEP4- profile and RCC Ma+/BerEP4+ profile achieve moderate sensitivity and good specificity for clear cell RCC and papillary RCC, respectively. The non-reactivity for both MOC31 and CD10 is helpful in distinguishing renal oncocytoma from RCC. When properly selected, antibodies have immunohistochemical diagnostic utility for the classification of renal cortical epithelial tumours.

CANCER SPECIFIC SURVIVAL FOR PATIENTS WITH pT3 RENAL CELL CARCINOMA—CAN THE 2002 PRIMARY TUMOR CLASSIFICATION BE IMPROVED?

PURPOSE

The 2002 primary tumor classification for renal cell carcinoma (RCC) does not distinguish between patients with tumor thrombus involving the renal vein only and those with inferior vena cava tumor thrombus below the diaphragm. We evaluated the association of tumor thrombus level and fat invasion with outcome to determine if further subclassification would improve the prognostic accuracy of the current classification.

MATERIALS AND METHODS

We studied 675 patients treated with radical nephrectomy or nephron sparing surgery for pT3a (206, 30.5%), pT3b (422, 62.5%), pT3c (19, 2.8%) or pT4 (28, 4.2%) RCC at the Mayo Clinic between 1970 and 2000. Associations with outcome were evaluated using Cox proportional hazards regression.

RESULTS

There were 531 deaths from RCC at a median of 1.5 years following nephrectomy. Patients with pT3b RCC and level I, II or III tumor thrombus were significantly more likely to die of RCC compared to patients with pT3b RCC and level 0 tumor thrombus (risk ratio 1.62, p <0.001). Patients with peripheral perinephric or renal sinus fat invasion were also more likely to die of RCC compared to patients without fat invasion (risk ratio 1.87, p <0.001). Therefore, patients with pT3 RCC were reclassified into 4 groups as thrombus level 0 without fat invasion, fat invasion only, thrombus level 0 with fat invasion or thrombus level I, II or III without fat invasion, and thrombus level I, II or III with fat invasion or thrombus level IV. This reclassification significantly improved prediction of death from RCC compared with the current classification (c indexes of 0.61 versus 0.55, respectively).

CONCLUSIONS

Further subclassification of the primary tumor classification for patients with pT3 RCC improved prognostic accuracy.

Workshop on Cancer Biometrics: Identifying Biomarkers and Surrogates of Cancer in Patients

The current excitement about molecular targeted therapies has driven much of the recent dialog in cancer diagnosis and treatment. Particularly in the biologic therapy of cancer, identifiable antigenic T-cell targets restricted by MHC molecules and the related novel stress molecules such as MICA/B and Letal allow a degree of precision previously unknown in cancer therapy. We have previously held workshops on immunologic monitoring and angiogenesis monitoring. This workshop was designed to discuss the state of the art in identification of biomarkers and surrogates of tumor in patients with cancer, with particular emphasis on assays within the blood and tumor. We distinguish this from immunologic monitoring in the sense that it is primarily a measure of the tumor burden as opposed to the immune response to it. Recommendations for intensive investigation and targeted funding to enable such strategies were developed in seven areas: genomic analysis; detection of molecular markers in peripheral blood and lymph node by tumor capture and RT-PCR; serum, plasma, and tumor proteomics; immune polymorphisms; high content screening using flow and imaging cytometry; immunohistochemistry and tissue microarrays; and assessment of immune infiltrate and necrosis in tumors. Concrete recommendations for current application and enabling further development in cancer biometrics are summarized. This will allow a more informed, rapid, and accurate assessment of novel cancer therapies.

Prognostic relevance of extensive necrosis in renal cell carcinoma

AIMS

Evidence suggests that the presence of tumour necrosis is an adverse prognostic factor in renal cell carcinoma (RCC). However, it has also been shown that tumour regression, a microscopic feature associated with necrosis, may be a favourable short term prognostic factor in RCC.

METHODS

Pathology reports of 253 RCCs from 1992 to 2001 were reviewed, and identified 37 tumours with substantial macroscopic or microscopic necrosis. Microscopic pathology, TNM 1997 tumour stage, and clinical follow up were reviewed and correlated with pathological findings. Three cases were rejected because two were diagnosed at necropsy, and a third was the result of renal arterial embolisation.

