Natural History and Genomic Landscape of Chemotherapy-Resistant Muscle-Invasive Bladder Cancer.

PURPOSE: Patients with residual invasive bladder cancer after neoadjuvant chemotherapy (NAC) and radical cystectomy have a poor prognosis. Data on adjuvant therapy for these patients are conflicting. We sought to evaluate the natural history and genomic landscape of chemotherapy-resistant bladder cancer to inform patient management and clinical trials. METHODS: Data were collected on patients with clinically localized muscle-invasive urothelial bladder cancer treated with NAC and cystectomy at our institution between May 15, 2001, and August 15, 2019, and completed four cycles of gemcitabine and cisplatin NAC, excluding those treated with adjuvant therapies. Survival was estimated using the Kaplan-Meier method, and multivariable Cox proportional hazards models were used to identify predictors of recurrence-free survival (RFS). Genomic alterations were identified in targeted exome sequencing (Memorial Sloan Kettering Integrated Mutation Profiling of Actionable Cancer Targets) data from post-NAC specimens from a subset of patients. RESULTS: Lymphovascular invasion (LVI) was the strongest predictor of RFS (hazard ratio, 2.15 [95% CI, 1.37 to 3.39]) on multivariable analysis. Patients with ypT2N0 disease without LVI had a significantly prolonged RFS compared with those with LVI (70% RFS at 5 years). Lymph node yield did not affect RFS. Among patients with sequencing data (n = 101), chemotherapy-resistant tumors had fewer alterations in DNA damage response genes compared with tumors from a publicly available chemotherapy-naïve cohort (15% v 29%; P = .021). Alterations in CDKN2A/B were associated with shorter RFS. PIK3CA alterations were associated with LVI. Potentially actionable alterations were identified in more than 75% of tumors. CONCLUSION: Although chemotherapy-resistant bladder cancer generally portends a poor prognosis, patients with organ-confined disease without LVI may be candidates for close observation without adjuvant therapy. The genomic landscape of chemotherapy-resistant tumors is similar to chemotherapy-naïve tumors. Therapeutic opportunities exist for targeted therapies as adjuvant treatment in chemotherapy-resistant disease.

BET inhibitors as a therapeutic intervention in gastrointestinal gene signature-positive castration-resistant prostate cancer.

A subgroup of castration-resistant prostate cancer (CRPC) aberrantly expresses a gastrointestinal (GI) transcriptome governed by two GI-lineage-restricted transcription factors, HNF1A and HNF4G. In this study, we found that expression of GI transcriptome in CRPC correlates with adverse clinical outcomes to androgen receptor signaling inhibitor treatment and shorter overall survival. Bromo- and extra-terminal domain inhibitors (BETi) downregulated HNF1A, HNF4G, and the GI transcriptome in multiple CRPC models, including cell lines, patient-derived organoids, and patient-derived xenografts, while AR and the androgen-dependent transcriptome were largely spared. Accordingly, BETi selectively inhibited growth of GI transcriptome-positive preclinical models of prostate cancer. Mechanistically, BETi inhibited BRD4 binding at enhancers globally, including both AR and HNF4G bound enhancers while gene expression was selectively perturbed. Restoration of HNF4G expression in the presence of BETi rescued target gene expression without rescuing BRD4 binding. This suggests that inhibition of master transcription factors expression underlies the selective transcriptional effects of BETi. SIGNIFICANCE: GI transcriptome expression in CRPC is regulated by the HNF1A-HNF4G-BRD4 axis and correlates with worse clinical outcomes. Accordingly, BET inhibitors significantly reduce tumor cell growth in multiple GI-transcriptome-positive preclinical models of CRPC. Our studies point that expression of GI transcriptome could serve as a predictive biomarker to BETi therapy response.

Obesity shapes selection for driver mutations in cancer.

Obesity is a leading risk factor for cancer, but whether obesity is linked to specific genomic subtypes of cancer is unknown. Here, we examined the relationship between obesity and tumor genotype in two large clinicogenomic corpora. Obesity was associated with specific driver mutations in lung adenocarcinoma, endometrial carcinoma, and cancers of unknown primary, independent of clinical covariates and genetic ancestry. Obesity is therefore a putative driver of etiologic heterogeneity across cancers.

