Association of immunohistochemical staining for p53 with metastatic progression and poor survival in patients with renal cell carcinoma

The establishment of kidney cancer organoid line in drug testing

INTRODUCTION

Kidney cancer is a common urological malignancy worldwide with an increasing incidence in recent years. Among all subtypes, renal cell carcinoma (RCC) represents the most predominant malignancy in kidney. Clinicians faced a major challenge to select the most effective and suitable treatment regime for patients from a wide range of modalities, despite improved understanding and diagnosis of RCC.

OBJECTIVE

Recently, organoid culture gained more interest as the 3D model is shown to be highly patient specific which is hypothetically beneficial to the investigation of precision medicine. Nonetheless, the development and application of organotypic culture in RCC is still immature, therefore, the primary objective of this study was to establish an organoid model for RCC.

MATERIALS AND METHODS

Patients diagnosed with renal tumor and underwent surgical intervention were recruited. RCC specimen was collected and derived into organoids. Derived organoids were validated by histological examminations, sequencing and xenograft. Drug response of organoids were compared with resistance cell line and patients' clinical outcomes.

RESULTS

Our results demonstrated that organoids could be successfully derived from renal tumor and they exhibited high concordance in terms of immunoexpressional patterns. Sequencing results also depicted concordant mutations of driver genes in both organoids and parental tumor tissues. Critical and novel growth factors were discovered during the establishment of organoid model. Besides, organoids derived from renal tumor exhibited tumorigenic properties in vivo. In addition, organoids recapitulated patient's in vivo drug resistance and served as a platform to predict responsiveness of other therapeutic agents.

CONCLUSION

Our RCC organoid model recaptiluated histological and genetic features observed in primary tumors. It also served as a potential platform in drug screening for RCC patients, though future studies are necessary before translating the outcomes into clinical practices.

P53 and survivin expression in renal cell carcinoma

Objective

Mutation of p53 is detected in more than 50% of human cancers, expression of p53 has a potential prognostic value in patients with renal cell carcinoma (RCC). Survivin is a member of the inhibitor of apoptosis protein family, its overexpression is observed in many malignancies, including RCC. The aim of the study was to estimate a correlation between survivin and p53 expression in tumor samples and the histologic type of a tumor, tumor stage, tumor grade, and survival of patients.

Materials and Methods

Tumor samples were collected from surgical specimens of 90 patients who underwent radical or partial nephrectomy for RCC between November 2017 and July 2020. Tumors were staged according to the UICC (The Union for International Cancer Control) TNM classification system and histopathologically graded according to Fuhrman nuclear grade system. Histopathological diagnosis was confirmed with standard light microscopic evaluation, using hematoxylin and eosin staining and standard p53 and survivin antibodies.

Results

Positive p53 staining was observed in 36.7% of tumor specimens and 24.4% were survivin positive. There was a statistically significant correlation between p53 or survivin expression and histologic subtype of clear cell RCC as well as Type I and II of papillary RCC. There was a statistically significant correlation between p53 expression and tumor size, stage, and grade. The p53 or survivin expression was related to lower overall survival.

Conclusion

The results of this study suggest that p53 overexpression and survivin positivity in RCC patients could be associated with poor prognosis. Thus, these proteins could be used as prognostic markers in RCC.

p53 and Its Isoforms in Renal Cell Carcinoma—Do They Matter?

p53 is a transcription al factor responsible for the maintenance of cellular homeostasis. It has been shown that more than 50% of tumors are connected with mutations in the Tp53 gene. These mutations cause a disturbance in cellular response to stress, and eventually, cancer development. Apart from the full-length p53, at least twelve isoforms of p53 have been characterized. They are able to modulate p53 activity under stress conditions. In 2020, almost a half of million people around the world were diagnosed with renal cancer. One genetic disturbance which is linked to the most common type of kidney cancer, renal cell carcinoma, RCC, occurs from mutations in the VHL gene. Recent data has revealed that the VHL protein is needed to fully activate p53. Disturbance of the interplay between p53 and VHL seems to explain the lack of efficient response to chemotherapy in RCC. Moreover, it has been observed that changes in the expression of p53 isoforms are associated with different stages of RCC and overall survival. Thus, herein, an attempt was made to answer the question whether p53 and its isoforms are important factors in the development of RCC on the one hand, and in positive response to anti-RCC therapy on the other hand.

Kidney cancer biomarkers and targets for therapeutics: survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, p53, KRAS and AKT in renal cell carcinoma

The incidence of renal cell carcinoma (RCC) is increasing worldwide with an approximate 20% mortality rate. The challenge in RCC is the therapy-resistance. Cancer resistance to treatment employs multiple mechanisms due to cancer heterogeneity with multiple genetic and epigenetic alterations. These changes include aberrant overexpression of (1) anticancer cell death proteins (e.g., survivin/BIRC5), (2) DNA repair regulators (e.g., ERCC6) and (3) efflux pump proteins (e.g., ABCG2/BCRP); mutations and/or deregulation of key (4) oncogenes (e.g., MDM2, KRAS) and/or (5) tumor suppressor genes (e.g., TP5/p53); and (6) deregulation of redox-sensitive regulators (e.g., HIF, NRF2). Foci of tumor cells that have these genetic alterations and/or deregulation possess survival advantages and are selected for survival during treatment. We will review the significance of survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, TP5/p53, KRAS and AKT in treatment resistance as the potential therapeutic biomarkers and/or targets in RCC in parallel with our analized RCC-relevant TCGA genetic results from each of these gene/protein molecules. We then present our data to show the anticancer drug FL118 modulation of these protein targets and RCC cell/tumor growth. Finally, we include additional data to show a promising FL118 analogue (FL496) for treating the specialized type 2 papillary RCC.

Cell-cycle arrest and senescence in TP53-wild type renal carcinoma by enhancer RNA-P53-bound enhancer regions 2 (p53BER2) in a p53-dependent pathway

TP53 is a classic tumor suppressor, but its role in kidney cancer remains unclear. In our study, we tried to explain the role of p53 in kidney cancer through the p53-related enhancer RNA pathway. Functional experiments were used to explore whether P53-bound enhancer regions 2 (p53BER2) has a role in the cell cycle and senescence response of TP53-wild type (WT) renal cancer cells in vitro or vivo. RNA-sequencing was used to identify the potential target of p53BER2. The results showed that the expression level of P53BER2 was downregulated in renal cancer tissues and cell lines, further dual-luciferase experiments and APR-256-reactivated experiments showed p53BER2 expresses in a p53-dependent way. Moreover, knockdown p53BER2 could reverse nutlin-3-induced cytotoxic effect in TP53-WT cell lines. Further exploration showed the downregulation of p53BER2 could reverse nutlin-3-induced G1-arrest and senescence in TP53-WT cell lines. What is more, the knockdown of p53BER2 showed resistance to nutlin-3 treatment in vivo. Additionally, we found BRCA2 could be regulated by p53BER2 in vitro and vivo; further experiment showed p53BER2 could induce cell-cycle arrest and DNA repair by mediating BRCA2. In summary, the p53-associated enhancer RNA-p53BER2 mediates the cell cycle and senescence of p53 in TP53-WT renal cancer cells.

Integrated epigenomic profiling reveals endogenous retrovirus reactivation in renal cell carcinoma

BACKGROUND

Transcriptional dysregulation drives cancer formation but the underlying mechanisms are still poorly understood. Renal cell carcinoma (RCC) is the most common malignant kidney tumor which canonically activates the hypoxia-inducible transcription factor (HIF) pathway. Despite intensive study, novel therapeutic strategies to target RCC have been difficult to develop. Since the RCC epigenome is relatively understudied, we sought to elucidate key mechanisms underpinning the tumor phenotype and its clinical behavior.

