Enhanced orotate phosphoribosyltransferase activity in renal cell carcinoma and its prognostic significance

15590

Background: 5-Fluorouracil ( 5-FU ) is an anticancer agent clinically used against various cancers including renal cell carcinoma ( RCC ). 5-FU is a prodrug and orotate phosphoribosyltransferase ( OPRT ) is the principal enzyme which directly converts 5-FU to an active anticancer metabolite, 5-fluoro-2’-deoxyuridine 5’-monophosphate. Furthermore, OPRT is the key enzyme in the de novo DNA and RNA synthetic process, which converts orotic acid to orotidine 5’-phosphate. Little is known about the significance of OPRT in a variety of cancers including RCC. We investigated OPRT activity in 83 RCC and evaluated the association between OPRT activity and the stage/grade of RCC. The relationship between OPRT activity in RCC cells and their sensitivity to 5-FU was also examined. Methods: OPRT activity in non-fixed fresh frozen RCC and normal kidney were determined enzymatically by the 5-FU phosphorylation assay. The sensitivity of RCC cells to 5-FU was assessed by the microculture tetrazolium dye assay. Results: OPRT activity was approximately 8.5-fold higher in RCC compared to normal kidney. OPRT activity in T3/4 RCC was 3-fold higher than that in T1/2 RCC. OPRT activity in M1 RCC was 2.5-fold higher than that in M0 RCC. In addition, OPRT activity in Stage III/IV RCC was 3-fold higher than that in Stage I/II RCC. The level of OPRT activity in Grade 3 RCC was 3-fold higher than that in Grade 1/2 cancer. Patients with RCC with low OPRT activity had a longer postoperative disease-specific survival than those with high activity in the 5-year follow-up. OPRT activity in RCC cells positively correlated with their sensitivity to 5-FU. Conclusions: The present study has demonstrated that OPRT activity in RCC was higher than that in normal kidney, and that OPRT activity positively correlated with the stage/grade of RCC. Moreover, higher OPRT activity in RCC predicted worse prognosis and higher sensitivity to 5-FU. These results suggest that OPRT activity may be used as both a prognostic parameter and a predictive indicator for 5-FU efficacy in RCC.

No significant financial relationships to disclose.

Diabetes mellitus and kidney cancer risk: The results of Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study)

BACKGROUND

Diabetes mellitus (DM) is reported as being a risk factor associated with kidney cancer in Western countries. The incidence of both kidney cancer and DM is lower in Japan than the other developed countries, albeit on the rise.

METHODS

We evaluated the risk factors for kidney cancer mortality using the database of the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC) study. The analytic cohort included 46 462 males and 64 326 females aged 40-79 years old. The Cox proportional hazards model was used to determine age- and sex-adjusted relative risk and its 95% confidence intervals.

RESULTS

DM showed an increased, age- and sex-adjusted hazard ratio for kidney cancer mortality, but it failed to achieve statistical significance after controlling for other factors.

CONCLUSION

The present study showed that DM increased the risk of kidney cancer death among the Japanese population. However, further studies may be needed to confirm the findings in the present study because DM failed to remain as a significant risk factor after controlling for other factors because of the small number of kidney cancer deaths in the present study.

Overexpression of XIAP expression in renal cell carcinoma predicts a worse prognosis

X-linked inhibitor of apoptosis protein (XIAP) is the most potent caspase-inhibitory IAP family member and a negative regulator of various apoptotic stimuli. Thus, XIAP overexpression in cancer cells may select for tumor cell survival following various cytotoxic therapeutic modalities. The anatomical staging system in renal cell carcinoma (RCC) currently provides good prognostic information, albeit insufficient. We hypothesize that overexpression of XIAP in RCC may serve as a molecular prognostic marker in RCC and improve the staging of RCC. This study examined the protein level of XIAP in lysates from surgical specimens of 109 patients with RCC and 109 normal kidney specimens from the same patients. The level of XIAP expression was quantified by Western blot analysis using non-fixed fresh frozen tissues of RCCs and normal kidneys. Results indicated that the mean level of XIAP expression was higher in RCC compared to autologous normal kidney, and the XIAP expression level in 38/109 (35%) of RCC was more than 2-fold greater than that in normal kidney tissue. In Stage I/II RCC, the mean XIAP expression level was almost identical to that detected in normal kidney, whereas XIAP expression in Stage III/IV was 2.5-fold higher than that in Stage I/II RCC. Levels of XIAP expression also correlated with the grade of RCC. Patients with RCC with low XIAP expression had a longer postoperative disease-specific survival as compared to those with high expression in the 5-year follow-up. The suggested role of XIAP in the regulation of resistance in apoptosis was examined in vitro following treatment of RCC cell lines with XIAP antisense oligonucleotide and the cells were sensitized to both Fas-mediated and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. The present study demonstrates at the protein level that XIAP is overexpressed in RCC, and that high XIAP expression in RCC predicted a worse prognosis. In addition, XIAP antisense oligonucleotide sensitized RCC to Fas/TRAIL-induced apoptosis. These results suggest that XIAP expression in RCC may be used as a prognostic parameter, and that downregulation or inhibition of XIAP expression in RCC may reverse immune resistance.