RESULTS

Twenty of the 34 cases showed <50% necrosis, 10 showed 50-94% tumour necrosis, and four showed >95% tumour necrosis. Follow up data were unavailable in three cases. Nine of the remaining 31 tumours progressed; six were group 3 tumours showing <50% necrosis, three were group 2 tumours showing 50-94% necrosis, and none was a group 1 tumour showing >95% necrosis.

CONCLUSIONS

Extensive necrosis (>95% necrosis) is rare in RCC, accounting for only 1.6% of those diagnosed during eight years in this unselected hospital series. The microscopic pattern of necrosis was typical, requiring extensive tumour sampling for definitive tumour diagnosis. Although there were only four patients with extensive necrosis, none developed recurrent or metastatic carcinoma, or died from RCC. Although extensive (>95%) necrosis may imply better short term prognosis after adjusting for tumour pathological TNM stage, it is probably not a prognostic variable in RCC.

Renal cell carcinoma in South Korea: a multicenter study

The incidence of renal cell carcinoma (RCC) in South Korea is steadily becoming similar to that in Western countries. This study summarizes the results of a 3-year multicenter survey of RCC in South Korea, conducted by the Korean Genitourinary Pathology Study Group. A total of 795 cases of RCC were collected from 20 institutes between 1995 and 1997, including 686 clear cell RCCs (86.3%), 58 papillary RCCS (7.30%), 49 chromphobe RCCs (6.16%), and 2 collecting duct RCCs (0.25%). At least 5 years of follow-up was available for 627 clear cell, 54 papillary, and 49 chromophobe RCCs. All subtypes presented most frequently with stage T3aN0M0 at the time of operation, and papillary RCCs demonstrated more frequent lymph node metastasis. Overall survival was not significantly related to the histological subtype (clear cell vs papillary, P = 0.8651; clear cell vs chromophobe, P = 0.0584; papillary vs chromophobe, P = 0.0743). For clear cell RCCs, statistically significant associations were found between overall survival and sex (P = 0.0153), multiplicity (P = 0.0461), necrosis (P = 0.0191), age, sarcomatoid change, TNM stage, nuclear grade, and modality of treatment (all P <0.0001). Overall survival was significantly associated with tumor size (P = 0.0307), nuclear grade (P = 0.0235), multiplicity, sarcomatoid change, and TNM stage (all P <0.0001) for papillary RCCs and with the presence of sarcomatoid change (P = 0.0281), nuclear grade (P = 0.0015), treatment modality (P = 0.0328), and TNM stage (P <0.0001) for chromophobe RCCs. Age (P = 0.0125), nodal stage (P = 0.0010), and treatment modality (P = 0.0001) were significant independent prognostic indicators for clear cell RCC on multivariate analysis. This is the first multicenter study of RCC in South Korea, demonstrating the general patterns and prognostic factors of Korean RCCs.

pT2 CLASSIFICATION FOR RENAL CELL CARCINOMA. CAN ITS ACCURACY BE IMPROVED?

PURPOSE

The 2002 tumor classification for renal cell carcinoma (RCC) classifies pT2 tumors as more than 7 cm in greatest dimension, limited to the kidney. In this study we determined whether a size cutoff point exists within pT2 tumors and whether such subclassification would further improve the accuracy of the current tumor classification.

MATERIALS AND METHODS

We studied 544 patients with unilateral, sporadic pT2 RCC treated with radical nephrectomy or nephron sparing surgery between 1970 and 2000. The association of tumor size with death from RCC was examined using martingale residuals from a Cox proportional hazards regression model to determine the optimal size cutoff point.

RESULTS

There were 204 deaths from RCC a median of 3.8 years following nephrectomy. Univariately tumor size was significantly associated with death from RCC (risk ratio 1.08, 95% CI 1.04 to 1.13, p <0.001). A scatterplot of tumor size vs expected risk of death per patient suggested that a cutoff point between 9 and 10 cm was appropriate. When adjusted for regional lymph node involvement and distant metastases, the 10 cm cutoff point performed better than the 9 cm point (risk ratio 1.42, 95% CI 1.07 to 1.90, p = 0.017 vs 1.22, 95% 0.86 to 1.72, p = 0.268). Therefore, we propose using a 10 cm cutoff point to subclassify patients into pT2a and pT2b.

