Adjuvant therapy in renal cell carcinoma: does higher risk for recurrence improve the chance for success?

The success of targeted therapies, including inhibitors of the vascular endothelial growth factor pathway or the mammalian target of rapamycin, in the treatment of metastatic renal cell carcinoma led to interest in testing their efficacy in the adjuvant setting. Results from the first trials are now available, with other studies due to report imminently. This review provides an overview of adjuvant targeted therapy in renal cell carcinoma, including interpretation of currently available conflicting data and future direction of research. We discuss the key differences between the completed targeted therapy adjuvant trials, and highlight the importance of accurately identifying patients who are likely to benefit from adjuvant treatment. We also consider reasons why blinded independent radiology review and treatment dose may prove critical for adjuvant treatment success. The implications of using disease-free survival as a surrogate end point for overall survival from the patient perspective and measurement of health benefit have recently been brought into focus and are discussed. Finally, we discuss how the ongoing adjuvant trials with targeted therapies and checkpoint inhibitors may improve our understanding and ability to prevent tumor recurrence after nephrectomy in the future.

Integrating cytokines and angiogenic factors and tumour bulk with selected clinical criteria improves determination of prognosis in advanced renal cell carcinoma.

BACKGROUND: In two clinical trials of the vascular endothelial growth factor (VEGF) receptor inhibitor pazopanib in advanced renal cell carcinoma (mRCC), we found interleukin-6 as predictive of pazopanib benefit. We evaluated the prognostic significance of candidate cytokines and angiogenic factors (CAFs) identified in that work relative to accepted clinical parameters. METHODS: Seven preselected plasma CAFs (interleukin-6, interleukin-8, osteopontin, VEGF, hepatocyte growth factor, tissue inhibitor of metalloproteinases (TIMP-1), and E-selectin) were measured using multiplex ELISA in plasma collected pretreatment from 343 mRCC patients participating in the phase 3 registration trial of pazopanib vs placebo (NCT00334282). Tumour burden (per sum of longest diameters (SLD)) and 10 other clinical factors were also analysed for association with overall survival (OS; based on initial treatment assignment). RESULTS: Osteopontin, interleukin-6, and TIMP-1 were independently associated with OS in multivariable analysis. A model combining the three CAFs and five clinical variables (including SLD) had higher prognostic accuracy than the International Metastatic Renal Cell Carcinoma Database Consortium criteria (concordance-index 0.75 vs 0.67, respectively), and distinguished two groups of patients within the original intermediate risk category. CONCLUSIONS: A prognostic model incorporating osteopontin, interleukin-6, TIMP-1, tumour burden, and selected clinical criteria increased prognostic accuracy for OS determination in mRCC patients.

Assessment of progression-free survival as a surrogate end-point for overall survival in patients with metastatic renal cell carcinoma.

BACKGROUND: To determine suitability of progression-free survival (PFS) as a surrogate end-point for overall survival (OS), we evaluated the relationship between PFS and OS in 750 treatment-naïve metastatic renal cell carcinoma (mRCC) patients who received sunitinib or interferon-alpha (IFN-α) in a phase III study. METHODS: The relationship between PFS and post-progression survival (PPS; the difference between PFS and OS) was studied, which correctly removes inherent dependencies between PFS and OS, to properly estimate whether and to what extent PFS can serve as a surrogate for OS. A Weibull parametric model to failure time data was fit to determine whether longer PFS was significantly and meaningfully predictive of longer PPS. In a sensitivity analysis by Kaplan-Meier non-parametric method, PPS curves for three approximately equal numbered groups of patients categorised by PFS were compared by log-rank test. RESULTS: In the Weibull parametric model, longer PFS was significantly predictive of longer PPS (P<0.001). The model also allowed prediction of estimated median PPS duration from actual PFS times. In the Kaplan-Meier (non-parametric) analysis, incrementally longer PFS was also associated with longer PPS, and the PPS curves for the three PFS groups were significantly different (P<0.0001). CONCLUSIONS: A positive relationship was found between PFS and PPS duration in individual mRCC patients randomised to first-line treatment with sunitinib or IFN-α. These results indicate that PFS can act as a surrogate end-point for OS in the first-line mRCC setting and provide clinical researchers with a potentially useful approach to estimate median PPS based on PFS.