The significance of the expression of dihydropyrimidine dehydrogenase in prostate cancer

OBJECTIVE

To measure dihydropyrimidine dehydrogenase (DPD), an enzyme involved in the metabolism of 5-fluorouracil (5-FU), expression in prostate cancer and determine whether 5-chloro-2,4-dihydroxypyridine (CDHP), a potent inhibitor of DPD, enhances the antitumoral activity of 5-FU against prostate cancer.

PATIENTS, MATERIALS AND METHODS

In all, 44 prostate tissue specimens were obtained from men who had a radical prostatectomy alone for prostate cancer, and 38 specimens from men who had had neoadjuvant hormonal therapy. We analysed the cancerous tissue and normal prostate tissue for DPD expression using immunohistochemistry, and determined its prognostic significance. In cultured human prostate cancer lines (DU145 and LNCaP), we compared the cytotoxicity of 5-FU/CDHP with that of 5-FU alone. Finally, in experiments on immunodeficient mice, we studied the effect of oral administration of tegafur, a pro-drug for 5-FU, with or without CDHP on the growth of tumours introduced by injection of DU145 cells.

RESULTS

The expression of DPD was significantly higher in cancerous than normal prostate tissue; 36 of 44 (82%) specimens of prostate cancer expressed DPD, whereas only 25 of 44 (57%) specimens of normal prostate tissue expressed DPD. For men with prostate cancer who had radical prostatectomy alone, men with negative DPD expression tended to have a longer recurrence-free survival than those with positive expression; there were no recurrences in men with prostate cancer and negative DPD expression in the 5-year follow-up. DPD expression was significantly lower in men with prostate cancer who received neoadjuvant hormonal therapy. In vitro treatment of human prostate cancer cell lines with 5-FU/CDHP showed more cytotoxicity than with 5-FU treatment alone. Finally, DU145 tumours in mice treated with tegafur and CDHP were significantly smaller than in mice given tegafur alone.

CONCLUSION

The present study showed that DPD expression is elevated in prostate cancer, and indicate that DPD inhibitors might enhance the antitumour activity of 5-FU against prostate cancer.

Prospective cohort study of the risk of prostate cancer among rotating-shift workers: findings from the Japan collaborative cohort study

Shift workers have been reported to have an increased risk of some cancers. However, the risk of prostate cancer in shift workers is not known to have been examined previously. This study prospectively examined the association between shift work and risk of prostate cancer incidence among 14,052 working men in Japan enrolled in a large-scale prospective cohort. A baseline survey was conducted between 1988 and 1990. Subjects were asked to indicate the most regular work schedule they had undertaken previously: day work, rotating-shift work, or fixed-night work. During 111,974 person-years, 31 cases of prostate cancer were recorded. The Cox proportional hazards model was used to estimate the risk, with adjustments for age, family history of prostate cancer, study area surveyed, body mass index, smoking, alcohol drinking, job type, physical activity at work, workplace, perceived stress, educational level, and marriage status. Compared with day workers, rotating-shift workers were significantly at risk for prostate cancer (relative risk = 3.0, 95% confidence interval: 1.2, 7.7), whereas fixed-night work was associated with a small and nonsignificant increase in risk. This report is the first known to reveal a significant relation between rotating-shift work and prostate cancer.

