Diabetes Mellitus is Independently Associated with an Increased Risk of Mortality in Patients with Clear Cell Renal Cell Carcinoma

Hsa_circ_0086414/transducer of ERBB2 (TOB2) axis-driven lipid elimination and tumor suppression in clear cell renal cell cancer via perilipin 3

BACKGROUND

Renal cell cancer (RCC) is characterized by abnormal lipid accumulation. However, the specific mechanism by which such lipid deposition is eliminated remains unclear. Circular RNAs (circRNAs) widely regulate various biological processes, but the effect of circRNAs on lipid metabolism in cancers, especially clear cell renal cell carcinoma (ccRCC), remains poorly understood.

METHODS

The downregulated circRNA, hsa_circ_0086414, was identified from high-throughput RNA-sequencing data of human ccRCC and pair-matched normal tissues. The target relationship between circRNA_0086414 and miR-661, and the transducer of ERBB2 (TOB2) was predicted using publicly available software programs and verified by luciferase reporter assays. The clinical prognostic value of TOB2 was evaluated by bioinformatic analysis. The expression levels of circRNA_0086414, miR-661, TOB2, and perilipin 3 (PLIN3) were measured by quantitative reverse-transcription polymerase chain reaction or western blot analysis. Cell Counting Kit-8, transwell assays, and xenograft models were employed to assess the biological behaviors of the hsa_circ_0086414/TOB2 axis. Oil Red staining and triglyceride assay was conducted to assess lipid deposition.

RESULTS

Herein, we identified a downregulated circRNA, hsa_circ_0086414. Functionally, the restored hsa_circ_0086414 inhibited ccRCC proliferation, metastasis, and lipid accumulation in vitro and in vivo. Furthermore, the downregulated TOB2 predicted adverse prognosis and promoted cancer progression and lipid deposition in ccRCC. Mechanically, the binding of hsa_circ_0086414 to miR-661, as a miRNA sponge, upregulates the expression of TOB2, wielding an anti-oncogene effect. Importantly, the restored hsa_circ_0086414/TOB2 axis significantly contributed to the elimination of lipid deposition by inhibiting the lipid metabolism regulator PLIN3 in ccRCC cells.

CONCLUSIONS

Our data highlight the importance of the hsa_circ_0086414/TOB2/PLIN3 axis as a tumor suppressor and lipid eliminator in ccRCC. The positive modulation of the hsa_circ_0086414/TOB2 axis might lead to the development of novel treatment strategies for ccRCC.

Effect of smoking, hypertension and lifestyle factors on kidney cancer - perspectives for prevention and screening programmes

Renal cell carcinoma (RCC) incidence has doubled over the past few decades. However, death rates have remained stable as the number of incidental renal mass diagnoses peaked. RCC has been recognized as a European health care issue, but to date, no screening programmes have been introduced. Well-known modifiable risk factors for RCC are smoking, obesity and hypertension. A direct association between cigarette consumption and increased RCC incidence and RCC-related death has been reported, but the underlying mechanistic pathways for this association are still unclear. Obesity is associated with an increased risk of RCC, but interestingly, improved survival outcomes have been reported in obese patients, a phenomenon known as the obesity paradox. Data on the association between other modifiable risk factors such as diet, dyslipidaemia and physical activity with RCC incidence are conflicting, and potential mechanisms underlying these associations remain to be elucidated.

Restoring the epigenetically silenced lncRNA COL18A1-AS1 represses ccRCC progression by lipid browning via miR-1286/KLF12 axis

Abnormal accumulation of lipids has been highlighted in the progression of clear cell renal cell carcinoma (ccRCC). However, the underlying mechanism remains unclear. Emerging evidence suggests long noncoding RNAs (lncRNAs) participate in the regulation of lipid metabolism. In this study, we found lncRNA COL18A1-AS1 was downregulated in ccRCC and that higher COL18A1-AS1 expression indicated better prognosis. Decreased COL18A1-AS1 expression was caused by DNA methylation at the CpG islands within its promoter. Restoring the epigenetically silenced COL18A1-AS1 repressed tumor progression, promoted lipid browning and consumption in vitro and in vivo. Mechanistically, COL18A1-AS1 could competitively bind miR-1286 to increase the expression of Krüppel-like factor 12 (KLF12). Downregulation of COL18A1-AS1 in ccRCC resulted in the low expression of KLF12. COL18A1-AS1/KLF12 positively regulated uncoupling protein 1 (UCP1)-mediated lipid browning, which promotes tumor cell "slimming" and inhibits tumor progression. When tumor cell "slimming" occurred, lipid droplets turned into tiny pieces, and lipids were consumed without producing ATP energy. Taken together, our findings on COL18A1-AS1-miR-1286/KLF12 axis revealed a potential mechanism of abnormal accumulation of lipids in ccRCC and could be a promising therapeutic target for ccRCC patients.