Efficacy and safety of sunitinib in elderly patients with metastatic renal cell carcinoma.

BACKGROUND: We retrospectively analyzed sunitinib outcome as a function of age in metastatic renal cell carcinoma (mRCC) patients. METHODS: Data were pooled from 1059 patients in six trials. Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS) were compared by log-rank test between patients aged <70 (n=857; 81%) and ≥70 (n=202; 19%) years. RESULTS: In first-line patients, median PFS was comparable in younger and older patients, 9.9 vs 11.0 months, respectively (HR, 0.89; 95% CI: 0.73-1.09; P=0.2629), as was median OS, 23.6 vs 25.6 months (HR, 0.93; 95% CI: 0.74-1.18; P=0.5442). Similarly, in cytokine-refractory patients, median PFS was 8.1 vs 8.4 months (HR, 0.79; 95% CI: 0.49-1.28; P=0.3350), while median OS was 20.2 vs 15.8 months (HR, 1.14; 95% CI: 0.73-1.79; P=0.5657). Some treatment-emergent adverse events were significantly less common in younger vs older patients, including fatigue (60% vs 69%), cough (20% vs 29%), peripheral edema (17% vs 27%), anemia (18% vs 25%), decreased appetite (13% vs 29%), and thrombocytopenia (16% vs 25%; all P<0.05). Hand-foot syndrome was more common in younger patients (32% vs 24%). CONCLUSIONS: Advanced age should not be a deterrent to sunitinib therapy and elderly patients may achieve additional clinical benefit.

Q-TWiST analysis to estimate overall benefit for patients with metastatic renal cell carcinoma treated in a phase III trial of sunitinib vs interferon-α.

BACKGROUND: In a randomised phase III trial of treatment-naive patients with metastatic renal cell carcinoma, sunitinib showed significant improvement in progression-free survival (PFS) compared with interferon (IFN)-α. We assessed between-treatment differences in overall benefit using a quality-adjusted Time Without Symptoms of disease progression or Toxicity of treatment (TWiST; Gelber and Goldhirsch) analysis. METHODS: In this analysis, in which only grade 3/4 treatment-related toxicities were included, overall survival was partitioned into three health states: toxicity (time with toxicity after randomisation and before progression), time without symptoms of disease progression or toxicity, and time from progression until death. Between-treatment differences in the mean duration of each state were calculated. A threshold utility analysis was used to assess quality-adjusted TWiST (Q-TWiST) outcomes. RESULTS: Q-TWiST scores showed that quality-adjusted survival time was greater with sunitinib than with IFN-α, even though certain grade 3/4 toxicities occurred more frequently with sunitinib. For both treatments, the mean number of days with toxicity was small compared with PFS. This effect was more pronounced with sunitinib in which time spent without progression or toxicity was 151 days greater than with IFN-α. CONCLUSION: Patients randomised to sunitinib had longer clinical benefit, defined as Q-TWiST scores, than patients randomised to IFN-α.

Everolimus in metastatic renal cell carcinoma patients intolerant to previous VEGFr-TKI therapy: a RECORD-1 subgroup analysis.

BACKGROUND: A relevant percentage of patients with metastatic renal cell carcinoma develop intolerance to vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFr-TKIs) and require careful selection of subsequent treatment. This retrospective analysis evaluated the safety and efficacy of everolimus in patients enrolled in the phase-III RECORD-1 trial who discontinued previous VEGFr-TKI therapy because of toxicity. METHODS: Patients with an adverse event (AE) as their primary reason for discontinuation of previous VEGFr-TKI therapy were included. Median progression-free survival (PFS) for VEGFr-TKI-intolerant patients in each arm was estimated using the Kaplan-Meier method, and effect on PFS (hazard ratio (HR)) was calculated using the Cox proportional hazard model. RESULTS: In VEGFr-TKI-intolerant patients (n=58, 14%), median PFS was 5.4 months with everolimus and 1.9 months with placebo (HR: 0.32; P=0.004). In sunitinib-intolerant patients (n=26), median PFS was 5.1 months with everolimus and 2.8 months with placebo (HR: 0.28; P=0.033). Grade 3/4 AEs reported with everolimus in VEGFr-TKI-intolerant patients included infections (16%), fatigue (7%) and stomatitis (4%). The toxicity profile of everolimus was similar in the VEGFr-TKI-intolerant and overall study populations. CONCLUSION: Everolimus is well tolerated and efficacious with no increased toxicity in patients intolerant to VEGFr-TKI therapy.