Less Vigorous Surgery for Second Primary Lung Cancer

BACKGROUND

Patients with second primary lung cancer (SPLC) have a heterogeneous background. The optimum modality of treatment for SPLC patients has not yet been determined. The objective of this study was to attempt to identify the value of less vigorous therapies such as segmentectomy or video-assisted thoracic surgery (VATS) in SPLC.

METHODS

We retrospectively reviewed the medical records of 46 patients who underwent resection for SPLC in Fukuoka University Hospital between January 1994 and April 2005. Patients were separated into two groups (LVT: less vigorous therapy including segmentectomy or VATS lobectomy; LCT: lobectomy with conventional thoracotomy). The characteristics of each group were evaluated and survival rates were analyzed at 5 years after surgery.

RESULTS

The mean amount of blood loss was found to be significantly different ( P = 0.0062) with 59.44 +/- 14.00 ml for LVT cases and 254.48 +/- 63.62 ml for LCT. None of the LVT patients experienced postoperative complications. The 5-year survival rate was 62.7 % for LVT and 57.7 % for LCT. There was no significant difference in survival rates between these groups.

CONCLUSIONS

Although differences were seen in the characteristics, less invasive surgery such as VATS or segmentectomy may be a feasible treatment for SPLC.

[Salvage chemotherapy with paclitaxel, ifosphamide and nedaplatin for relapsed or refractory germ cell cancer]

PURPOSE

Only 20-30% of patients with cisplatin refractory or relapsed germ cell cancer will remain continuously disease free with salvage chemotherapy. Paclitaxel is a potent anticancer agent against a variety of solid cancers. The present study investigated the chemotherapy with paclitaxel in combination with nedaplatin, which is a derivative of cisplatin, and ifosphamide as salvage chemotherapy for cisplatin refractory germ cell cancer.

MATERIAL AND METHODS

The combination chemotherapy consisted of paclitaxel 210 mg/m2 on day 1, nedaplatin 100 mg/m2 on day 2 and ifosphamide 1.2 g/m2 on day 2-day 6 every three weeks. Fourteen patients with cisplatin refractory germ cell cancer, ranging in age from 17 to 44 years were enrolled onto the study.

RESULTS

Fourteen patients were evaluated for response and toxicity. Patients received 1-14 cycles of the combination chemotherapy. The median duration of follow-up was 34 months (10-64 months). Response rate was 57.1% (CR / PR(m-):8 cases, NC:5 cases, PD:1 cases). Seven patients remain alive without disease. However, 5 patients died of the disease. All patients had grade 3 or 4 hematological toxicity.

CONCLUSION

This study demonstrates that the chemotherapy with paclitaxel in combination with nedaplatin and ifosphamide showed a significant anticancer activity for patients with cisplatin refractory or relapsed germ cell cancer. These findings suggest that the combination chemotherapy may be one of the options of salvage chemotherapy for cisplatin refractory or relapsed germ cell cancer.

Risk factors for kidney cancer in a Japanese population: findings from the JACC Study

BACKGROUND: The incidence of kidney cancer is high in Western and Northern Europe and North America, and low in Asia. Although the incidence of kidney cancer in Japan is lower than the rates in the other industrialized countries, there is no doubt that it is increasing.

METHODS: We evaluated the risk factors for kidney cancer death using the database of the Japan Collaborative Cohort (JACC) Study (i.e., medical history, anthropometry, and lifestyle including dietary habits). The analytic cohort included 47,997 males and 66,520 females aged 40 years and older. The Cox proportional hazards model was used to determine adjusted relative risks.

RESULTS: A total of 36 males and 12 females died from kidney cancer during the follow-up of 9.6 ± 2.6 years and 9.9 ± 2.2 years, respectively. A medical history of hypertension, a fondness for fatty food, and consumption of black tea were associated with an increased risk of kidney cancer death while an intake of taro, sweet potato and potato was associated with a decreased risk.

CONCLUSIONS: The present study showed four factors to be related to kidney cancer death. However, further studies may be needed to evaluate risk factors for kidney cancer death in Japan because the number of kidney cancer death in the present study was small.