The Role of Metabolic Factors in Renal Cancers

An increasing number of evidence indicates that metabolic factors may play an important role in the development and progression of certain types of cancers, including renal cell carcinoma (RCC). This tumour is the most common kidney cancer which accounts for approximately 3–5% of malignant tumours in adults. Numerous studies indicated that concomitant diseases, including diabetes mellitus (DM) and hypertension, as well as obesity, insulin resistance, and lipid disorders, may also influence the prognosis and cancer-specific overall survival. However, the results of studies concerning the impact of metabolic factors on RCC are controversial. It appears that obesity increases the risk of RCC development; however, it may be a favourable factor in terms of prognosis. Obesity is closely related to insulin resistance and the development of diabetes mellitus type 2 (DM2T) since the adipocytes in visceral tissue secrete substances responsible for insulin resistance, e.g., free fatty acids. Interactions between insulin and insulin-like growth factor (IGF) system appear to be of key importance in the development and progression of RCC; however, the exact role of insulin and IGFs in RCC pathophysiology remains elusive. Studies indicated that diabetes increased the risk of RCC, but it might not alter cancer-related survival. The risk associated with a lipid profile is most mysterious, as numerous studies provided conflicting results. Even though large studies unravelling pathomechanisms involved in cancer growth are required to finally establish the impact of metabolic factors on the development, progression, and prognosis of renal cancers, it seems that the monitoring of health conditions, such as diabetes, low body mass index (BMI), and lipid disorders is of high importance in clear-cell RCC.

The platelet-to-lymphocyte ratio as a significant prognostic factor to predict survival outcomes in patients with synchronous metastatic renal cell carcinoma

Purpose

The clinical impact of the platelet-to-lymphocyte ratio (PLR) on the prognosis of patients with metastatic renal cell carcinoma (mRCC) remains controversial. We investigated the associations between elevation of the PLR and disease prognosis in patients with synchronous mRCC.

Materials and Methods

The data of 1,505 patients with synchronous mRCC were retrospectively analyzed. The entire cohort was stratified into two subgroups according to PLR. Kaplan–Meier and Cox proportional analyses were performed to investigate the possible associations between the PLR and disease prognosis.

Results

There were 921 patients with a high PLR and 584 patients with a low PLR by use of the cutoff of 146. The patients with a high PLR had worse clinical characteristics in terms of advanced clinical stage (p<0.001) and rate of lymph node invasion (p=0.036). The Kaplan–Meier analysis showed that patients with a high PLR had significantly shorter overall survival (OS) (p<0.001) and cancer-specific survival (CSS) (p<0.001). The multivariate Cox analysis revealed that the PLR was an independent predictor for shorter OS (hazard ratio [HR], 1.345; 95% confidence interval [CI], 1.183–1.530; p<0.001) and CSS (HR, 1.318; 95% CI, 1.156–1.502; p<0.001). In the subgroup analyses, the PLR showed a significant association with survival outcomes in the subgroup with clear cell type (all p<0.05) but not in the subgroup with the non–clear cell type.

Conclusions

The PLR was an independent prognostic factor for survival outcomes in patients with mRCC. However, the association was statistically significant only in patients with clear cell type mRCC.

The number of metabolic features as a significant prognostic factor in patients with metastatic renal cell carcinoma

The effect of metabolic characteristics on the prognosis of patients with metastatic renal cell carcinoma remains controversial. We investigated the associations between metabolic features of each individual and disease prognosis in patients with metastatic renal cell carcinoma. Data of 1,584 patients with metastatic renal cell carcinoma from a multi-institutional database were retrospectively analyzed. The entire cohort was stratified into three subgroups according to how many patients had abnormal metabolic features (hypertension, diabetes mellitus, and low body mass index). The Kaplan-Meier and Cox proportional analyses were performed to investigate the associations between abnormal metabolic features and disease prognosis. mThere were 465 subjects without any metabolic features, 995 with one or two, and 124 with three. When the survival outcomes were compared according to the number of metabolic features, patients with higher numbers of metabolic features had significantly shorter overall and cancer-specific survival than those with fewer metabolic features (all p values <0.05). The multivariate Cox analysis showed that the number of metabolic features was an independent predictor for shorter cancer-specific and overall survival (all p values < 0.05). When performing subgroup analysis according to the cellular type, significant results were only obtained among the clear cell subtype subgroup, with the association not being significant in the non-clear cell subtype cohort. Patients with more metabolic features had significantly worse survival outcomes than those with fewer metabolic features. However, the association was only statistically significant in patients with clear cell-type metastatic renal cell carcinoma.