METHODS

We performed genome-wide chromatin accessibility (DNase-seq) and transcriptome profiling (RNA-seq) on paired tumor/normal samples from 3 patients undergoing nephrectomy for removal of RCC. We incorporated publicly available data on HIF binding (ChIP-seq) in a RCC cell line. We performed integrated analyses of these high-resolution, genome-scale datasets together with larger transcriptomic data available through The Cancer Genome Atlas (TCGA).

FINDINGS

Though HIF transcription factors play a cardinal role in RCC oncogenesis, we found that numerous transcription factors with a RCC-selective expression pattern also demonstrated evidence of HIF binding near their gene body. Examination of chromatin accessibility profiles revealed that some of these transcription factors influenced the tumor's regulatory landscape, notably the stem cell transcription factor POU5F1 (OCT4). Elevated POU5F1 transcript levels were correlated with advanced tumor stage and poorer overall survival in RCC patients. Unexpectedly, we discovered a HIF-pathway-responsive promoter embedded within a endogenous retroviral long terminal repeat (LTR) element at the transcriptional start site of the PSOR1C3 long non-coding RNA gene upstream of POU5F1. RNA transcripts are induced from this promoter and read through PSOR1C3 into POU5F1 producing a novel POU5F1 transcript isoform. Rather than being unique to the POU5F1 locus, we found that HIF binds to several other transcriptionally active LTR elements genome-wide correlating with broad gene expression changes in RCC.

INTERPRETATION

Integrated transcriptomic and epigenomic analysis of matched tumor and normal tissues from even a small number of primary patient samples revealed remarkably convergent shared regulatory landscapes. Several transcription factors appear to act downstream of HIF including the potent stem cell transcription factor POU5F1. Dysregulated expression of POU5F1 is part of a larger pattern of gene expression changes in RCC that may be induced by HIF-dependent reactivation of dormant promoters embedded within endogenous retroviral LTRs.

Prognostic Biomarkers in Renal Cell Carcinoma: Relevance of DNA Ploidy in Predicting Disease-Related Survival

Objective

To investigate the prognostic value of DNA ploidy, Ki-67 index and p53 expression in relation to disease-related survival in a consecutive series of patients with renal cell carcinoma (RCC).

Material and methods

The study group consisted of 64 RCC patients treated by radical nephrectomy. Histological type, pathological staging and nuclear anaplasia were assessed according to the WHO classification, TNM system and Fuhrman grading criteria, respectively. Ploidy was determined by DNA flow cytometry using two sampling methods (frozen vs paraffin-embedded tissue). Ki-67 and p53 were evaluated by immunohistochemistry techniques using two cutoff points (10% vs mean value) for staining interpretation. Kaplan-Meier and Cox regression analyses were used for prognostic evaluation.

Results

Thirty-one tumors (48.4%) showed DNA diploidy and 33 (51.6%) were DNA aneuploid. Concordance between both ploidy measurement methods was found in 85.5% of cases (p=0.0455). The mean values for Ki-67 and p53 immunostaining were 3.65% (0–23.5%) and 5.90% (0–55.9%), respectively. DNA ploidy significantly correlated with staging, tumor size (pT), nuclear grading, and Ki-67 (mean value cutoff). Ki-67 (10% cutoff) correlated with staging and pT, while p53 (mean value cutoff) was associated with Ki-67 (mean value cutoff). There were significant differences between survival curves for pathological stage, pT, nuclear grade, ploidy, Ki-67 (both cutoffs), and p53 (10% cutoff). By univariate regression analysis, stage III and stage IV, pT3, aneuploidy, high Ki-67 (both cutoffs), and p53 overexpression (10% cutoff) showed significant correlations with worse disease-related survival. In addition, DNA aneuploidy significantly correlated with poor prognosis within stages I/II (p=0.0355) and stages III/IV (p=0.0138) of the disease.

Conclusion

The results indicate that DNA ploidy has relevant prognostic value in RCC, adding useful information to the classic histopathological indicators of clinical outcome.

p53-expression in patients with renal cell carcinoma correlates with a higher probability of disease progression and increased cancer-specific mortality after surgery but does not enhance the predictive accuracy of robust outcome models

OBJECTIVE

Due to lacking external validation, molecular biomarkers are currently not applied for risk-stratification of patients with localized renal cell carcinoma. The objective of this study was to externally validate a molecular multi-marker panel included in a previously proposed prognostic nomogram for the prediction of postoperative disease-free survival.

METHODS AND MATERIALS

Besides pathologic tumor stage (pT) and ECOG-Performance Status, the nomogram includes 5 molecular markers (Ki-67, p53, VEGFR-1 endothelial or epithelial, and VEGF-D epithelial). The validation cohort comprised 343 renal cell carcinoma patients treated by radical nephrectomy or nephron-sparing surgery from 1999 to 2004 at a single academic center (median follow-up: 100 months). By multivariable Cox proportional-hazards regression models, the impact of clinical and molecular markers included in the nomogram on disease progression (DP) and cancer-specific mortality (CSM) was assessed; in addition, it was evaluated to what extent molecular markers added to the models' predictive accuracy (PA).

RESULTS

Of all parameters included in the nomogram, ECOG-PS and pT-stage only revealed a significant impact on both endpoints. p53 (per 10% measures) showed a significant impact on DP (HR = 1.31; P = 0.008), albeit not on CSM, while all other molecular markers did not impact study endpoints. Using Martingale residuals, a cut-off value for p53-expression<20% (negative) vs. ≥20% (positive) yielded the highest impact on DP and CSM. In outcome-models including further well-established histo-pathological factors, p53-expression dichotomized at 20% independently impacted DP (HR = 4.13; P = 0.004) and CSM (HR = 3.74; P = 0.033), while no significant PA gain was achieved.

CONCLUSIONS

p53 showed a statistically significant impact on DP, albeit not on CSM, when applying the 10% expression cut-off as used in the original nomogram, while the prognostic value of all other examined markers included in the nomogram could not be confirmed. When an alternative cut-off of 20% was applied in multivariable models, p53 independently impacted DP and CSM, while the PA was not significantly enhanced. Hence, the clinical significance of p53 is still to be determined. Based on the results of this study it is not recommendable to use p53-expression and the Klatte nomogram in routine clinical decision-making.

MicroRNA-34a: A Key Regulator in the Hallmarks of Renal Cell Carcinoma

Renal cell carcinoma (RCC) incidence has increased over the past two decades. Recent studies reported microRNAs as promising biomarkers for early cancer detection, accurate prognosis, and molecular targets for future treatment. This study aimed to evaluate the expression levels of miR-34a and 11 of its bioinformatically selected target genes and proteins to test their potential dysregulation in RCC. Quantitative real-time PCR for miR-34a and its targets; MET oncogene; gene-regulating apoptosis (TP53INP2 and DFFA); cell proliferation (E2F3); and cell differentiation (SOX2 and TGFB3) as well as immunohistochemical assay for VEGFA, TP53, Bcl2, TGFB1, and Ki67 protein expression have been performed in 85 FFPE RCC tumor specimens. Clinicopathological parameter correlation and in silico network analysis have also implicated. We found RCC tissues displayed significantly higher miR-34a expression level than their corresponding noncancerous tissues, particularly in chromophobic subtype. MET and E2F3 were significantly upregulated, while TP53INP2 and SOX2 were downregulated. ROC analysis showed high diagnostic performance of miR-34a (AUC = 0.854), MET (AUC = 0.765), and E2F3 (AUC = 0.761). The advanced pathological grade was associated with strong TGFB1, VEGFA, and Ki67 protein expression and absent Tp53 staining. These findings indicate miR-34a along with its putative target genes could play a role in RCC tumorigenesis and progression.