Association of serum phytoestrogen concentration and dietary habits in a sample set of the JACC Study

BACKGROUND: Phytoestrogens may be associated with a reduced risk of hormone dependent neoplasms such as prostate and breast cancers. We tried to determine the validity of the association between serum phytoestrogen concentrations and dietary habits obtained from a food frequency questionnaire used in the Japan Collaborative Cohort Study (JACC Study) for Evaluation of Cancer Risk sponsored by the Ministry of Education, Science, Sports and Culture of Japan (Monbusho).

METHODS: The subjects were 151 male controls who were selected for a nested case-control study for evaluating prostate cancer risk as part of the JACC Study. Dietary habits were determined using a food frequency questionnaire at baseline, and the concentrations of genistein, daidzein, and equol in frozen-stored serum samples assayed in 2002 were compared.

RESULTS: Tofu intake showed a significant association with the serum concentrations of genistein and daidzein (Spearman’s correlation coefficients (r_s) =0.30 and 0.27, respectively), and miso soup showed a slight association with serum concentrations of these phytoestrogens. In contrast, serum concentrations of equol were not associated with dietary intake of tofu and miso soup. After adjustment for serum daidzein concentration, serum equol concentration was associated with the intake of foods containing fat, meat, and coffee, but not green tea.

CONCLUSIONS: Serum genistein and daidzein concentrations were significantly associated with dietary intake of tofu, and slightly with intake of miso soup. Consumption of fat, meat, and coffee may be associated with equol production by intestinal microflora in this sample set.

Spontaneous healing of chyle leakage after lymphangiography

We report a 34-year-old man with the complication of chylous ascites after retroperitoneal lymphadenectomy that was refractory to various conservative therapies. Because surgical treatment for chylous ascites was considered, lymphangiography was performed to identify the area of leakage of chyle, after which the chylous ascites spontaneously healed.

Application of Dye-Enhanced Laser Ablation for Liver Resection

BACKGROUND

Dye-enhanced laser ablation (DLA) using a low-power diode laser for indocyanine green (ICG)-stained tissue has proven its effectiveness in dye-enhanced laser photocoagulation of retinal vessels or endoscopic surgical mucosectomy. We have applied DLA in hepatectomy and described its histological distinction in comparison with the cavitron ultrasonic surgical aspirator (CUSA).

METHODS

A diode laser (UDL-60 Laser unit, Olympus, Tokyo, Japan) with 810 +/- 20 nm wavelength was employed for this study. The ICG dye (Diagnogreen, Daiichi Pharmaceutical, Tokyo, Japan) with a peak absorption wavelength at 800-810 nm was injected topically into the resection plane of the liver. The liver tissue was divided by touching the tip of the diode laser. Three different concentrations of ICG solution such as 2.0, 1.0 and 0.5 mg/ml were tested in the preliminary animal experiment. The use of a low-power diode laser at 10 W with an ICG concentration of 0.5 mg/ml was the appropriate combination for liver resection. In the clinical series, 27 hepatectomies were performed by DLA, and 10 with CUSA.

RESULTS

DLA demonstrated smooth cutting and good hemostasis in liver resection. Among the hepatectomy cases given DLA, no postoperative hemorrhage or bile leakage was noted. The postoperative hospital stay was significantly shorter in the DLA than the CUSA group. The cut surface of the liver was sealed microscopically with a layer of protein coagulum.

CONCLUSIONS

A layer of protein sealant on the cut surface of the liver contributes to the short postoperative hospital stay when using DLA.

Successful endoscopic hemostasis for gastric arterial bleeding due to invasion of malignant lymphoma

A 75-year-old male with malignant lymphoma (ML) accompanied with gastric lesion was treated with combination chemotherapy. The patient produced tarry stool on the 4^th d, and emergency gastroscopy showed arterial bleeding from the lesion. Hemostasis was achieved by injecting pure ethanol and using hemostatic clips. There is only one previous report on endoscopic hemostasis being effective for bleeding due to lymphoma. Since gastric bleeding causes significant mortality, endoscopic hemostasis should be considered as first-line treatment for ML patients who were treated with chemotherapy.

Serum carotenoids and other antioxidative substances associated with urothelial cancer risk in a nested case-control study in Japanese men

PURPOSE

We assayed whether high serum carotenoids and antioxidative substances decrease the risk of urothelial cancer in a case-control study nested in a community based cohort in Japan, that is the Japan Collaborative Cohort Study.