The oxidation and hypoglycaemic effect of sorafenib in streptozotocin-induced diabetic rats

Background

Diabetes reduces the activity of CYP3A4 and may increase the exposure for the drugs metabolized by the isoenzyme. Sorafenib is a multi-targeted tyrosine kinase inhibitor (TKI), used for the treatment of advanced renal cell carcinoma, hepatocellular carcinoma and radioactive iodine resistant thyroid carcinoma. The TKI undergoes CYP3A4-dependent oxidative transformation, which may be influenced by hyperglycaemia. The aim of the study was to compare the oxidation for sorafenib between healthy and streptozotocin-induced diabetic rats. Additionally, the effect of sorafenib on glucose levels was investigated.

Methods

The rats were assigned to the groups: streptozotocin-induced diabetic (DG, n = 8) or healthy (HG, n = 8). The rats received sorafenib orally as a single dose of 100 mg/kg. The plasma concentrations of sorafenib and its metabolite N-oxide were measured with the validated high-performance liquid chromatography with ultraviolet detection.

Results

The difference between groups in C_max and AUC_0−t values for sorafenib were significant (p = 0.0004, p = 0.0104), and similarly for the metabolite (p = 0.0008, p = 0.0011). Greater exposure for the parent drug and analysed metabolite was achieved in diabetic group. However, the C_max, AUC_0−t, and AUC_0−∞ ratios between the metabolite and sorafenib were similar in both groups. The significant reduction of glycaemia was observed only in the diabetic animals.

Conclusion

The findings of the study provide evidence that diabetes significantly influence on the exposition for sorafenib and its metabolite, but similar ratios N-oxide/sorafenib for AUC and C_max in healthy and diabetic animals suggest that oxidation of the TKI is rather unchanged. Additionally, sorafenib-associated hypoglycaemia was confirmed in diabetic animals.

MiR-765 functions as a tumour suppressor and eliminates lipids in clear cell renal cell carcinoma by downregulating PLP2

Background

Lipid accumulation has been highlighted in cancer development and progression, but the exact mechanism remains unclear in renal cell carcinoma (RCC). MicroRNAs (miRNAs) have been confirmed to participate in the pathological processes of cancers, including tumour occurrence and inhibition. However, the role and mechanism of miR-765 have not been elucidated in clear cell renal cell carcinoma (ccRCC).

Methods

Using The Cancer Genome Atlas (TCGA) database and qRT-PCR, we investigated differences in miR-765 and proteolipid protein 2 (PLP2) expression, as well as their clinical relevance. To investigate the function of miR-765 and PLP2 in ccRCC, we performed in vitro and in vivo experiments to explore their biological functions in ccRCC.

Findings

In this study, we showed that miR-765 was upregulated in the plasma of ccRCC patients after tumour resection. Consistently, ccRCC tissues had low expression of miR-765 when compared with corresponding non-cancerous tissues. Overexpression of miR-765 suppressed cell proliferation and metastasis in vitro and in vivo. Mechanistic studies demonstrated that PLP2 was a direct target gene of miR-765. PLP2 was highly expressed in ccRCC tissues, and high PLP2 levels were positively correlated with higher tumour stage and grade and poor prognosis. PLP2 expression was negatively correlated with the miR-765 level in patient samples. We further showed that PLP2 restrained the cell metastasis and proliferation induced by miR-765 and reduced the lipid-eliminating effects of miR-765 in renal cancer cells.

Interpretation

Our findings suggest that miR-765 may function as a tumour suppressor and eliminate lipids in clear cell renal cell carcinoma by targeting PLP2.

Funding

This work was funded the grants from the National Natural Scientific Foundation of China (Grant No. 81672528, 81672524, 81602218, 31741032, 81902588).

Validation of risk factors for recurrence of renal cell carcinoma: Results from a large single-institution series

Purpose

To validate prognostic factors and determine the impact of obesity, hypertension, smoking and diabetes mellitus (DM) on risk of recurrence after surgery in patients with localized renal cell carcinoma (RCC).