CONCLUSIONS

Our data suggest that the prognostic accuracy of the 2002 pT2 tumor classification can be further improved by subclassifying patients with tumors greater than 7 and less than 10 cm into a pT2a category, and those with tumors 10 cm or greater into a pT2b category.

Immunohistochemical expression of 14-3-3 sigma protein in human urological and gynecological tumors using a multi-tumor microarray analysis

14-3-3 sigma is an exclusive epithelial marker and data on its expression in different malignancies are very scarce. The aims of the present study are to screen its expression in the most common neoplasms occurring in the urological and gynecological tract and to evaluate its use as a diagnostic marker. A tissue microarray was constructed using 350 samples from 13 different neoplasms. Immunohistochemical analysis using a polyclonal 14-3-3 sigma antibody was performed. Overall, this protein was positive in 141 and negative in 209 tumors. The most frequent expression was seen in squamous cell carcinoma of the cervix and urothelial bladder carcinoma, followed by prostatic and endometrial adenocarcinoma. 14-3-3 sigma was able to distinguish prostate adenocarcinoma from urothelial bladder carcinoma, with an odds ratio of 0.028 (P = 0.001; 95% CI, 0.0003-0.222), and distinguish seminoma from embryonal carcinoma of the testis, with an odds ratio of 0.061 (P = 0.009; 95% CI, 0.007-0.5014). It also has a good value in differentiating renal clear cell carcinoma from papillary carcinoma, with an odds ratio 0.470 (P < 0.001; 95% CI, 0.008-0.261). 14-3-3 sigma seems to have good potential use as an epithelial marker, after confirmation with further targeted studies. Finally, as with all immunohistochemical markers, we can optimize the utility of this protein to distinguish tumor mimics by including it in an appropriate immunohistochemical panel.

Neuropeptide Y receptors in renal cell carcinomas and nephroblastomas

Numerous peptide receptors are overexpressed in human cancer, permitting in vivo tumor targeting. Among such receptors, those for the neurotransmitter neuropeptide Y (NPY) are overexpressed in various tumors. Since NPY can play a role in the kidney, NPY receptor expression and/or endogenous production of peptides of the NPY family (NPY, PYY, PP) were evaluated in 40 renal cell carcinomas (RCCs) and 18 nephroblastomas. NPY receptor protein expression was investigated by in vitro autoradiography using (125)I-labeled PYY in competition with NPY receptor subtype-selective analogs. NPY, PYY and PP production was assessed immunohistochemically. Fifty-six percent of RCCs expressed the Y1 receptor subtype in moderate density, and 80% of nephroblastomas expressed Y1 and Y2 subtypes in moderate to high density. Y1 was also highly expressed in intratumoral blood vessels. In selected cases, NPY was observed in nerve fibers in close association with intratumoral blood vessels and in the vicinity of tumor cells, while no PYY or PP was detected immunohistochemically in these sites. NPY receptors on renal tumor cells and tumor blood vessels may therefore be the molecular targets of endogenous NPY released by intratumoral nerve fibers. With regard to clinical applications, NPY receptors may act as in vivo targets for receptor-directed therapy of RCCs and nephroblastomas for which alternative therapeutic approaches are still required.

Clinicopathologic and molecular correlations of necrosis in the primary tumor of patients with renal cell carcinoma

BACKGROUND

The presence of histologic necrosis in the primary tumor of patients with renal cell carcinoma (RCC) has been suggested to be an important predictor of survival. The authors investigated the relation of tumor necrosis to other clinicopathologic factors known to be important prognostic indicators for patients with RCC.

METHODS

The records of 311 patients undergoing treatment for RCC were evaluated for basic clinicopathologic information including TNM classification, nuclear grade, Eastern Cooperative Oncology Group (ECOG) performance status (PS), disease recurrence, and survival. The presence and extent of histologic necrosis of the primary tumors was recorded and correlated with clinicopathologic factors, carbonic anhydrase IX and Ki-67 expression, disease recurrence, and survival.