Tracking sub-clonal TP53 mutated tumor cells in human metastatic renal cell carcinoma

Renal Cell Carcinomas (RCCs) are heterogeneous tumors with late acquisition of TP53 abnormalities during their evolution. They harbor TP53 abnormalities in their metastases. We aimed to study TP53 gene alterations in tissue samples from primary and metastatic RCCs in 36 patients followed up over a median of 4.2 years, and in xenografted issued from primary RCCs. In 36 primary RCCs systematically xenografted in mice, and in biopsies of metastases performed whenever possible during patient follow-up, we studied p53-expressing tumor cells and TP53 gene abnormalities.We identified TP53 gene alterations in primary tumors, metastases and xenografts. Quantification of tumors cells with TP53 gene alterations showed a significant increase in the metastases compared to the primary RCCs, and, strikingly, the xenografts were similar to the metastases and not to the primary RCCs from which they were derived.Using laser-microdissection of p53-expressing tumor cells, we identified TP53-mutated tumor cells in the xenografts derived from the primary RCC, and in a lung metastasis later developed in one patient. The mutation enabled us to track back their origin to a minority sub-clone in the primary heterogeneous RCC. Combining in situ and molecular analyses, we demonstrated a clonal expansion in a living patient with metastatic RCC.

Gelsolin, NF-κB, and p53 expression in clear cell renal cell carcinoma: Impact on outcome

OBJECTIVES

To examine the prognostic significance of Gelsolin, NF-κB, and p53 in clear cell renal cell carcinoma (CRCC), which has an unpredictable behavior and tendency for recurrence and metastasis.

MATERIALS AND METHODS

Immunohistochemistry was performed on 100 consecutive cases of CRCC using antibodies against Gelsolin, NF-κB, and p53. Tumors were grouped by nuclear grade (NG) as low NG (NG1, 2) or high NG (NG3, 4), and by pathological stage as localized (pT1, 2) or locally invasive (pT3, 4). Clinical stage was grouped as early stage (stage I, II) or late stage (stage III, IV). Evaluation was based on cytoplasmic (NF-κB(Cyt)) and nuclear (NF-κB(Nuc)) expression for NF-κB, nuclear expression for p53, membranous and cytoplasmic expression for Gelsolin.

RESULTS

Gelsolin expression correlated with high NG (p = 0.001), metastasis (p = 0.003), late stage (p = 0.008), and cancer death (p = 0.001). NF-κB(Cyt) expression correlated with high NG (p = 0.002), perirenal invasion (p = 0.010), local invasion (p = 0.020), and late stage (p= 0.003). NF-κB(Nuc) expression failed to predict the prognosis of CRCC. p53 expression correlated with high NG (p = 0.045), lymphovascular invasion (p = 0.05), metastasis (p = 0.001), late stage (p = 0.028), and cancer death (p = 0.034). However, only Gelsolin was found to correlate with disease-specific survival, (p = 0.006), and neither NF-κB nor p53 showed such relation.

CONCLUSION

Expressions of Gelsolin, NF-κB(Cyt), and p53 associated with aggressive behavior of CRCC, while Gelsolin expression specifically indicated poor disease-specific survival. The results of the present study served to determine biomarkers for predicting high-risk patients with CRCC, expected to show aggressive phenotype.

Decreased mRNA expression of GATA1 and GATA2 is associated with tumor aggressiveness and poor outcome in clear cell renal cell carcinoma

GATA-binding proteins 1 (GATA1) and 2 (GATA2) are zinc-finger transcription factors and belong to the GATA family proteins 1-6. GATA1 interacts with the TP53 tumor suppressor gene, and both GATAs have been shown to be involved in cell growth, apoptosis, and tumorigenesis of several solid tumors. GATA1 and GATA2 expression alterations are associated with poor survival and adverse clinicopathology in prostate and colorectal cancer, while the significance and prognostic value in clear cell renal cell carcinoma (ccRCC) has not been investigated as yet. We investigated relative messenger RNA (mRNA) expression levels of GATA1 and GATA2 in 77 ccRCC and 58 paired adjacent noncancerous renal tissues by quantitative real-time reverse-transcribed PCR. Relative mRNA expression levels were determined using the ΔΔCt method. GATA1 and GATA2 expression levels were significantly decreased in tumor tissues compared with normal tissues (p < 0.001, paired t test). In univariate logistic regression analysis, decreased GATA1 and GATA2 expression levels were associated with advanced tumor disease (p = 0.005 and 0.008), positive distant metastasis (p = 0.03 and 0.001), and lymph node metastasis status (p = 0.011 and 0.038). Reduced expression levels of GATA1 and GATA2 were associated with an increased risk of disease recurrence (p = 0.005 and 0.006; hazard ratio = 0.05 and 0.21). Pairwise bivariate analysis after adjusting for clinicopathological parameters revealed relative mRNA expression of GATA1, but not GATA2, as an independent candidate prognosticator for ccRCC. Our results support that GATA1 and GATA2 are involved in ccRCC tumor biology possibly affecting tumor development and aggressiveness.

Prognostic biomarkers in renal cell carcinoma

A hallmark of renal cell carcinoma is its variable prognosis. Surgical resection of primary renal cell carcinoma can be curative when the disease is localized. However, approximately 20% of patients with early stages of localized renal cell carcinomas subsequently develop metastasis after the primary tumor is removed. The median survival for patients with metastatic disease is approximately 13 months. Therefore, there is a great need for biomarkers to predict metastasis and prognosis. Many prognostic biomarkers were studied in the past decade. In recent years, several promising biomarkers, including CAIX, B7-H1 and IMP3, have also been identified by large retrospective studies. Further validation of these biomarkers is essential to transfer the research data into clinical practice. Eventually, an outcome prediction model with biomarkers, staging system and other risk factors will identify high-risk patients with likelihood of progression and formulate different follow-up protocols or systematic treatments for these patients.

Differential expression of prognostic proteomic markers in primary tumour, venous tumour thrombus and metastatic renal cell cancer tissue and correlation with patient outcome

Renal cell carcinoma (RCC) is the most deadly of urological malignancies. Metastatic disease affects one third of patients at diagnosis with a further third developing metastatic disease after extirpative surgery. Heterogeneity in the clinical course ensures predicting metastasis is notoriously difficult, despite the routine use of prognostic clinico-pathological parameters in risk stratification. With greater understanding of pathways involved in disease pathogenesis, a number of biomarkers have been shown to have prognostic significance, including Ki67, p53, vascular endothelial growth factor receptor 1 (VEGFR1) and ligand D (VEGFD), SNAIL and SLUG. Previous pathway analysis has been from study of the primary tumour, with little attention to the metastatic tumours which are the focus of targeted molecular therapies. As such, in this study a tissue microarray from 177 patients with primary renal tumour, renal vein tumour thrombus and/or RCC metastasis has been created and used with Automated Quantitative Analysis (AQUA) of immunofluorescence to study the prognostic significance of these markers in locally advanced and metastatic disease. Furthermore, this has allowed assessment of differential protein expression between the primary tumours, renal vein tumour thrombi and metastases. The results demonstrate that clinico-pathological parameters remain the most significant predictors of cancer specific survival; however, high VEGFR1 or VEGFD can predict poor cancer specific survival on univariate analysis for locally advanced and metastatic disease. There was significantly greater expression of Ki67, p53, VEGFR1, SLUG and SNAIL in the metastases compared with the primary tumours and renal vein tumour thrombi. With the exception of p53, these differences in protein expression have not been shown previously in RCC. This confirms the importance of proliferation, angiogenesis and epithelial to mesenchymal transition in the pathogenesis and metastasis of RCC. Importantly, this work highlights the need for further pathway analysis of metastatic tumours for overcoming drug resistance and developing new therapies.