Materials and methods

We performed a retrospective cohort study among patients that underwent partial or radical nephrectomy at Weill Cornell Medicine for RCC and collected preoperative information on RCC risk factors, as well as pathological data. Cases were reviewed for radiographic evidence of RCC recurrence. A Cox proportional-hazards model was developed to determine the contribution of RCC risk factors to recurrence risk. Disease-free survival and overall survival were analyzed using the Kaplan-Meier method and log-rank test.

Results

We identified 873 patients who underwent surgery for RCC between the years 2000–2015. In total 115 patients (13.2%) experienced a disease recurrence after a median follow up of 4.9 years. In multivariate analysis, increasing pathological T-stage (HR 1.429, 95% CI 1.265–1.614) and Nuclear grade (HR 2.376, 95% CI 1.734–3.255) were independently associated with RCC recurrence. In patients with T1-2 tumors, DM was identified as an additional independent risk factor for RCC recurrence (HR 2.744, 95% CI 1.343–5.605). Patients with DM had a significantly shorter median disease-free survival (1.5 years versus 2.6 years, p = 0.004), as well as median overall survival (4.1 years, versus 5.8 years, p<0.001).

Conclusions

We validated high pathological T-stage and nuclear grade as independent risk factors for RCC recurrence following nephrectomy. DM is associated with an increased risk of recurrence among patients with early stage disease.

Melatonin/PGC1A/UCP1 promotes tumor slimming and represses tumor progression by initiating autophagy and lipid browning

Metabolic adaptations are emerging hallmarks of cancer progression and cellular transformation. Clear cell renal cell carcinoma (ccRCC) is a metabolic disease defined histologically by lipid accumulation and lipid storage, which promote tumor cell survival; however, the significance of eliminating the lipid remains unclear. Here, we demonstrate that melatonin activates transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator 1A (PGC1A) and uncoupling protein 1 (UCP1)-dependent lipid autophagy and a lipid browning program to elicit a catabolic state called "tumor slimming," thus suppressing tumor progression. Metabolic coregulator data analysis revealed that PGC1A expression was decreased in ccRCC tissues versus normal tissues, and poor patient outcome was associated with lower expression of PGC1A in The Cancer Genome Atlas (TCGA-KIRC). PGC1A was downregulated in ccRCC and associated with disease progression. Restoration of PGC1A expression by melatonin in ccRCC cells significantly repressed tumor progression and eliminated the abnormal lipid deposits. Furthermore, a phenomenon called "tumor slimming" was observed, in which tumor cell volume was reduced and lipid droplets transformed into tiny pieces. Additional studies indicated that melatonin promoted "tumor slimming" and suppressed ccRCC progression through PGC1A/UCP1-mediated autophagy and lipid browning. During this process, autophagy and lipid browning eliminate lipid deposits without providing energy. These studies demonstrate that the novel "tumor slimming" pathway mediated by melatonin/PGC1A/UCP1 exhibits prognostic potential in ccRCC, thus revealing the significance of monitoring and manipulating this pathway for cancer therapy.

Evaluation of the prognostic role of co-morbidities on disease outcome in renal cell carcinoma patients

BACKGROUND

Co-morbidities may induce local and systemic tumor progression of renal cell carcinoma (RCC); however, the prognostic impact of co-morbidities has not yet been well characterized.

PATIENTS AND METHODS

RCC patients (n = 2206) surgically treated at three academic institutions in the US and Europe were included in the analysis. Presence of diabetes mellitus, hypertension, chronic kidney disease, chronic obstructive pulmonary disease, coronary heart disease, and hypothyroidism were investigated for their association with clinicopathological features and cancer-specific survival.

RESULTS

Hypertension was associated with less advanced T stages (p = 0.025), a lower risk of lymph-node (p = 0.026) and distant metastases (p = 0.001), and improved cancer specific survival in univariable analysis (HR 0.81 95% CI 0.69-0.96, p = 0.013). However, hypertension was not an independent prognostic factor after adjustment for TNM stages, grading, and ECOG performance status (HR 0.95, 95% CI 0.80-1.12; p = 0.530). A correlation between the use of concomitant anti-hypertensive medications and improved survival outcome was not identified. All other investigated co-morbidities did not show significant associations with clinicopathological features or cancer-specific survival.

CONCLUSION

Although the investigated co-morbidities are capable or inducing pathophysiological changes that are predisposing factors for tumor progression, none is an independent prognostic factor in patients with RCC.