Everolimus in metastatic renal cell carcinoma: Subgroup analysis of patients with 1 or 2 previous vascular endothelial growth factor receptor-tyrosine kinase inhibitor therapies enrolled in the phase III RECORD-1 study.

INTRODUCTION: In the phase III RECORD-1 trial (ClinicalTrials.gov: NCT00410124), patients with metastatic renal cell carcinoma (mRCC) who progressed on previous vascular endothelial growth factor receptor-tyrosine kinase inhibitor (VEGFr-TKI) therapy were randomised 2:1 to everolimus 10mg once daily (n=277) or placebo (n=139). Median progression-free survival (PFS) was 4.9months with everolimus and 1.9months with placebo (hazard ratio [HR], 0.33; P<.001). This preplanned, prospective sub-analysis evaluated PFS benefit of everolimus versus placebo in patients who had previously received 1 or 2 VEGFr-TKIs. PATIENTS AND METHODS: Median PFS was estimated using the Kaplan-Meier method, and Cox proportional hazards model was used to analyse differences in PFS. RESULTS: All patients (100%) received ⩾1 previous VEGFr-TKI; 26% of patients received 2 previous VEGFr-TKIs. Among patients who received 1 previous VEGFr-TKI, median PFS was 5.4months with everolimus and 1.9months with placebo (HR, 0.32; 95%confidence interval [CI], 0.24-0.43; P<.001). Among patients who received 2 previous VEGFr-TKIs, median PFS was 4.0months with everolimus and 1.8months with placebo (HR, 0.32; 95%CI, 0.19-0.54; P<.001). The everolimus safety profile was similar for both groups. CONCLUSIONS: Everolimus was associated with prolonged PFS relative to placebo in patients who received 1 or 2 previous VEGFr-TKIs. Patients who received only 1 previous VEGFr-TKI had apparently longer PFS with everolimus in reference to those who received 2 previous VEGFr-TKIs. These results support the use of everolimus as the standard of care in patients who fail initial VEGFr-TKI therapy.

Prognostic factors for progression-free and overall survival with sunitinib targeted therapy and with cytokine as first-line therapy in patients with metastatic renal cell carcinoma.

BACKGROUND: Analysis of prognostic factors for progression-free survival (PFS) and overall survival (OS) was performed using final data from a randomized phase III trial of sunitinib versus interferon-α (IFN-α) as first-line metastatic renal cell carcinoma (RCC) therapy. DESIGN: A multivariate Cox regression model analyzed baseline variables for prognostic significance. Each variable was investigated univariately and then multivariately using a stepwise algorithm. RESULTS: Each treatment arm comprised 375 patients. For sunitinib, multivariate analysis of PFS identified five independent predictors, including serum lactate dehydrogenase (LDH) level, presence of ≥2 metastatic sites, no prior nephrectomy, Eastern Cooperative Oncology Group (ECOG) performance status, and baseline platelet count, while multivariate analysis of OS identified serum LDH level, corrected serum calcium level, time from diagnosis to treatment, hemoglobin level, ECOG performance status, and presence of bone metastasis as predictors. For IFN-α, LDH level and presence of ≥2 metastatic sites were common predictors of PFS to those for sunitinib, as were all predictors of OS except ECOG status. CONCLUSIONS: This analysis identified prognostic factors for PFS and OS with sunitinib as first-line metastatic RCC therapy and confirmed that the Memorial Sloan-Kettering Cancer Center model is applicable in the era of targeted therapy.

Concomitant renal cell carcinoma and chronic myelogenous leukemia: use of a targeted approach.

Numerous therapeutic options have been introduced for metastatic renal cell carcinoma (MRCC) in recent years, including monoclonal antibodies such as bevacizumab and small-molecule tyrosine kinase inhibitors such as sunitinib and sorafenib. Similarly, several other small-molecule inhibitors-including imatinib, dasatinib, and nilotinib-have been approved for the treatment of chronic myelogenous leukemia (CML). The combination of these targeted agents is an area of intense clinical investigation. Here, we describe a patient diagnosed with MRCC)while on imatinib therapy for cml. Treatment of this patient with the combination of bevacizumab and imatinib led to a 6-month period of stable disease, with no treatment-related adverse events. More extensive clinical exploration of this combination of agents may therefore be warranted.