Targeted therapy in renal cancer

Renal cell cancer (RCC) has an increasing incidence internationally and is a disease for which there have been limited therapeutic options until recently. The last decade has seen a vastly improved understanding of the biological and clinical factors that predict the outcome of this disease. We now understand some of the different molecular underpinnings of renal clear cell carcinoma by mutation or silencing of the von Hippel Lindau (VHL) gene and subsequent deregulated proliferation and angiogenesis. Survival in advanced disease is predicted by factors (performance status, anemia, hypercalcemia, and serum lactate dehydrogenase, time from diagnosis to recurrence) incorporated into the Memorial Sloan Kettering Cancer Center (MSKCC) criteria (also referred to as 'Motzer' criteria). These criteria allow classification of patients with RCC into good, intermediate and poor risk categories with median overall survivals of 22 months, 12 months and 5.4 months, respectively. Predicated upon these advances, six new targeted drugs (sorafenib, sunitinib, temsirolimus, everolimus, bevacizumab and pazopanib) have been tested in well-designed phase III trials, selected or stratified for MSKCC risk criteria, with positive results. All of these new drugs act at least in part through vascular endothelial growth factor (VEGF) mediated pathways with other potential therapeutic impact on platelet-derived growth factor (PDGF), raf kinase and mammalian target of rapamycin (mTOR) pathways. Importantly, data from each of these trials show a consistent doubling of progression-free survival (PFS) over prior standard of care treatments. In addition, sorafenib, sunitinib and temsirolimus, have demonstrated significant overall survival (OS) benefits as well; further follow-up is required to determine whether the disease control exhibited by everolimus and pazopanib will translate into a survival advantage. These drugs are generally well tolerated, as demonstrated by quality-of-life improvement in clinical trials, and result in clinical benefit for in excess of 70% of patients treated. They have challenged the traditional outcomes of clinical trial design by achieving their benefits with relatively few radiographic responses, but high rates of disease stability. The unique side-effect profile coupled with the chronicity of therapy requires increased vigilance to maximize exposure to the drugs while maintaining quality of life and minimizing toxicity. This review focuses on the background, clinical development and practical use of these new drugs in RCC.

p53 and MDM2 in renal cell carcinoma: biomarkers for disease progression and future therapeutic targets?

Renal cell carcinoma (RCC) is the most common type of kidney cancer and follows an unpredictable disease course. To improve prognostication, a better understanding of critical genes associated with disease progression is required. The objective of this review was to focus attention on 2 such genes, p53 and murine double minute 2 (MDM2), and to provide a comprehensive summary and critical analysis of the literature regarding these genes in RCC. Information was compiled by searching the PubMed database for articles that were published or e-published up to April 1, 2009. Search terms included renal cancer, renal cell carcinoma, p53, and MDM2. Full articles and any supplementary data were examined; and, when appropriate, references were checked for additional material. All studies that described assessment of p53 and/or MDM2 in renal cancer were included. The authors concluded that increased p53 expression, but not p53 mutation, is associated with reduced overall survival/more rapid disease progression in RCC. There also was evidence that MDM2 up-regulation is associated with decreased disease-specific survival. Two features of RCC stood out as unusual and will require further investigation. First, increased p53 expression is tightly linked with increased MDM2 expression; and, second, patients who have tumors that display increased p53 and MDM2 expression may have the poorest overall survival. Because there was no evidence to support the conclusion that p53 mutation is associated with poorer survival, it seemed clear that increased p53 expression in RCC occurs independent of mutation. Further investigation of the mechanisms leading to increased p53/MDM2 expression in RCC may lead to improved prognostication and to the identification of novel therapeutic interventions.

The expression of thrombospondin-1 and p53 in clear cell renal cell carcinoma: its relationship to angiogenesis, cell proliferation and cancer specific survival

PURPOSE

We evaluated possible associations among thrombospondin-1, p53 expression, microvessel density, cell proliferation index, nuclear grade, tumor stage and continuously coded tumor size in clear cell renal cell carcinoma. The value of thrombospondin-1 as a prognostic marker in clear cell renal cell carcinoma was examined.

MATERIALS AND METHODS

A total of 172 consecutive patients with clear cell renal cell carcinoma treated with radical nephrectomy were initially enrolled in the study. However, due to technical problems and lack of material 12 cases were excluded from analysis. A total of 68 patients (43%) died of renal cell carcinoma and 46 (29%) died of other diseases. Median followup for the surviving 42 patients (29%) was 13.8 years. The expression of thrombospondin-1, Ki-67 (proliferation index), p53 and microvessel density were analyzed without knowledge of the clinical outcome on formalin fixed, paraffin embedded tissues.

RESULTS

Low expression of thrombospondin-1 was significantly associated with advanced stage (p <0.001), high nuclear grade (p = 0.001), positive p53 status (p <0.001), high proliferation index (p = 0.001), high microvessel density (p = 0.036) and tumor progression (p = 0.006). On univariate analysis thrombospondin-1, microvessel density, proliferation index, p53 over expression, TNM stage, Fuhrman nuclear grade (p <0.001) and continuously coded tumor size (p = 0.002) had a significant impact on survival. Multivariate analysis revealed TNM stage, thrombospondin-1, p53, Ki-67 (proliferation index) and microvessel density were independent predictors of cancer specific survival.

CONCLUSIONS

Thrombospondin-1 expression is strongly associated with prognostic tumor features in clear cell renal cell carcinoma and is an independent prognostic factor for cancer specific survival. Our findings revealed a significant correlation among p53, proliferation index, microvessel density and thrombospondin-1 expression, and indicate that thrombospondin-1 may have an impact on angiogenesis, proliferation and tumor aggressiveness in clear cell renal cell carcinoma.

Predicting disease progression after nephrectomy for localized renal cell carcinoma: the utility of prognostic models and molecular biomarkers

Disease progression after nephrectomy for pathologically localized renal cell carcinoma (RCC) is associated with a significant mortality rate, given the limited efficacy of available treatment regimens for metastatic disease. As such, several adjuvant trials have been designed to treat patients at particularly high risk for postsurgical RCC progression. Several different prognostic models designed to identify patients at high risk of disease progression are available. Although these available predictive models provide a reasonable assessment of patients' risks of disease progression, the accuracy of these models may further be improved via the incorporation of molecular prognostic biomarkers. Although numerous candidate molecules have been described, few have been specifically assessed for the association with disease progression after nephrectomy. IMP-3, CXCR3, p53, Survivin, cIAP1, B7-H1, and B7-H4 have all been associated with disease progression after nephrectomy. The incorporation of 1 or several of these biomarkers may increase the accuracy of currently available prognostic models and thereby facilitate the appropriate use of adjuvant therapies aimed at preventing future disease progression. As such, the authors review the current prognostic tools for predicting disease progression for localized RCC, and detail studies to date that have evaluated various biomarkers in this setting.

Molecular markers for predicting prognosis of renal cell carcinoma

Metastatic or recurrent renal cell carcinoma (RCC) carries a poor prognosis and long term survival is rare. However, many small RCCs that are incidentally discovered have an indolent course even without treatment. The variability in clinical outcome is a reflection of the underlying tumor biology. Currently, clinical variables such as tumor stage and histologic grade are widely accepted surrogates for tumor-specific cellular and molecular processes. Ongoing advances in genomic and proteomic technologies have produced an expanding list of molecular markers for predicting prognosis. We review expression array studies evaluating molecular signatures for predicting prognosis in patients with RCC and describe specific prognostic markers that have been validated in at least 50 cases of RCC.