Type 2 Diabetes in Relation to the Risk of Renal Cell Carcinoma Among Men and Women in Two Large Prospective Cohort Studies

OBJECTIVE

We assessed whether type 2 diabetes is associated with renal cell carcinoma (RCC), independent of key potential confounders, in two large prospective cohorts with biennially updated covariate data.

RESEARCH DESIGN AND METHODS

A total of 117,570 women from the Nurses' Health Study (NHS) and 48,866 men from the Health Professionals Follow-Up Study (HPFS) were followed from 1976 and 1986, respectively, through 2014. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% CIs for associations between type 2 diabetes and pathology-confirmed RCC, overall and by stage, grade, and histologic subtype.

RESULTS

During 38 years of follow-up in the NHS, we confirmed 418 RCC case subjects, including 120 fatal cases. Over 28 years in the HPFS, we confirmed 302 RCC case subjects, including 87 fatal cases. Women with type 2 diabetes had a significantly increased risk of RCC compared with women without type 2 diabetes (multivariable HR 1.53; 95% CI 1.14-2.04), with some evidence that the association was stronger for ≤5 (HR 2.15; 95% CI 1.44-3.23) than >5 (HR 1.22; 95% CI 0.84-1.78) years' duration of type 2 diabetes (P_difference 0.03). Among men, type 2 diabetes was not associated with total RCC (HR 0.89; 95% CI 0.56-1.41) or with RCC defined by stage, grade, or subtype. Sample sizes for analyses by stage, grade, and subtype were limited.

CONCLUSIONS

We found that type 2 diabetes was independently associated with a greater risk of RCC in women but not in men.

Diabetes and kidney cancer outcomes: a propensity score analysis

There is conflicting evidence whether diabetes is associated with survival outcomes in patients undergoing a nephrectomy for renal cell carcinoma. We performed a retrospective review of 1034 patients undergoing nephrectomy for unilateral, M0, renal cell carcinoma between 2000 and 2016 at a tertiary academic center. Inverse probability of treatment weights were derived from a propensity score model based on various clinical, surgical, and pathological characteristics. We used Cox proportional hazard models to evaluate the association between diabetes and disease-free survival, cancer-specific survival, and overall survival in the sample weighted by the inverse probability of treatment weights. Furthermore, to evaluate whether severity of diabetes was associated with survival outcomes, we performed separate analyses where inverse probability of treatment weights were computed based on the probability of having diabetes that was controlled by medication. Of the 1034 patients, 180 (17 %) had diabetes. Of these, 139 (77 %) patients required medications for diabetes control while the remaining 41 (23 %) had diet controlled diabetes. Median follow-up was 50 months (IQR 17-86). Diabetes at the time of surgery was not significantly associated with disease-free survival (HR 1.11, 95 % CI 0.64 -1.91), cancer-specific survival (HR 0.96, 95 % CI 0.49-1.91), or overall survival (HR 1.28, 95 % CI 0.84-1.95). We found similar results when we compared diabetics controlled with medication vs. non-diabetics or diet controlled diabetics. In summary, we found no significant association between diabetes and survival outcomes in patients undergoing nephrectomy for M0 renal cell carcinoma. These results suggest that diabetics should be treated and followed in a similar manner to non-diabetics.

The joint effects of arsenic and risk diplotypes of insulin-like growth factor binding protein-3 in renal cell carcinoma

The association between renal cell carcinoma (RCC) and diabetes mellitus (DM), alcohol consumption, insulin-like growth factor binding protein-3 (IGFBP-3) gene, and arsenic exposure, has been the subject of independent studies. However, few studies have examined the combined effect of these factors on RCC risk. The aim of this study was to examine the association between these risk factors and the odds ratio (OR) of RCC. A hospital-based case-control study was conducted in 398 RCC patients and 756 age- and gender-matched non-cancer controls. Genomic DNA was used to examine the genotype of IRS-1 (Gly972Arg), PI3-K (Met362Ile), IGFBP-3 (A[-202]C), and IGFBP-3 (C[-1590]A) by PCR-RFLP. Profiles of urinary arsenic were measured by high performance liquid chromatography linked with hydride generator and atomic absorption spectrometry. Participants who had never consumed alcohol and who had high total levels of urinary arsenic and DM had a high OR of RCC. IGFBP-3 (A[-202]C) and IGFBP-3 (C[-1590]A) were in linkage disequilibrium. Participants carrying high-risk IGFBP-3 diplotypes A-C/C-C, A-A/A-C, and C-A/C-A had a significantly higher odds ratio (OR) and 95% confidence interval (2.80, 1.91-4.12) of RCC compared to those carrying other IGFBP-3 diplotypes. This is the first study to show that borderline significant interaction of high total levels of urinary arsenic and IGFBP-3 high-risk diplotypes significantly enhanced the OR of RCC. Our data also provide evidence that subjects with more risk factors (e.g., high total levels of urinary arsenic, never consumed alcohol, IGFBP-3 high-risk diplotypes) may experience a higher OR of RCC.