RESULTS

The presence of necrosis in the primary tumor of patients with RCC compared with patients with RCC without necrosis was associated with higher T classification (P < 0.0001), the presence of lymph node disease (P = 0.009), the presence of metastases (P < 0.0001), higher grade (P < 0.0001), greater mean tumor size (P < 0.0001), an ECOG PS score > or = 1 (P = 0.007), higher University of California-Los Angeles Integrated Staging System (UISS) category (P < 0.0001), and higher Ki-67 expression (P < 0.0001). The extent of necrosis in the primary tumor was associated with the presence of lymph node disease (P = 0.009) and the presence of metastases (P < 0.0001), and correlated with higher T classification (sigma = 0.31, P < 0.0001), poorer ECOG PS (sigma = 0.18, P = 0.002), higher grade (sigma = 0.33, P < 0.0001), greater tumor size (sigma = 0.40, P < 0.0001), higher UISS category (sigma = 0.37, P < 0.0001), and higher Ki-67 staining (sigma = 0.32, P < 0.0001). Patients with the presence of necrosis in the primary tumor demonstrated a lower 5-year disease-specific survival compared with patients without necrosis in the primary tumor (36% vs. 75%; P < 0.0001). Multivariate analysis demonstrated that T classification (P < 0.0001), distant metastases (P < 0.0001), and ECOG PS (P < 0.0001) were independent predictors of DSS, whereas the presence of necrosis was not (P = 0.1100). Substratification into localized and metastatic disease demonstrated that the presence of necrosis was an independent predictor of survival in patients with localized (P = 0.025), but not metastatic (P = 0.44), disease. The extent of necrosis was not an independent predictor of survival (P > 0.05). Patients with the presence of necrosis in the primary tumor had a lower 5-year disease recurrence-free rate compared with patients without the presence of necrosis (62% vs. 92%, P < 0.0001).

CONCLUSIONS

The presence of necrosis in the primary tumor was associated with adverse prognostic factors such as high T classification, presence of lymph node disease and metastases, high grade, large tumor size, and poor ECOG PS. The extent of necrosis was found to be associated with the presence of lymph node disease and metastases and correlated with higher T classification, higher grade, greater tumor size, poorer ECOG PS, and higher UISS category. The presence of this histologic variant was an independent predictor of poor survival in patients with localized, but not metastatic, disease. In addition, Ki-67 expression served as a valuable surrogate marker for the presence of histologic tumor necrosis.

Costimulatory B7-H1 in renal cell carcinoma patients: Indicator of tumor aggressiveness and potential therapeutic target

Expression of B7-H1, a costimulating glycoprotein in the B7 family, is normally restricted to macrophage-lineage cells, providing a potential costimulatory signal source for regulation of T cell activation. In contrast, aberrant expression of B7-H1 by tumor cells has been implicated in impairment of T cell function and survival, resulting in defective host antitumoral immunity. The relationship between tumor-associated B7-H1 and clinical cancer progression is unknown. Herein, we report B7-H1 expression by both renal cell carcinoma (RCC) tumors of the kidney and RCC tumor-infiltrating lymphocytes. In addition, our analysis of 196 clinical specimens reveals that patients harboring high intratumoral expression levels of B7-H1, contributed by tumor cells alone, lymphocytes alone, or tumor and/or lymphocytes combined, exhibit aggressive tumors and are at markedly increased risk of death from RCC. In fact, patients with high tumor and/or lymphocyte B7-H1 levels are 4.5 times more likely to die from their cancer than patients exhibiting low levels of B7-H1 expression (risk ratio 4.53; 95% confidence interval 1.94-10.56; P < 0.001.) Thus, our study suggests a previously undescribed mechanism whereby RCC may impair host immunity to foster tumor progression. B7-H1 may prove useful as a prognostic variable for RCC patients both pre- and posttreatment. In addition, B7-H1 may represent a promising target to facilitate more favorable responses in patients who require immunotherapy for treatment of advanced RCC.

A phase II trial of gefitinib (Iressa, ZD1839) in stage IV and recurrent renal cell carcinoma

PURPOSE

The epidermal growth factor receptor (EGFR) is overexpressed in 75 to 90% of renal cell carcinomas and may play a role in tumor initiation and progression. Gefitinib (Iressa, ZD1839) is a potent, selective EGFR-tyrosine kinase inhibitor. This trial was undertaken to assess the efficacy and toxicity of gefitinib in advanced renal cell carcinoma.