Synergy of Interferon-α and 5-Fluorouracil in Human Renal Cell Carcinoma Requires p53 Activity

OBJECTIVES

Immunochemical therapy combining cytokines and chemotherapeutic agents is expected to be effective for treating advanced renal cell carcinoma (RCC). We investigated the mechanism underlying the synergism of interferon-alpha (IFN-alpha) and 5-fluorouracil (5-FU) and the effect of p53 status on the synergy of the combined therapy in RCC cell lines.

METHODS

The synergy of IFN-alpha and 5-FU was analyzed by isobolographic analysis in five RCC cell lines. The effect of combined treatment on apoptosis induction was measured by flow cytometric analysis, Hoechst staining, and caspase activity assay; PCNA expression was investigated by Western blotting to examine the effect of combined treatment on the antiproliferative effect.

RESULTS

We demonstrated synergy of IFN-alpha and 5-FU in five RCC cell lines with wild-type p53. IFN-alpha suppressed the proliferation of RCC cells via G1 or G2/M cell cycle arrest without inducing apoptosis, whereas 5-FU induced apoptosis in a dosage-dependent manner. IFN-alpha enhanced the apoptosis of RCC cells induced by 5-FU, whereas 5-FU did not increase the antiproliferative effect of IFN-alpha. However, the synergistic inhibition by IFN-alpha and 5-FU was abolished when the cell lines were transfected with p53 dominant-negative vector.

CONCLUSIONS

The synergy of IFN-alpha and 5-FU requires p53 activity, suggesting that p53 status may serve as a predictive factor for response to the combination therapy. Because metastatic RCC frequently has p53 mutations, therapy restoring p53 may markedly improve the response rate of immunochemical therapy combining IFN-alpha and 5-FU.

Lipid peroxidation and renal cell carcinoma: further supportive evidence and new mechanistic insights

We have recently proposed lipid peroxidation as a unifying mechanistic pathway by which several seemingly unrelated risk/protective factors (obesity, hypertension, diabetes, smoking, oophorectomy/hysterectomy, parity, antioxidants) affect renal cell carcinoma development. In experimental studies, increased lipid peroxidation is a principal mechanistic pathway in renal carcinogenesis induced by different chemicals. In this communication, we provide additional lines of evidence that further support a role for lipid peroxidation on renal cell cancer development. (1) Lipid peroxidation may explain the role of other risk (analgesic use, pre-eclampsia) or protective (alcohol intake, oral contraceptives) factors for renal cell carcinoma. (2) Additional experimental evidence supports lipid peroxidation as an important mechanism in renal carcinogenesis, and (3) Existing evidence support a cross-talk between the lipid peroxidation pathway and other pathways that are relevant to renal carcinogenesis, such as apoptosis, VHL, and possibly other pathways.

p53 IS AN INDEPENDENT PREDICTOR OF TUMOR RECURRENCE AND PROGRESSION AFTER NEPHRECTOMY IN PATIENTS WITH LOCALIZED RENAL CELL CARCINOMA

PURPOSE

We determined which clinical and molecular variables can predict cancer recurrence in patients following surgical management for localized renal cell carcinoma (RCC).

MATERIALS AND METHODS

From a custom kidney cancer tissue microarray containing tumors specimens from 350 patients 193 undergoing nephrectomy for localized RCC at our institution between 1989 and 2000 were identified. The array was then analyzed by immunohistochemistry for certain molecular markers, namely CA9, CA12, Ki67, gelsolin, p53, EpCAM, pTEN and vimentin. The medical records of these patients were then reviewed for age, sex, TNM stage, tumor size, nuclear grade, Eastern Cooperative Oncology Group (ECOG) performance status, recurrence status and, when applicable, time to recurrence. Cox regression analyses were done to determine clinical and molecular predictors of time to tumor recurrence.

RESULTS

Of the patients 15% demonstrated evidence of tumor recurrence following nephrectomy (29 of 193). Univariate Cox regression demonstrated that tumor size, T stage, grade, ECOG performance status, Ki67, EpCAM and p53 were significantly associated with recurrence (p <0.05). A multivariate Cox regression model showed that T stage (p = 0.018), ECOG (p = 0.004) and p53 (p = 0.003) were the 3 most significant predictors. p53 expression correlated significantly with nuclear grade (Pearson correlation 0.22, p = 0.023) but not with any other clinical factors. Patients with localized tumors demonstrating mean p53 staining values above and below 20% of cells had recurrence rates of 37.7% and 14.4%, respectively (RR = 3.28, p = 0.018).

CONCLUSIONS

p53 is a significant molecular predictor of tumor recurrence, as identified in patients undergoing treatment for localized RCC.

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.

Value of p53 as a prognostic marker in histologic subtypes of renal cell carcinoma: a systematic analysis of primary and metastatic tumor tissue

OBJECTIVES

To investigate the histologic subtypes of renal cell carcinoma (RCC) with respect to differences in immunoreactivity for p53 and its impact on prognosis. The prognostic significance of p53 in RCC remains to be defined.

METHODS

A total of 188 primary RCC and 58 RCC metastasis specimens were stained immunohistochemically for p53 overexpression using a tissue microarray technique. p53 overexpression was analyzed semiquantitatively with respect to its association with pT stage, grade, histologic subtype, and sex using the chi-square test or Fisher's exact test. The impact on metastasis-free survival was analyzed using the Kaplan-Meier method and log-rank test. For conventional RCC, a multivariate analysis, including pT stage, grade, and p53 immunoreactivity was performed.

RESULTS

Sufficient tumor tissue was present in 184 (97.9%) of 188 primary and 56 (96.6%) of 58 metastatic cases. p53 overexpression was found in 42 (22.8%) of 184 primary RCC specimens and in 29 (51.8%) of 56 metastasis specimens (P = 0.0001). p53 overexpression for papillary, chromophobe, and conventional RCC was 70.0%, 27.3%, and 11.9%, respectively (P <0.0001). No association of p53 immunoreactivity with the other parameters investigated was found. Regarding prognosis, a statistically significant difference in metastasis-free survival between p53-positive and p53-negative tumors was found only for conventional RCC (P = 0.0005) and not for the other subtypes (P = 0.19). Multivariate analysis proved grade (P <0.0001), pT stage (P = 0.01), and p53 overexpression (P = 0.01) to be independent prognostic factors for conventional RCC.

CONCLUSIONS

p53 overexpression was significantly more frequent in "nonconventional" RCC subtypes, especially papillary RCC, compared with conventional RCC in our study. However, p53 immunoreactivity is a prognostic marker only for conventional RCC.

Daphnetin induced differentiation of human renal carcinoma cells and its mediation by p38 mitogen-activated protein kinase

Daphnetin has been shown to be a potent in vitro anti-proliferative agent to the human renal cell carcinoma (RCC) cell line, A-498. In the present study, we investigated its effects on mitogen-activated protein kinase (MAPK) signalling along with cell cycle events and cellular differentiation. Daphnetin-activated p38, however, higher concentrations were required to inhibit ERK1/ERK2. In addition, it did not activate SAPK or induce apoptosis, but instead inhibited S phase cell cycle transition of A-498 cells at low concentrations and time of exposure. In addition, a late G(1), early S phase inhibition was observed at higher concentrations and time of exposure, indicating that the mechanism of daphnetin-induced differentiation was concentration dependent. Increased expression of the epithelial differentiation markers cytokeratins 8 and 18, correlated with increasing concentrations of daphnetin, while pre-treatment with a specific p38-inhibitor, served to limit this effect. There was no evidence that P-glycoprotein (P-gp) mediated multi-drug resistance (MDR) played a role in the anti-proliferative activity of daphnetin. Consequently, we concluded that p38 MAP kinase is intrinsically involved in mediating the effect of daphnetin in A-498 cells, suggesting that this drug may act by promotion of cellular maturation, and consequently may represent a novel low toxic approach for the treatment of poorly differentiated RCCs.