Simultaneous metastases of clear cell renal cell carcinoma to the urinary bladder and left retroperitoneal space: A case report and review of the literature

The present study describes an extremely rare case of simultaneous metastases of clear cell renal cell carcinoma (ccRCC) to the urinary bladder and left retroperitoneal space, occurring subsequent to an open radical nephrectomy. A review of the literature is also considered. A 70-year-old man presenting with diabetes mellitus and hypertension was referred to West China Hospital (Chengdu, China) with constant left flank pain that had been apparent for 2 months. Ultrasonography identified a heterogeneous tumor with a solid component measuring 4.4×3.4×5.0 cm, and computed tomography (CT) revealed a circumscribed and contrast-enhanced tumor in the left kidney. Subsequent pathological analysis of the specimen, obtained from an open radical nephrectomy, confirmed the presence of ccRCC. At 1 month after the radical nephrectomy, an abdominopelvic CT scan identified tumors located on the posterior bladder wall and also in the left retroperitoneal space, forming due to hematuria and acute urinary clot retention. There was no evidence of metastasis to the lungs, bones or other organs. A transurethral resection of the bladder tumor was performed and pathological analysis of the bladder specimen demonstrated metastatic ccRCC. Extensive hydrothorax and general anasarca presented half a month after the transurethral resection, with the patient subsequently succumbing 15 days later.

Determinants of mortality in patients with type 2 diabetes: a review

We aimed to review and summarize the evidence from accomplished trials analyzing factors influencing mortality in patients with T2DM and to provide some recommendations for targets and treatment in the European region. The following databases were searched for relevant trials: PubMed and the Cochrane Library. Of 3.806 citations, 134 trials met our inclusion criteria.

RESULTS

The reduction in lifetime for 65 + -years-old patients having less than 10 years T2DM amounts to 1.8 years. Having T2DM for more than 10 years lifetime will be reduced by 2.7 years. However, the lifetime shortening factor of T2DM will even be stronger for 40 + -years-old patients at onset. Males will lose 11.6 years of life and 18.6 QUALYs. T2DM among females will reduce life by 14 QUALYs by 22 years. From a statistical point of view, the highest mortality rate will occur in an over 55-years-old European smoking and non-compliant diabetic woman with alcohol abuse living in a rural area with a low level of education and a low socio-economic status. Furthermore, other co-morbidities such as cardiovascular diseases, gout, and depression affect mortality. Additionally, mortality will increase with a BMI over 35 and also with a BMI under 20-25. This refers to the obesity paradox indicating a higher mortality rate among normal weight patients with T2DM compared to overweight patients with T2DM. HbA1c-levels between 6.5 % and 7 % are associated with the lowest impact on mortality.

Patients with ClearCode34-identified molecular subtypes of clear cell renal cell carcinoma represent unique populations with distinct comorbidities

PURPOSE

The 34-gene classifier, ClearCode34, identifies prognostically distinct molecular subtypes of clear cell renal cell carcinoma (ccRCC) termed clear cell A (ccA) and clear cell B (ccB). The primary objective of this study was to describe clinical characteristics and comorbidities of relevance in patients stratified by ClearCode34.

PATIENTS AND METHODS

In this retrospective analysis, 282 patients from Moffitt Cancer Center with ccRCC with gene expression analyses of the primary tumor were identified and ClearCode34 was applied to identify tumors as ccA or ccB. The medical record and institutional databases were queried to define patient characteristics, comorbidities, and outcomes.

RESULTS

We validated in this external cohort the superior overall survival, cancer-specific survival, and recurrence-free survival of ccA patients relative to ccB patients (P<0.001). Addressing other clinical characteristics, the ccA patients were more likely to be obese (48% vs. 34%, P = 0.021) and diabetic (26% vs. 13%, P = 0.035). The ccA patients also trended toward having been more frequent users of angiotensin system inhibitors (71% vs. 52%, P = 0.055). In multivariate analyses, ccB status is independently associated with inferior cancer-specific survival (hazard ratio = 3.26, 95% confidence interval: 1.84-5.79) and overall survival (hazard ratio = 2.50, 95% confidence interval: 1.53-4.08).