MATERIALS AND METHODS

Information on subject life-styles and serum were collected in 1988 to 1990 and subjects were followed as late as 1999. Individuals who had or died of urothelial cancer and controls were matched for study area, sex and age. Serum was stored at -80C and analyzed in 2003. Of 14,097 male and 25,662 female subjects 40 to 79 years old there were 42 cases, which were matched to 124 controls.

RESULTS

The OR for the highest to lowest tertile of serum concentration was 0.28 (95% CI 0.07 to 1.15, trend p = 0.08) for beta-carotene, 0.36 (95% CI 0.10 to 1.27, trend p = 0.10) for total carotenes and 0.31 (95% CI 0.09 to -1.09, trend p = 0.09) for total carotenoids after adjustment for smoking in addition to matching variables. High concentrations of tocopherols and xanthophylls slightly tended to decrease the risk of urothelial cancer. In contrast, serum retinol, oxidized low density lipoprotein and Cu/Zn-superoxide dismutase were not associated with urothelial cancer risk.

CONCLUSIONS

Our results suggest that high serum carotenoids may decrease the risk of urothelial cancer with carotenes more effective than xanthophylls.

Dietary habits and risk of urothelial cancer death in a large-scale cohort study (JACC Study) in Japan

In the present study, the associations of dietary habits with the risk of urothelial cancer death were evaluated taking into consideration sex, age, and smoking habits. The Japan Collaborative Cohort Study was established in 1988-1990 and consisted of 47,997 men and 66,520 women observed until the end of 1999. A self-administered food-frequency questionnaire was used as a baseline survey. Hazard ratios for dietary factors were calculated by Cox's proportional hazards model. During the observation period, 63 men and 25 women died of urothelial cancer. Increasing age, male gender, and history of smoking were all significantly associated with increased risk of urothelial cancer death. A high intake of milk and fruits other than oranges reduced the risk significantly and dose dependently, in particular among subjects with smoking history. However, consumption of butter and yogurt had no associations with the risk. Intakes of cabbage, lettuce, green leafy vegetables, carrots, squash, tomatoes, and oranges were not significantly associated with the risk. It was suggested that urothelial cancer death could be potentially preventable by smoking cessation and regular intake of milk and fruit.

Dietary Habits and Risk of Urothelial Cancer Incidence in the JACC Study

BACKGROUND: The relationships between dietary habits and urothelial cancer have been discussed in many epidemiologic studies, however, they have not been sufficiently elucidated. In the present study, the associations of dietary habits with the risk of urothelial cancer incidence were evaluated taking into consideration sex, age, and smoking habits.

METHODS: The Japan Collaborative Cohort Study (JACC Study) was planned in the late 1980s as a large-scale cohort study surveying people comprehensively and detailing their lifestyles, and the study subjects were followed up until the end of 1997. Among the total of 110,792 participants, 26,464 men and 38,720 women were in areas where incident cases with cancer were identified. During the observation period, 95 men and 28 women suffered from urothelial cancer. Hazard ratios for dietary factors were calculated by Cox’s proportional hazards model.

RESULTS: Increasing age, male gender, and smoking history were all significantly associated with the risk of urothelial cancer. High consumption of pork was significantly associated with the risk. In contrast, high intakes of milk and fresh fish were significantly inversely associated with the risk. High intakes of Chinese cabbage and fruits were also significantly inversely associated with the risk of urothelial cancer.

CONCLUSIONS: It is suggested that high intakes of milk, fresh fish, Chinese cabbage, and fruits have preventive effects against urothelial cancer.

[The second-line chemotherapy for urological cancers]

This review summarizes second-line chemotherapy for testicular cancer and urothelial cancer. For testicular cancer, the combination of bleomycin (BLM), etoposide (ETP), and cisplatin (CDDP) (BEP) is commonly used as an induction therapy. The combination of vinblastine (VLB), ifosfamide (IFM) and CDDP (VeIP) or ETP, IFM, and CDDP (VIP) is used for the second-line chemotherapy. When the efficacy of VeIP and VIP is not sufficient, high-dose chemotherapy or chemotherapy with new anticancer agents has been used for the second-line chemotherapy. High-dose chemotherapy showed long-term survival rates of 30-50%, but patients with testicular cancer resistance to CDDP have poor outcomes. Although new anticancer agents, such as paclitaxel (TXL), gemcitabine (GEM) and irinotecan have been introduced, further examinations are needed to evaluate these drugs. The combination of methotrexate, VLB, adriamycin, and CDDP (MVAC) is used as the standard chemotherapy for urothelial cancer. The outcomes of MVAC are favorable, but the duration of response is short and long-term survival cannot be expected. Recently, the efficacy of new anticancer agents including TXL and GEM against urothelial cancers has been demonstrated. Although TXL and GEM combination therapy as the second-line chemotherapy has some effects, more evidence needs to be accumulated to establish it as a second-line treatment.