Novel concepts in the staging of renal cell carcinoma

The incidence of renal cell carcinoma (RCC) continues to rise steadily; unfortunately, our ability to cure patients with metastatic RCC remains limited. When developing and evaluating new treatment protocols, it is important to consider the role of prognostic factors, often defined as pretreatment features, that are predictive of outcome. The complexity and variability of patients' individual clinical outcome and the recently recognized limitation of conventional staging systems have lead to the formulation of integrated prognostic staging systems. In this review, we discuss the evolution of various clinically relevant integrated staging systems for RCC.

Clinical significance of p53, mdm2, and bcl-2 proteins in renal cell carcinoma

OBJECTIVES

To improve our understanding of the clinical relevance of p53, mdm2, and bcl-2 protein overexpression in renal cell carcinoma, we retrospectively investigated the immunohistochemical expression of p53, murine double minute 2 (mdm2), and bcl-2 and the relationship of this expression to clinicopathologic characteristics. p53 regulates the transcription of downstream effectors such as the oncoprotein mdm2, and bcl-2 has been shown to inhibit apoptosis triggered by wild-type p53.

METHODS

The expression of p53, mdm2, and bcl-2 protein was studied by immunohistochemical methods in paraffin-embedded nephrectomy specimens from 112 patients whose clinicopathologic data confirmed renal cell carcinoma.

RESULTS

The expression of the p53 and bcl-2 protein was recognized in 15 (13.4%) and 52 (42.0%) cases, respectively; the expression of the mdm2 protein, however, was seen in only 2 cases (1.8%). No correlation was noted between these three proteins and any clinicopathologic parameters, except p53 expression and Stage T1-2/T3-4 (P = 0.0208). However, in multivariate analysis, stage (hazard ratio 3.586; P = 0.0002), expression of p53 (hazard ratio 6.090; P = 0.0126) and of mdm2 (hazard ratio 22.016; P = 0.0156), and coexpression of p53/mdm2 (hazard ratio 6.146; P = 0.0005) demonstrated a statistically significant effect on prognosis by proportional hazards regression tests.

CONCLUSIONS

Our results indicate that stage, p53 expression, mdm2 expression, and coexpression of p53/mdm2 are useful to predict the clinical outcome in patients with renal cell carcinoma.

Chromosome 9 and 17 aberrations and p53 gene deletion detected by fluorescence in situ hybridization in renal-cell carcinoma

BACKGROUND AND PURPOSE

Nuclear grade and tumor stage have been reported as important prognostic factors for renal-cell carcinoma (RCC), but tumors of similar stage and grade can still exhibit wide variations in biologic behavior and clinical outcome. Fluorescence in situ hybridization (FISH) has recently been applied to RCC. This study was designed to investigate whether aberrations of some chromosomes or genes detected by FISH are related to the progression of RCC.

MATERIALS AND METHODS

We examined 52 patients with RCC, including 31 patients without metastasis (control group) and 21 patients with either concurrent or subsequent metastasis (metastatic group). Paraffin-embedded specimens of the primary tumors were analyzed by FISH for aberrations of chromosomes 9 and 17, as well as for p53 gene alterations.

RESULTS

The incidence of aberrations of chromosome 9 was higher in the metastatic group than in the control group. The p53 gene deletion rate was significantly higher in the metastatic group than in the control group. When the metastatic group was separated into concurrent and subsequent metastasis subgroups, chromosome 17 aberrations as well as p53 gene deletion were significantly more common in the subsequent metastasis group than in the control group.

CONCLUSIONS

Numerical aberrations of chromosome 17 as well as p53 gene deletion detected by FISH may be markers of chromosomal instability in RCC and are probably associated with an increased propensity to metastasize.

Expression of vascular endothelial growth factor in renal cell carcinoma and the relation to angiogenesis and p53 protein expression

BACKGROUND AND OBJECTIVES

Vascular endothelial growth factor (VEGF) seems to play an important role in tumor angiogenesis. The tumor-suppressor gene p53 has been thought to regulate VEGF expression. We investigated the effect of VEGF expression on renal cell carcinoma (RCC) and the correlation between the expression of VEGF and tumor angiogenesis and p53 protein expression.

METHODS

Sixty-two RCCs were examined by immunohistochemical studies with anti-VEGF, anti-p53, and anti-CD34 antibodies.

RESULTS

Forty tumors (80.6%) were classified as VEGF positive, and 28 tumors (45.2%) were positive for p53 protein. The microvessel density was 75.3 +/- 33.5. A significant correlation was found between VEGF expression and both the nuclear grade (P < 0.05) and the TNM stage (P < 0.05). The tumors with VEGF expression had a significantly higher microvessel density than those without VEGF expression (P < 0.01). There was no statistically significant correlation between p53 protein and VEGF expression. No statistically significant differences in survival were found to be associated with microvessel density, VEGF expression or p53 protein expression. By using multivariate survival analyses, nuclear grade (P < 0.05) and TNM stage (P < 0.05) were the only independent prognostic factors.

CONCLUSIONS

Our data do not show a direct regulation of VEGF expression by p53. We suggest that VEGF expression plays a role in the promotion of angiogenesis in RCC.

Renal cell carcinoma

Several renal cell carcinoma (RCC) prognostic factors show promise, including K1-67, p53/mdm-2, and vascular endothelial growth factor. The combination of increased incidence of RCC and diagnosis during earlier stages has generated interest in local therapeutic options. Nephron-sparing surgery and laparoscopic nephrectomy continue to gain support and may become the standard of care in select patients. Standard therapy for metastatic disease continues to be cytokine-based therapy with little benefit gained from adding granulocyte-macrophage-colony-stimulating factor, retinoic acid, or adoptive immunotherapy. The addition of chemotherapy, such as capecitabine, floxuridine, and vinblastine, may increase the effectiveness of immunotherapy; nonmyeloablative stem cell transplantation has shown early promise in metastatic disease.

p53 immunoreactivity correlates with Ki-67 and bcl-2 expression in renal cell carcinoma

This study assessed the relation of proliferation, inhibition of apoptosis, and the p53 tumor suppressor protein expression in clear renal cell carcinoma (RCC). Archival pathological specimens from 43 patients treated for RCC were obtained. Median follow-up for the patients was 52 months (range 2.5 months to 178 months). Immunostaining of paraffin tissue sections was carried out for four different markers: a) Ki-67, a marker for cellular proliferation; b) p53/DO7, c) p53/pAb240, antibodies for the p53 protein; and d) bcl-2, a marker for inhibition of apoptosis (programmed cell death). One thousand cells were counted per slide at 400x magnification. Staining of >/=10% of cells was considered positive and <10% negative. Fisher exact contingency tables were used for correlation between markers, tumor grade and stage. A significant correlation was found between Ki-67 and p53 immunoreactivity samples, P=0.0001. Interestingly, a significant association was found if Ki-67 and bcl-2 scores were combined and correlated with p53, P=0.009. Results showed no correlation between any of the immunohistochemical markers and grade or stage. In addition, Kaplan-Meier survival curves demonstrated no significant difference between patients' tumors that was scored immunoreactive negative vs. positive for Ki-67, p53, or bcl-2. This study indicates that p53 expression correlates with proliferation, and inhibition of programmed cell death in RCC.

p53 expression in correlation to clinical outcome in patients with renal cell carcinoma

OBJECTIVE

The aim of this study was to evaluate the role of p53 as prognostic factor in renal cell carcinoma (RCC) and its relation to clinicopathological factors.