Combined cytoreductive laser therapy and immunotherapy for palliation of metastatic renal cell carcinoma to the head and neck.

Interleukin-2 (IL-2) remains the mainstay of treatment for metastatic renal cell carcinoma (RCC), but minimally invasive surgical techniques have provided new options for the combined treatment of RCC. Two patients with metastatic RCC to the head and neck treated by combined laser-induced thermal therapy and IL-2 were described in this case report. Both patients had an extended survival compared to the historical survival of 10 months for metastatic RCC but eventually succumbed to progressive disease. The authors' initial experience with metastatic RCC suggests that laser thermoablation and immunotherapy in selected patients with metastatic RCC is warranted as a palliative treatment, but a larger study with long-term follow-up is necessary to determine the effectiveness of this approach.

Joint association of polymorphism of the FGFR4 gene and mutation TP53 gene with bladder cancer prognosis.

The impact of the fibroblast growth factor receptor 4 (FGFR4) Gly388Arg polymorphism on bladder cancer is unknown. We found no clear correlations between the FGFR4 genotype and risk of bladder cancer or pathological parameters. Neither the polymorphism nor TP53 mutation status was an independent predictor of prognosis, but they might act jointly on the disease-specific survival of patients.

Reevaluation of the 1997 TNM classification for renal cell carcinoma: T1 and T2 cutoff point at 4.5 rather than 7 cm. better correlates with clinical outcome.

PURPOSE: We analyzed the effects of the change in TNM classification from the 1987 to the 1997 version and suggest a modified tumor size cutoff point between T stages 1 and 2 for renal cell carcinoma. MATERIALS AND METHODS: We evaluated a database containing the records of 661 patients who underwent nephrectomy between 1989 and 1999. The effect of the change in TNM classification on the distribution of patients between stages, the rates of M+ and N+ disease, and the local and distant recurrence rates were outlined for 280 patients with T stages 1 and 2 disease. The Cox model was used to identify the optimal cutoff point between T1 and T2 disease, and the resulting effect of adopting this cutoff was outlined. RESULTS: A total of 174 and 128 cases were down staged from 1987 version stage T2 to 1997 version stage T1 and from 1987 TNM stage II to 1997 TNM stage I, respectively. Survival was not significantly different in patients with 1997 TNM stages I and II disease due to a lack of survival difference during the first 2 years of followup. Stage shift also caused an increase in average tumor size, the proportion of patients with high grade cancer, and M+ and N+ disease at diagnosis in 1997 stages T1 and T2 as well as an increase in the proportion of 1997 stage T2N0M0 cases at diagnosis with systemic failure. Analysis of 11 potential cutoff points between 1 and 10 cm. revealed that 4.5 cm. was most predictive of patients survival (hazards ratio 4.99, p = 0.0001). Using this cutoff resulted in improved discriminatory power of the TNM classification and a moderating effect on the distribution of patients, average tumor size, high grade disease, M+ and N+ disease at diagnosis, and systemic failure between T(14.5) and T(24.5) compared with 1997 T1 and T2. CONCLUSIONS: Our data imply that the current cutoff point of 7 cm. between stages T1 and T2 tumors is too high. Lowering the cutoff to 4.5 cm. resulted in better discriminatory power of the TNM classification in our dataset. This observation should be further validated by external data.

Vaccine and gene therapy of renal cell carcinoma.

The concept of tumor vaccines is not new. However, advances in gene transfer technology, tumor immunology, molecular biology, and methods of monitoring antitumor response, have allowed for novel, more specific vaccine approaches. For example, first-generation tumor vaccines were composed of whole inactivated cancer cells, or tumor lysates (Tuly) given together with immune adjuvants like bacillus Calmette-Guerin (BCG). Current strategies include tumor cells modified with genes encoding molecules necessary to stimulate a cytotoxic T cell response, such as cytokine genes, foreign HLA genes, tumor-associated antigen (TAA) genes, and even costimulatory molecules. Activation of cellular immunity requires at least three synergistic signals including presentation of specific tumor antigens, costimulatory signals (B7 molecules), and propagation of the immune response via cytokine release. In general, tumor cells often fail to demonstrate any of these immunostimulatory properties. Dendritic cell-based vaccines are gaining popularity as these cells can properly present TAA to the immune system, thus circumventing the poor antigen-presenting qualities of tumor cells. Dendritic cells can be "loaded" with TAA or other molecules either by their natural endocytotic capabilities, or by genetic modification.