Radio-frequency ablation of renal cell carcinoma in patients who were at significant risk

OBJECTIVE

Although radio-frequency ablation (RFA) has been recently applied as a minimally invasive treatment option for renal cell carcinoma (RCC), indication of this modality remains a critical issue due to the lack of complete tumor destruction as well as the uncertainty of its long-term efficacy. We report the efficacy of RFA for nine carefully selected patients with RCC who had significant reason to avoid invasive surgical treatment under general anesthesia.

METHODS

Radio-frequency ablation was performed under epidural or local anesthesia by ultrasound or computed tomography (CT) guidance in nine patients with biopsy proven RCC (mean diameter, 38 mm; range, 20-53 mm), who were at significant operative or anesthetic risk for invasive surgery. Follow-up enhanced CT scans or magnetic resonance images were evaluated every 3-6 months and an evaluation of metastasis was performed every 6 months.

RESULTS

At a mean follow-up of 17 months, seven (78%) of the nine patients with renal tumor showed no tumor enhancement. The renal function of all patients was well preserved. All patients were able to continue undergoing their respective treatments for active diseases in other organs in parallel to the RFA treatment. No distant metastasis, urine leakage were reported and one case of temporary hematuria and one case of peri-renal hemorrhage not requiring blood transfusion were encountered. Intra-operative ultrasonography was useful in the real-time monitoring of the minimally excessive extension of ablation into the normal parenchyma.

CONCLUSION

Radio-frequency ablation appears to be an effective and safe minimally invasive therapeutic option for selected patients with RCC who have reason to avoid invasive surgery under general anesthesia.

Downregulation of Smac/DIABLO expression in renal cell carcinoma and its prognostic significance

PURPOSE

Second mitochondria-derived activator of caspase/direct inhibitor of apoptosis-binding protein with low pI (Smac/DIABLO) was recently identified as a protein that is released from mitochondria in response to apoptotic stimuli and promotes apoptosis by antagonizing inhibitor of apoptosis proteins. Furthermore, Smac/DIABLO plays an important regulatory role in the sensitization of cancer cells to both immune- and drug-induced apoptosis. However, little is known about the clinical significance of Smac/DIABLO in various cancers, including renal cell carcinoma (RCC). This study examined Smac/DIABLO expression in 78 healthy kidneys and 78 RCCs.

MATERIALS AND METHODS

The level of Smac/DIABLO expression was quantified by Western blot analysis using nonfixed fresh frozen tissues.

RESULTS

The expression of Smac/DIABLO was lower in RCC compared with the autologous normal kidney. Sixty-four (82%) of 78 of RCC expressed Smac/DIABLO, and 18% were negative, whereas 100% of normal kidney tissues were positive. In stage I/II RCC, 96% expressed Smac/DIABLO, whereas only 50% expressed Smac/DIABLO in stage III/IV. Smac/DIABLO expression inversely correlated with the grade of RCC. Patients with RCC expressing Smac/DIABLO had a longer postoperative disease-specific survival than those without Smac/DIABLO expression in the 5-year follow-up. Transfection with Smac/DIABLO cDNA enhanced tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) -mediated and cisplatin-mediated cytotoxicity in RCC.

CONCLUSION

The present study demonstrates for the first time that Smac/DIABLO expression was downregulated in RCC and that no Smac/DIABLO expression in RCC predicted a worse prognosis. In addition, transfection with Smac/DIABLO sensitized RCC to TRAIL/cisplatin-induced apoptosis. These results suggest that Smac/DIABLO expression in RCC may be used as a prognostic parameter, and that enhancement of Smac/DIABLO expression in RCC may potentiate immunotherapy and chemotherapy.