MATERIAL AND METHODS

The nuclear accumulation of p53 protein was determined by immunohistochemical analysis in RCC specimens from 90 patients and was correlated with clinical stage, grade, DNA ploidy, S-phase fraction and cancer-specific survival.

RESULTS

p53 overexpression was observed in 17 of 90 (19%) tumours. There was a significant correlation to stage (p = 0.016) and grade (p = 0.020) but not to DNA ploidy or S-phase. Patients with high p53 immunoreactivity had shorter cancer-specific survival (p = 0.003) than those with normal p53 protein expression. This difference was found in papillary and chromophobe tumour types (p < 0.0001) but not in conventional RCC.

CONCLUSIONS

In patients with RCC, significant correlations between p53 protein expression and tumour stage, grade and survival time were observed. For patients with chromophobe and papillary tumour types, but not in conventional RCC, p53 immunoreactivity gave prognostic information, suggesting that the prognostic differences in p53 immunoreactivity might be due to disparate genetic abnormalities in the different RCC types.

Biomarkers of renal cell carcinoma. Past and future considerations

Renal cancer includes several distinct entities with a range of biologic and clinical behaviors from relatively indolent to extremely aggressive tumors. Although conventional prognostic factors such as stage and grade are quite useful, other clinical, laboratory, and pathologic findings are now believed to have additional predictive values. This article reviews the literature on the potential utility of biomarkers in renal cell carcinoma. To date, only a few biomarkers, such as Ki-67, appeared to be potentially useful for monitoring renal cancer patients. New biomarkers including MN/CA9 and circulating cell detection require further and extensive studies to assess their potential clinical utility.

Prognostic influence of p53 nuclear overexpression in colorectal carcinoma

PURPOSE

The aim of this study was to test the prognostic influence of p53 nuclear overexpression in colorectal carcinoma.

METHODS

We performed an analysis of the prognostic influence of the nuclear overexpression of p53 with immunohistochemistry in 126 cases of colorectal carcinoma operated on in our hospital between 1987 and 1992, with a minimum follow-up time of 60 months (5 years).

RESULTS

Our results show a statistically significant prognostic influence of p53 overexpression on disease-free survival time, but not on the overall survival time, in univariate analysis, but this influence is lost in multivariate analysis.

CONCLUSIONS

Our results confirm recent reports by other authors that failed to show the independent prognostic value of p53 in colorectal carcinoma.

Evaluation of the clonal relationship between primary and metastatic renal cell carcinoma by comparative genomic hybridization

The outcome of patients with renal cell carcinoma is limited by the development of metastasis after nephrectomy. To evaluate the genetic basis underlying metastatic progression of human renal cell carcinoma in vivo, we performed a comparative genomic hybridization analysis in 32 clear-cell renal-cell carcinoma metastases. The most common losses involved chromosomes 3p (25%), 4q (28%), 6q (28%), 8p (31%), and 9p (47%). The most common gains were detected at 17q (31%) and Xq (28%). There was one high-level gene amplification at chromosome 11q22-23. The mean number of aberrations in lymph node (4.8 +/- 2.8) and lung metastases (6.2 +/- 4.0) was lower than in other hematogenous metastases (11.5 +/- 8.7, P < 0.05), suggesting that hematogenous dissemination is linked to an acquisition of complex genomic alterations. As genetic differences between primary tumors and metastases give information on genetic changes that have contributed to the metastatic process, relative DNA sequence copy number changes in 19 matched tumor pairs were compared. Genomic changes, which frequently occurred in metastases but not in the corresponding primary tumor were losses of 8p and 9p and gains of 17q and Xq. An abnormal function of genes in these regions may contribute to the metastatic process. According to a statistical analysis of shared genetic changes in matched tumor pairs, a high probability of a common clonal progenitor was found in 11 of 19 patients (58%). Six metastases (32%) were genetically almost completely different from the primary, suggesting that detection of genomic alterations in primary tumors gives only a restricted view of the biological properties of metastatic renal cell carcinoma.

Renal cell carcinoma: a paradigm of lanthanic disease

Renal cell carcinoma is characterized by varied and sometimes obscure manifestations, which include unusual metastatic sites and paraneoplastic and vascular syndromes. In this review, uncommon metastatic sites and their clinical significance are discussed, particularly the thyroid, nasal structures, vagina, and gastrointestinal sites. Paraneoplastic syndromes appear to be related predominantly to cytokines or immunologic mechanisms. Vascular syndromes are related to the tendency of the tumor to spread by direct venous extension and to complications related to the vascularity of the tumor or its metastases. The recognition of unusual manifestations of renal cell carcinoma is important because these syndromes may lead to the diagnosis. Moreover, paraneoplastic syndromes and vascular findings may not indicate unresectability or incurability.

Expression of p73, a novel protein related to the p53 tumour suppressor p53, and apoptosis in cholangiocellular carcinoma of the liver

p73, the first homologue of the tumour suppressor protein p53, was recently discovered on chromosome 1p36 and has been shown to induce apoptosis in a p53-like manner. The present study was performed with the aim of investigating the expression of p53, its new homologue p73 and the occurrence of apoptosis in cholangiocellular carcinoma. Protein levels of p73 were examined in 41 patients with curatively (R0-) resected cholangiocellular carcinomas with an antiserum, raised against a peptide in the N-terminal domain of p73. The incidence of mutations in the p53 gene was analysed by direct sequencing and also immunohistochemically. Apoptotic cell death was assessed using in-situ end-labelling (ISEL) technique in combination with morphological criteria. The results obtained were correlated with patient survival. Immunostaining of p73 protein was detected in 17/41 carcinomas examined (41%). The immunoreactivity was confined to the cell nucleus. In 15/41 patients (37%), mutations of the p53 gene were observed. Eleven out of these 15 patients stained also positive for p73. In contrast, out of 26 patients without any detectable p53 mutation, only six exhibited p73 immunostaining. We failed to observe a correlation between p73 expression or p53 and apoptosis within a given tumour. Survival analysis including the parameters stage and grade of disease, p73 and p53, and also apoptosis, showed that tumour stage and grade as well as p53 and p73 were significantly related to prognosis. In Cox regression survival analysis, however, only extent of primary tumour and lymph node status had an independent prognostic impact. Our results with a high prevalence of p73 within tumours harbouring mutated p53 gene suggest that p73 could compensate for p53 function. We failed to establish p73 or p53 as independent prognostic factors in cholangiocellular carcinoma of the liver.

Biologic behavior of and p53 overexpression in multifocal renal cell carcinoma of clear cell type: an immunohistochemical study correlating grading, staging, and proliferation markers

BACKGROUND

In the treatment of small renal cell carcinoma (RCC), there is controversy between radical and nephron-sparing surgical treatment because of the risk of tumor multifocality. The biologic behavior of multifocal RCC compared with that of unifocal RCC is not well investigated, and the relevance of p53 and the proliferation markers MIB-1 and proliferating cell nuclear antigen (PCNA) to multifocal RCC is not yet established.

METHODS

In this study, p53 protein overexpression was investigated immunohistochemically in 27 multifocal and 65 unifocal clear cell RCCs using a monoclonal antibody (DO-1). The nuclear expression of p53 was compared with the expression of PCNA and MIB-1 (Ki-67 antigen) and other prognostic factors, including grade and stage.