Multi-institutional phase I/II trial of oral bexarotene in combination with cisplatin and vinorelbine in previously untreated patients with advanced non-small-cell lung cancer.

PURPOSE: Bexarotene (Targretin; Ligand Pharmaceuticals, Inc, San Diego, CA) is a retinoid-X-receptor (RXR)-selective retinoid with preclinical antitumor activity in squamous cell cancers. In this phase I/II trial, we combined bexarotene with cisplatin and vinorelbine in the treatment of patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Forty-three patients who had stage IIIB NSCLC with pleural effusion or stage IV NSCLC and had received no prior therapy received bexarotene in combination with cisplatin (100 mg/m2) and vinorelbine (alternating doses of 30 mg/m2 and 15 mg/m2). In the phase I portion, the daily dose of bexarotene was escalated in cohorts of three patients from 150 mg/m2 to 600 mg/m2, beginning 1 week before the start of the cisplatin-vinorelbine regimen. Once the maximum-tolerated dose (MTD) of bexarotene was determined, the study entered the phase II portion. Response rate was the primary end point; median survival time and 1-year survival rate were secondary end points. RESULTS: In the phase I portion, the daily MTD of bexarotene was determined to be 400 mg/m2. Eight of 43 patients exhibited major responses. Seven (25%) of the 28 patients in the phase II portion responded to treatment. The median survival time in the phase II portion was 14 months; nine (32%) of the 28 patients were still alive at a minimum follow-up of 2 years. One-year and projected 3-year survival rates were 61% and 30%, respectively. The most common grade 3 and 4 adverse events were hyperlipemia, leukopenia, nausea, vomiting, pneumonia, dyspnea, anemia, and asthenia. Grade 3 and 4 laboratory abnormalities with incidences greater than 5% were decreased hemoglobin levels and WBC, absolute neutrophil, and absolute lymphocyte counts and increased prothrombin time and creatinine and amylase levels. Of the two cases of pancreatitis, one required hospitalization and both were associated with increased triglyceride levels. There was one death secondary to renal insufficiency unrelated to bexarotene treatment. CONCLUSION: In patients with advanced NSCLC, bexarotene with cisplatin and vinorelbine yielded acceptable phase II response rates (25%) and was associated with better-than-expected survival (14-month median survival time; 61% 1-year, 32% 2-year, and 30% projected 3-year survival rates). The regimen should be studied in larger clinical trials.

Treatment of metastatic renal cell carcinoma with high-dose bolus interleukin-2 in a non-intensive care unit: an analysis of 124 consecutively treated patients.

PURPOSE: In prior studies of high-dose interleukin-2 (IL-2) therapy in the treatment of metastatic renal cell carcinoma, the majority of patients were asymptomatic (65% of patients had Eastern Cooperative Oncology Group [ECOG] scores of 0 [no cancer-related symptoms]). These studies demonstrated that an ECOG score of 0 predicted an objective antitumor response to IL-2 (P = 0.03). The current study determined the response frequency to high-dose IL-2 therapy in a primarily symptomatic patient population (ECOG = 1 [presence of cancer-related symptoms] for 57.3% of patients). The IL-2 therapy was administered in a non-intensive care unit (non-ICU). PATIENTS AND METHODS: In this single-institution study of high-dose IL-2 therapy, 124 patients were consecutively enrolled and treated with the drug. Antitumor responses and safety were assessed by radiographic methods and the occurrence of grade 3 and 4 adverse events, respectively. RESULTS: The frequency of objective responses was 14.5% (18 of 124 patients). Seven patients (5.6%) and 11 patients (8.9%) experienced complete responses (CRs) and partial responses (PRs), respectively. Two of 7 patients (28.6%) with CR and 7 of 11 patients (63.6%) with PR had ECOG scores of 1. The median response duration is 18 months for all responders (CR plus PR). The median survival duration is 15 months for all patients. It was not possible to estimate the median survival duration for all responders because the majority of responding patients were alive at close of study. All patients with CR and 5 patients with PR were alive at close of study. The frequency of grade 3 and 4 adverse events was comparable to or less than published data and IL-2 was safely administered in a non-intensive care unit. CONCLUSION: The frequency of objective antitumor responses in patients with ECOG scores of 1 suggests that high-dose IL-2 therapy may have comparable effectiveness in symptomatic and asymptomatic patients. High-dose IL-2 can be administered in a non-ICU setting with acceptable toxicity and the chance of clinical benefit.