CONCLUSIONS

ClearCode34, after considering distinct patterns of comorbidities in each molecular subtype, remains a strong prognostic tool in patients with ccRCC. Obesity and diabetes mellitus emerged as factors that may influence ccRCC phenotypes and further studies investigating the effect of these metabolic conditions functionally onto tumor biology are warranted. Additionally, use of angiotensin system inhibitors could be studied in the context of ccRCC molecular classification in future studies to better understand its effect on ccRCC outcomes.

Risk of metastasis for T1a renal cell carcinoma

INTRODUCTION

While active surveillance for small renal mass is gaining acceptance, controversy still continues on true metastatic potential of small renal cell carcinoma (RCC). Thus, we investigated the risks of synchronous/metachronous metastases and their potential predictors among T1a RCC patients who underwent surgical treatment.

METHODS

We reviewed data from 2114 patients who received radical or partial nephrectomy for small renal tumor (≤ 4 cm) from 1990 to 2013. For our study, patients were stratified into four different groups according to tumor size (group 1: 0-1.0 cm, group 2: 1.1-2.0 cm, group 3: 2.1-3.0 cm, group 4: 3.1-4.0 cm). Univariate and multivariate analyses were performed to analyze metastatic potentials according to tumor size and identify useful predictors of metastases.

RESULTS

Among 1913 T1a RCC patients, there were low but nonnegligible rates of metastases (group 2: 1.1 %, group 3: 3.3 %, group 4: 6.0 %, respectively). Kaplan-Meier analysis showed significant differences in metastasis-free survivals between groups (p < 0.001). A linear positive association was observed between tumor size and metastatic rate (p < 0.001). Diabetic T1a RCC patients showed significantly inferior metastasis-free survival than nondiabetic counterparts (p = 0.003). Multivariate analysis revealed that tumor size and history of diabetes mellitus were independently associated with metastasis in T1a RCC.

CONCLUSIONS

As T1a RCCs present low but nonnegligible risk of metastasis, patients with small renal mass should be counseled on such risk when offered active surveillance. Larger tumor size and history of diabetes mellitus may be associated with higher risk of metastasis in T1a RCC.

The Impact of Diabetes Mellitus on Renal Cell Carcinoma Prognosis: A Meta-Analysis of Cohort Studies

Previous studies that investigated the relationship between DM and survival in renal cell carcinoma (RCC) patients reported inconsistent findings. Hence, we conducted a meta-analysis to obtain a more precise evaluation of the prognostic significance of DM in RCC. A systematic review was conducted with PubMed, Embase, and Web of Science to identify relevant articles that evaluated the effect of DM on RCC patients. Based on the inclusion and quality assessment criteria, 18 studies were eligible for the meta-analysis. Pooled hazard ratios (HR) and corresponding 95% confidence intervals (CI) for overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS) were calculated by standard meta-analysis techniques. The results suggested that DM was associated with poor OS (HR 1.56, 95% CI, 1.35-1.81, P < 0.001), poor CSS (HR 2.03, 95% CI, 1.37-3.01, P < 0.001), and poor RFS (HR 1.73, 95% CI, 1.25-2.39, P = 0.012). In addition, for patients with localized RCC, patients with clear cell RCC, or patients receiving nephrectomy, DM was associated with both poor OS and CSS by subgroup analyses. Our study revealed that there was a significant negative impact of DM on OS, CSS, and RFS in RCC patients. Therefore, more attention should be paid to RCC patients with preexisting DM because of their poor prognosis.

Diabetes Mellitus as an Independent Predictor of Survival of Patients Surgically Treated for Renal Cell Carcinoma: A Propensity Score Matching Study

PURPOSE

Controversy continues about the prognostic significance of diabetes mellitus in patients with renal cell carcinoma. We investigated the relationship between diabetes mellitus and prognosis in patients with renal cell carcinoma who underwent surgical treatment.

MATERIALS AND METHODS

We reviewed data on 3,075 consecutive patients treated with radical or partial nephrectomy for nonmetastatic renal cell carcinoma from 1988 to 2013. The propensity score of a diabetes mellitus history was calculated and 417 patients with diabetes were matched to 814 without diabetes in a 1:2 ratio. The potential association of preexisting diabetes and preoperative HbA1c with outcomes was tested. Univariate and multivariate analyses were performed to identify independent predictors of progression-free, cancer specific and overall survival.