EXPERIMENTAL DESIGN

Oral gefitinib, 500 mg once daily, was given continuously. A single-dose reduction to 250 mg daily was allowed for toxicity. The primary end point was response rate (defined as complete remission + partial remission + stable disease). Secondary end points were progression-free survival, overall survival, toxicity, and correlation of response with EGFR status.

RESULTS

Twenty-one patients were enrolled on this study, and all are evaluable for response and toxicity. Patient characteristics were median age 61 (range, 35-78 years); 17 males, 4 females; median performance status 0 (range 0-2); median number of prior systemic therapies 1 (range, 0-3). The median and mean number of cycles of therapy received was 3 and 4.7 (range, 1-14+). The best response was stable disease in eight patients (38%). Median progression-free survival was 2.7 months. Median overall survival was 8.3 months. The difference in overall survival was significantly different between patients with progressive disease versus stable disease (6.1 months versus 16+ months; Log-Rank test P value < 0.0001). Three patients required a dose reduction, all for grade 3 diarrhea. There was no apparent correlation between EGFR status and stability of disease or progression of disease.

CONCLUSIONS

Gefitinib is without significant conventional activity in renal cell carcinoma. The relation of "stable disease" to treatment or to disease-related prognostic heterogeneity remains to be defined.

The Renal Sinus Is the Principal Invasive Pathway

A total of 100 renal cell carcinomas were prospectively examined for renal sinus invasion, 74 clear cell renal cell carcinomas (CC), 3 renal cell carcinomas, unclassified (RUC), 16 papillary renal cell carcinomas (PapC), and 7 chromophobe renal cell carcinomas (ChC). Using the 2002 TNM staging formulation, 49 tumors were T1, 5 were T2, and 46 were T3 or T4. Renal sinus invasion occurred more often than renal capsule invasion. No tumor invaded the capsule that did not also invade the sinus. Renal sinus invasion correlated with Fuhrman grade; 17% of grades 1/2 tumors invaded the sinus, while 71% of grade 3/4 tumor invaded the sinus (P < 0.001). Sinus invasion correlated with tumor type; 2 of 23 PapC and ChC invaded the sinus compared with 44 of 77 CC and RUC. Sinus invasion occurred in approximately 16% of tumors 1 to 4 cm in size, then abruptly increased for larger tumors (P < 0.001). When tumors are staged by the 1997 and 2002 TNM formulation, renal sinus invasion upstaged 28% of cases stage T1 or T2 by the 1997 formulation, to T3 using the 2002 criteria. In conclusion, renal sinus invasion is the most common site of extrarenal extension of renal carcinoma and correlates with tumor type, grade and size. Appropriate evaluation for sinus invasion reduces the incidence of T1b and T2 CC tumors, limiting prognostic utility and suggesting reassessment of the T1 and T2 stage designations.

CD10 is expressed in a subset of chromophobe renal cell carcinomas

CD10 has been considered a useful marker in the diagnosis of renal carcinomas, because of its expression in clear cell and papillary renal cell carcinomas and its absence in chromophobe renal cell carcinomas. On the other hand, chromophobe renal cell carcinoma expresses parvalbumin, which is absent in clear cell and papillary renal cell carcinomas. To further address the relevance of these markers, we studied the expression of CD10 and parvalbumin in 42 samples of chromophobe renal cell carcinoma (seven of which had aggressive features, including invasion beyond the renal capsule, renal vein invasion, metastases, or sarcomatoid transformation), 75 clear cell renal cell carcinomas (eight metastatic) and 51 papillary renal cell carcinomas (two metastatic). CD10 was found in 100% of clear cell renal cell carcinomas, 63% of papillary renal cell carcinomas and in all metastatic cases of both types. At variance with previous studies, we found CD10 expression in from 30 to 90% of the neoplastic cells, in 11 of 42 (26%) chromophobe renal cell carcinomas. The CD10-positive cases included five of the seven (71%) chromophobe renal cell carcinoma with aggressive features. Statistical analysis showed significant association of CD10-positive tumors with clinicopathologic aggressiveness (P=0.003) and mitotic figures (P=0.04). Parvalbumin was strongly expressed in all primary and metastatic chromophobe renal cell carcinomas. Western blot analysis was utilized to confirm the expression of both CD10 and parvalbumin in chromophobe renal cell carcinomas.