RESULTS

Thirty-three RCCs (35.9%) had p53 positive nuclear staining. MIB-1 positivity was significantly higher in p53 positive tumors than in p53 negative tumors. PCNA positivity was not different in p53 positive tumors compared with p53 negative tumors. Proliferation marker expression was not associated with tumor focality. p53 overexpression was more often found in unifocal tumors than in multifocal tumors. Intracellular accumulation of the p53 protein was related to tumor grade but not to the T classification of tumor stage. In addition, lymph node involvement was significantly associated with p53 overexpression in tumors of the kidney. Focality did not influence progression free survival.

CONCLUSIONS

This study demonstrated that there is no difference in the proliferative activity or biologic behavior of multifocal and unifocal tumors.

Kidney cancer

In the USA, the incidence of kidney cancer has increased 43% since 1973. The risk of the disorder is higher in men than in women and increases with age. The von Hippel-Lindau tumour-suppressor gene is inactivated in over 75% of sporadic cases. Metastatic disease is present in 20-30% of patients at diagnosis. Early-stage kidney cancer is treated with a radical nephrectomy, but under certain circumstances a partial nephrectomy may be done. Tumour thrombus into the vena cava or right atrium requires thoracotomy and hypothermic circulatory arrest for successful removal of the tumour, but should not be done if extensive nodal or frank metastatic disease is present. Interleukin-2 is the systemic therapy of choice for metastatic disease at present, with long-term relapse-free survival of 5-8%. Several treatments including anti-angiogenesis drugs, cyclin-dependent kinase inhibitors, and differentiating agents are being actively investigated. Fluorouracil has a 10-15% response rate, and surgical excision of isolated metastases should always be considered. Therapy for metastatic renal cancer remains inadequate, but recent developments in basic and clinical research suggest future improvement.

Prognostic factors of renal cell carcinoma: a multivariate analysis

BACKGROUND AND OBJECTIVES

To establish appropriate therapeutic modalities for renal cell carcinoma (RCC), informations on the factors affecting prognosis of patients are essential. For this purpose, multivariate analysis including a large set of variables is necessary.

METHODS

Prognostic significance of 14 clinical factors and 19 histologic factors including counting of silver-stained nucleolar organizer regions (AgNORs) were evaluated in 96 patients. Age of patients ranged from 41 to 85 (median 59) yr with a male to female ratio of 4:1. The tumors were staged based on the TNM classification as follows: 7 in stage I, 58 in stage II, 15 in stage III, and 11 in stage IV.

RESULTS

The overall and metastasis-free survival rates in all patients were 80.1% and 72.7%, respectively. Multivariate analysis using Cox's proportional hazards model performed on the factors proved to be significant at the univariate analysis. Univariate analysis revealed four clinical factors including presence of macroscopic hematuria, symptoms such as pain and palpable abdominal mass, anemia, and adjuvant therapy, and nine histologic factors, including AgNOR count, to be significant for survival. Multivariate analysis showed that anemia, pathological stage, and AgNOR count were independent factors for overall survival of patients. The AgNOR count, in particular, is the only predictive factor for metastasis-free survival.

CONCLUSIONS

Among various clinicopathological factors, anemia, pathological stage, and AgNOR count are significant prognosticators of RCC. The AgNOR count is also predictive factor for metastasis-free survival.

Molecular analysis of occupational cancer: infrequent p53 and ras mutations in renal-cell cancer in workers exposed to gasoline

Occupational exposure to gasoline has been identified in several studies as a risk factor for renal-cell cancer. Cases of renal-cell cancer with and without work-related exposure to gasoline or gasoline and diesel fuel were studied for the presence of mutations in the tumour-suppressor gene p53 (n = 23 exposed and 30 non-exposed cases studied) and ras oncogene (n = 30 exposed and 36 non-exposed cases studied). An average cumulative exposure was estimated at 10 ppm-years benzene among the exposed. Three p53 mutations were detected by denaturing-gradient gel electrophoresis (DGGE) among the 23 exposed cases (3/23, 13%). Of the non-exposed referent cases, 4 had a mutation (4/30, 13%). All but one of the cases with a p53 mutation had smoked. A ras gene (K-ras or N-ras) mutation was found in 3 (3/66, 4.5%) cases, all of whom were smoker referents. We conclude that p53 and ras mutations are infrequent in renal-cell cancer associated with occupational exposure to gasoline. However, the majority of the mutations (6/7 for p53, and 3/3 for ras genes) were seen in smokers.

Epidermal growth factor receptor expression is associated with rapid tumor cell proliferation in renal cell carcinoma

Epidermal growth factor receptor (EGF-r) expression and tumor cell proliferation rate have been proposed as potential prognostic parameters in renal cell carcinoma (RCC). In this study, immunohistochemical stains using antibodies to EGF-r and the cell proliferation marker Ki-67 (MIB-1) were used to study the relationship between EGF-r expression, tumor cell proliferation, and prognosis in 50 non-papillary RCC extending beyond the renal capsule (pT3). A high Ki-67 labeling index (LI) was associated with poor patient prognosis (P < .05). Thirty-eight cases (76%) expressed strong cell membrane immunoreactivity for EGF-r. There was a tendency toward a shortened survival for EGF-r-positive tumors (P = .08). Tumor growth fraction (Ki-67 LI) was significantly higher in EGF-r-positive tumors than in EGF-r-negative tumors (P < .05), suggesting that rapid tumor proliferation might be responsible for the poor prognosis associated with EGF-r-positive RCC.

Renal cell carcinoma

Renal cell carcinoma (RCC) is characterized by (a) lack of early warning signs, which results in a high proportion of patients with metastases at the time of diagnosis; (b) protean clinical manifestations; and (c) resistance to radiotherapy and chemotherapy. The estimates of new diagnoses and deaths from kidney cancer in the United States during 1996 are 30,600 and 12,000, respectively. RCC occurs nearly twice as often in men as in women. The age at diagnosis is generally older than 40 years; the median age is in the midsixties. The incidence of RCC has been rising steadily. Between 1974 and 1990, there was a 38% increase in the number of patients who had a diagnosis of RCC. This increase was accompanied by a significant improvement in 5-year survival. Both trends are likely the result of improved diagnostic capability. Newer radiographic techniques, including ultrasonography, computed tomography, and magnetic resonance imaging, are detecting kidney tumors more frequently and at a lower disease stage, when tumors can be resected for cure. Surgical treatment is the only curative therapy for localized RCC. Radical nephrectomy remains the mainstay of surgical management, but techniques are being modified. These modifications include partial nephrectomy and resection of vena caval thrombi. In highly selected cases, surgical resection of locally recurrent RCC or of disease at a solitary metastatic site is associated with long-term survival. Metastatic RCC is highly resistant to the many systemic therapies that have been extensively investigated. A minority of patients achieve complete or partial response to interferon, interleukin-2, or both. Response can be dramatic but is rarely durable. Because most patients do not achieve response, these agents are not considered effective treatments for RCC, but the response in some patients indicates the need for continued research on their use. Identification of new agents with better antitumor activity against metastases remains a high priority in clinical investigation of therapy for this refractory disease.

Biological prognostic factors in renal cell carcinoma

– The authors have reviewed literature regarding the main contributions of molecular biology to renal cell carcinoma characterisation. The progress made in the analysis of chromosomal alterations, oncogenes, p53 protein, proliferation indices and adhesion molecules are described. The authors conclude that molecular biology, especially the analysis of chromosomal alterations and proliferation indices, may contribute to renal cell carcinoma diagnosis and to the understanding of its pathogenesis and prognosis.