RESULTS

Before matching, patients with diabetes showed worse prognosis in terms of progression-free, overall and cancer specific survival (each p<0.001). In matched cohorts 1,231 patients with diabetes showed progression-free (p=0.001), cancer specific (p<0.001) and overall survival (p<0.001) inferior to that in patients without diabetes. On multivariate analyses diabetes was an independent predictor of disease progression (HR 1.766 p=0.002), all cause mortality (OR 1.825, p=0.001) and cancer specific mortality (HR 2.266, p=0.001). Among patients with diabetes who had available preoperative HbA1c data high HbA1c independently predicted postoperative disease progression (HR 2.221, p=0.023).

CONCLUSIONS

Diabetes mellitus is an independent predictor of cancer specific and overall survival in patients who undergo surgery for renal cell carcinoma. Also, in patients with diabetes mellitus poor glycemic control is associated with a higher risk of progression.

Pre-existing type 2 diabetes mellitus is an independent risk factor for mortality and progression in patients with renal cell carcinoma

Malignancies are one of the main causes of mortality in diabetic patients; however, to date, very limited data have been reported on the specific influence of type 2 diabetes mellitus (T2DM) on the survival of patients with renal cell carcinoma (RCC). In the present long-term retrospective study, we investigated whether T2DM may influence the overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS) in patients with surgically treated RCC. Medical records of 924 patients treated by radical or partial nephrectomy for sporadic, unilateral RCC were reviewed. Patients with type-1 DM and with T2 DM receiving insulin treatment were excluded. Survival estimates were calculated according to the Kaplan-Meier method and compared with the log-rank test. Univariate and multivariate analyses were performed using the Cox regression model.Of the 924 RCC patients, 152 (16.5%) had T2DM. Mean follow-up was 68.5 months. Mean OS was 41.3 and 96.3 months in T2DM and non-T2DM patients, respectively (P < 0.0001).The estimated CSS rates at 1, 3, and 5 years in T2DM versus non-T2DM patients were 63.4% versus 76.7%, 30.4% versus 56.6%, and 16.3% versus 48.6%, respectively (P = 0.001). Mean PFS was significantly lower (31.5 vs 96.3 months; P < 0.0001) in the T2DM group. At multivariate analysis, T2DM was an independent adverse prognostic factor for OS (hazard ratio [HR]  = 3.44; 95% confidence interval [CI]:2.40-4.92), CSS (HR = 6.39; 95% CI: 3.78-10.79), and PFS (HR = 4.71; 95% CI: 3.11-7.15). In conclusion, our findings suggest that patients with RCC and pre-existing T2DM have a shorter OS, increased risk of recurrence, and higher risk for kidney cancer mortality than those without diabetes.

The association between metformin use and oncologic outcomes among surgically treated diabetic patients with localized renal cell carcinoma

INTRODUCTION

Metformin inhibits renal cell carcinoma (RCC) cell proliferation both in vitro and in vivo; however, clinical data regarding the effect of metformin in patients with RCC are lacking. We evaluated the association of metformin use with outcomes among patients with surgically treated localized RCC.

MATERIALS AND METHODS

We identified 283 consecutive diabetic patients treated surgically for localized RCC between January 1, 1994 and December 31, 2008. Clinicopathologic features were compared between patients exposed to metformin (n = 83, 29%) and those who were not (n = 200, 71%). Progression-free, cancer-specific, and overall survival rates were estimated with the Kaplan-Meier analysis, and Cox models were used to evaluate the association of metformin use with outcomes.

RESULTS AND CONCLUSIONS

Patients receiving metformin had a better renal function (median estimated glomerular filtration rate = 65 vs. 55 ml/min/1.73 m(2), P<0.001), performance status (Eastern Cooperative Oncology Group<1: 89% vs. 71%, P = 0.001), and lower Charlson comorbidity index (median = 2 vs. 3, P = 0.02) compared with those who did not, but were otherwise similar across other clinicopathologic features (P>0.05 for all). At a median postoperative follow-up of 8.1 years, patients exposed to metformin had similar 5-year progression-free (80% vs. 75%, P = 0.6) and cancer-specific survival rates (91% vs. 81%, P = 0.16), but significantly improved overall survival rate (79% vs. 62%, P = 0.01). However, metformin was not independently associated with the risks of progression, RCC-specific mortality, or all-cause mortality on multivariable analyses. In this surgical cohort of diabetic patients with M0 RCC, preoperative metformin exposure was associated with improved overall survival on unadjusted analysis. Although metformin was not independently associated with oncologic or survival outcomes, future studies appear warranted.