Biology and clinical development of vascular endothelial growth factor-targeted therapy in renal cell carcinoma

PURPOSE

To review the biology of renal cell carcinoma (RCC) leading to vascular endothelial growth factor (VEGF) overexpression and the clinical results of VEGF blockade in metastatic RCC.

METHODS

A review of relevant published literature regarding VEGF, von Hippel-Lindau (VHL) gene inactivation and VEGF overexpression in RCC was performed. Further, a review of the mechanism, toxicity, and clinical development of VEGF-targeted therapy in metastatic RCC was undertaken.

RESULTS

VEGF is the major proangiogenic protein that exerts a biologic effect through interaction with cellular receptors. The majority of sporadic clear-cell RCC tumors are characterized by VHL tumor suppressor gene inactivation. The resulting VHL gene silencing leads to VEGF overexpression. An antibody to VEGF (bevacizumab) has demonstrated a significant prolongation of time to disease progression compared with placebo in patients with metastatic RCC. Small molecules with inhibitory effects against the VEGF receptor have undergone initial clinical testing in metastatic RCC with substantial objective response rates.

CONCLUSION

Therapeutic targeting of VEGF in RCC has strong biologic rationale and preliminary clinical efficacy. Further investigation will determine the optimal timing, sequence, and utility of these agents in RCC.

Disturbed balance of expression between XIAP and Smac/DIABLO during tumour progression in renal cell carcinomas

Dysregulation of apoptosis plays an important role in tumour progression and resistance to chemotherapy. The X-linked inhibitor of apoptosis (XIAP) is considered to be the most potent caspase inhibitor of all known inhibitor of apoptosis-family members. Only recently, an antagonist of XIAP has been identified, termed Smac/DIABLO. To explore the relevance of antiapoptotic XIAP and proapoptotic Smac/DIABLO for tumour progression in renal cell carcinomas (RCCs), we analysed XIAP and Smac/DIABLO mRNA and protein expression in the primary tumour tissue from 66 RCCs of all major histological types by quantitative real-time PCR, Western blot and ELISA. X-linked inhibitor of apoptosis and Smac/DIABLO mRNA expression was found in all RCCs. Importantly, the relative XIAP mRNA expression levels significantly increased from early (pT1) to advanced (pT3) tumour stages (P=0.0002) and also with tumour dedifferentiation (P=0.04). Western blot analysis confirmed the tumour stage-dependent increase of XIAP expression on the protein level. In contrast, mRNA and protein expression levels of Smac/DIABLO did not significantly change between early and advanced tumour stages or between low and high tumour grades. Consequently, the mRNA expression ratio between antiapoptotic XIAP and proapoptotic Smac/DIABLO markedly increased during progression from early (pT1) to advanced (pT3) tumour stages. Moreover, RCCs confined within the organ capsule (pT1 and pT2) exhibited a significantly lower XIAP to Smac/DIABLO expression ratio when compared with RCCs infiltrating beyond the kidney (pT3; P=0.01). Thus, our investigation demonstrates that the delicate balance between XIAP and Smac/DIABLO expression is gradually disturbed during progression of RCCs, resulting in a relative increase of antiapoptotic XIAP over proapoptotic Smac/DIABLO, thereby probably contributing to the marked apoptosis resistance of RCC.

Biological significance of p27 and Skp2 expression in renal cell carcinoma. A systematic analysis of primary and metastatic tumour tissues using a tissue microarray technique

p27 (p27/kip1) is involved in cell-cycle control, and loss of p27 expression may result in tumour development and/or progression. Association with Skp2 targets p27 for degradation. Using a tissue microarray technique, 171 primary renal cell carcinomas (RCCs) and 58 RCC metastases were immunostained for p27 and Skp2. p27 Immunoreactivity was noted in 83 of 129 (64%) clear cell, 6 of 22 (27%) chromophobe and 15 of 20 (75%) papillary tumours as well as 44 of 58 (76%) metastases. In clear cell cancers, high p27 expression (> or =50% of tumour cells) decreased with rising tumour stage (50% pT1/pT2 versus 20% pT3; P<0.001) and grade (44% G1/G2 versus 21% G3/G4; P=0.008). None of 22 chromophobe cancers showed high expression in contrast to 46 of 129 (36%) clear cell tumours (P<0.001). Skp2 expression was noted in 8 of 129 (6%) clear cell cancers and 11 of 55 (20%) metastases (P=0.008). Immunoreactivity increased with rising tumour stage (1% pT1/pT2 versus 11% pT3; P=0.03) and grade (1% G1/G2 versus 15% G3/G4; P=0.004) and was associated with sarcomatoid morphology (P<0.001). In multivariate analysis, patients with low p27 expression and Skp2 immunoreactivity in clear cell cancers had a less favourable outcome. In conclusion, p27 and Skp2 proved to be additional biomarkers in renal cancer pathology with both prognostic and diagnostic impact.