Improved prognostication of renal cell carcinoma using an integrated staging system.

PURPOSE: To integrate stage, grade, and Eastern Cooperative Oncology Group (ECOG) performance status (PS) into a clinically useful tool capable of stratifying the survival of renal cell carcinoma (RCC) patients. PATIENTS AND METHODS: The medical records of 661 patients undergoing nephrectomy at University of California Los Angeles between 1989 and 1999 were evaluated. Median age was 61 years, male-to-female ratio was 2.2:1, and median follow-up was 37 months. Survival time was the primary end point assessed. Sixty-four possible combinations of stage, grade, and ECOG PS were analyzed and collapsed into distinct groups. The internal validity of the categorized was challenged by a univariate analysis and a multivariate analysis testing for the accountability of each UCLA Integrated Staging System (UISS) category against independent variables shown to have impact on survival. RESULTS: Combining and stratifying 1997 tumor-node-metastasis stage, Fuhrman's grade and ECOG PS resulted in five survival stratification groups designated UISS, and numbered I to V. The projected 2- and 5-year survival for the UISS groups are as follows for the groups: I, 96% and 94%; II, 89% and 67%; III, 66% and 39%; IV, 42% and 23%; and V, 9% and 0%, respectively. UISS accounted for the significant variables in the variate analysis. CONCLUSION: A novel system for staging and predicting survival for RCC integrating clinical variables is offered. UISS is simple to use and is superior to stage alone in differentiating patients' survival. Our data suggests that UISS is an important prognostic tool for counseling patients with various stages of kidney cancer. Further prospective large-scale validation with external data is awaited.

Measuring the incremental cost of clinical cancer research.

PURPOSE: To summarize evidence on the costs of treating patients in clinical trials and to describe the Cost of Cancer Treatment Study, an ongoing effort to produce generalizable estimates of the incremental costs of government-sponsored cancer trials. METHODS: A retrospective study of costs will be conducted with 1,500 cancer patients recruited from a randomly selected sample of institutions in the United States. Patients accrued to either phase II or phase III National Cancer Institute-sponsored clinical trials during a 15-month period will be asked to participate in a study of their health care utilization (n = 750). Costs will be measured approximately 1 year after their trial enrollment from a combination of billing records, medical records, and an in-person survey questionnaire. Similar data will be collected for a comparable group of cancer patients not in trials (n = 750) to provide an estimate of the incremental cost. RESULTS: Evidence suggests insurers limit access to trials because of cost concerns. Public and private efforts are underway to change these policies, but their permanent status is unclear. Previous studies found that treatment costs in clinical trials are similar to costs of standard therapy. However, it is difficult to generalize from these studies because of the unique practice settings, insufficient sample sizes, and the exclusion of potentially important costs. CONCLUSION: Denials of coverage for treatment in a clinical trial limit patient access to trials and could impede clinical research. Preliminary estimates suggest changes to these policies would not be expensive, but these results are not generalizable. The Cost of Cancer Treatment Study is an ongoing effort to provide generalizable estimates of the incremental treatment cost of phase II and phase III cancer trials. The results should be of great interest to insurers and the research community as they consider permanent ways to finance cancer trials.

Dendritic cell-based immunotherapy of renal cell carcinoma.

Although mostly resistant to cytotoxic therapy, renal cell carcinoma has been a testing ground for immunotherapy. The approval of interleukin-2 for the treatment of renal cell carcinoma was a landmark "proof of principle" which showed that agents working solely via the immune system can cause durable cancer remission. Dendritic cells are central to immune-mediated surveillance and destruction of abnormal cells. They possess all the components required to educate immune effector cells that can then mediate tumor destruction. In vitro strategies to expand and load dendritic cells with antigens have now led to human vaccine trials in renal cell carcinoma and other malignancies.