Active chemotherapy for sarcomatoid and rapidly progressing renal cell carcinoma

BACKGROUND

Immunotherapy is generally ineffective in patients with sarcomatoid renal cell carcinoma (RCC) and in patients with rapidly progressive metastatic or locally recurrent disease, with a median time to progression of approximately 2 months and a median survival of 4-7 months. Gemcitabine-based regimens have modest antitumor activity, whereas doxorubicin is often used to treat sarcomatoid RCC. Based on the antitumor activity of doxorubicin and gemcitabine in collecting duct carcinoma of the kidney, the authors used this combination to treat selected patients with sarcomatoid or rapidly progressing RCC.

METHODS

Eighteen patients (11 males and 7 females; median age, 53 years; range, 31-81 years) with RCC (56% sarcomatoid; 44% other) were treated at 2 institutions in a collaborative study that was not institutional review board reviewed. Seven patients received previous treatment with interferon or interleukin-2. Sites of metastases included the lung, soft tissue, bone, liver, and brain with 88% of patients having > or = 3 sites of disease. Treatment consisted of doxorubicin (50 mg/m2) and gemcitabine (1500 or 2000 mg/m2) every 2-3 weeks with granulocyte-colony-stimulating factor support.

RESULTS

A median of 5 courses was administered (range, 2-12 cycles). Therapy was well tolerated with no Grade 4 toxicities. Two patients had a complete response, five had a partial response, three had a mixed response, and one had stable disease. The median duration of response was 5 months (range, 2-21+ months).

CONCLUSIONS

These data suggested that the combination of doxorubicin and gemcitabine has antitumor activity in patients with sarcomatoid RCC or with rapidly progressing RCC. A prospective investigation of this combination in RCC is warranted.

Application of TNM, 2002 version, in localized renal cell carcinoma: is it able to predict different cancer-specific survival probability?

OBJECTIVES

To verify whether the latest version of the TNM staging system (2002) could predict different cancer-specific survival in patients with localized renal cell carcinoma (RCC; Stage T1-T2N0M0).

METHODS

According to the 2002 TNM staging system, we reassigned the pathologic stage of 702 patients who had undergone surgical treatment for RCC from 1976 to 2000. We selected 491 patients with localized RCC (pT1-T2N0M0). In 334 patients (68.0%), we had performed radical nephrectomy; in 121 (24.6%), elective nephron-sparing surgery; and in 36 (7.3%), imperative nephron-sparing surgery. Cancer-specific survival was estimated according to the Kaplan-Meier method. The log-rank test and Cox's proportional hazard model was used for univariate and multivariate analysis, respectively.

RESULTS

Of the 491 tumors, 249 (50.7%) were classified as pT1a, 155 (31.6%) as pT1b, and 87 (17.7%) as pT2. The median follow-up was 75 months. The 5-year and 10-year cancer-specific survival probabilities were, respectively, 97.4% and 95.6% in the pT1a patients, 92.5% and 89.8% in the pT1b patients, and 89.3% and 78.5% in the pT2 patients. The survival curve comparison was statistically significant both between pT1a and pT1b (log-rank test, P = 0.01) and between pT1a and pT2 (log-rank test, P = 0.0007). No statistically significant difference was observed between the pT1b and pT2-specific survival probabilities (log-rank test, P = 0.42).

CONCLUSIONS

The 2002 TNM staging system does not seem able to predict different cancer-specific survival between pT1b and pT2 RCC. These data highlight the need to define an optimal breakpoint to stratify patients with localized RCC.