Surgical outcomes of cytoreductive nephrectomy in patients receiving systemic immunotherapy for advanced renal cell carcinoma.

PURPOSE: The use of systemic immune checkpoint blockade before surgery is increasing in patients with metastatic renal cell carcinoma, however, the safety and feasibility of performing consolidative cytoreductive nephrectomy after the administration of systemic therapy are not well described. PATIENTS AND METHODS: A retrospective review of patients undergoing nephrectomy was performed using our prospectively maintained institutional database. Patients who received preoperative systemic immunotherapy were identified, and the risk of postoperative complications were compared to those who underwent surgery without upfront systemic treatment. Perioperative characteristics and surgical complications within 90 days following surgery were recorded. RESULTS: Overall, we identified 220 patients who underwent cytoreductive nephrectomy from April 2015 to December 2022, of which 46 patients (21%) received systemic therapy before undergoing surgery. Unadjusted rates of surgical complications included 20% (n = 35) in patients who did not receive upfront systemic therapy and 20% (n = 9) in those who received upfront systemic immunotherapy. In our propensity score analysis, there was no statistically significant association between receipt of upfront immunotherapy and 90-day surgical complications [odds ratio (OR): 1.82, 95% confidence interval (CI): 0.59-5.14; P = 0.3]. This model, however, demonstrated an association between receipt of upfront immunotherapy and an increased odds of requiring a blood transfusion [OR: 4.53, 95% CI: 1.83-11.7; P = 0.001]. CONCLUSION: In our cohort, there was no significant difference in surgical complications among patients who received systemic therapy before surgery compared to those who did not receive upfront systemic therapy. Cytoreductive nephrectomy is safe and with low rates of complications following the use of systemic therapy.

Nivolumab plus ipilimumab in advanced salivary gland cancer: a phase 2 trial.

Salivary gland cancers (SGCs) are rare, aggressive cancers without effective treatments when metastasized. We conducted a phase 2 trial evaluating nivolumab (nivo, anti-PD-1) and ipilimumab (ipi, anti-CTLA-4) in 64 patients with metastatic SGC enrolled in two histology-based cohorts (32 patients each): adenoid cystic carcinoma (ACC; cohort 1) and other SGCs (cohort 2). The primary efficacy endpoint (≥4 objective responses) was met in cohort 2 (5/32, 16%) but not in cohort 1 (2/32, 6%). Treatment safety/tolerability and progression-free survival (PFS) were secondary endpoints. Treatment-related adverse events grade ≥3 occurred in 24 of 64 (38%) patients across both cohorts, and median PFS was 4.4 months (95% confidence interval (CI): 2.4, 8.3) and 2.2 months (95% CI: 1.8, 5.3) for cohorts 1 and 2, respectively. We present whole-exome, RNA and T cell receptor (TCR) sequencing data from pre-treatment and on-treatment tumors and immune cell flow cytometry and TCR sequencing from peripheral blood at serial timepoints. Responding tumors universally demonstrated clonal expansion of pre-existing T cells and mutational contraction. Responding ACCs harbored neoantigens, including fusion-derived neoepitopes, that induced T cell responses ex vivo. This study shows that nivo+ipi has limited efficacy in ACC, albeit with infrequent, exceptional responses, and that it could be promising for non-ACC SGCs, particularly salivary duct carcinomas. ClinicalTrials.gov identifier: NCT03172624 .

Adverse pathologic features impact survival outcomes for small renal masses following nephrectomy.

PURPOSE: While most small renal masses (SRM) < 4 cm have an excellent prognosis following resection, the impact of adverse T3a pathologic features on oncologic outcomes of SRMs remains unclear. We sought to compare clinical outcomes for surgically resected pT3a versus pT1a SRMs at our institution. MATERIALS AND METHODS: We retrospectively reviewed records of patients who underwent radical or partial nephrectomy (RN, PN) for renal tumors <4 cm at our institution between 2010 and 2020. We compared features and outcomes of pT3a vs pT1a SRMs. Continuous and categorical variables were compared using Student's t and Pearson's chi-squared tests, respectively. Postoperative outcomes of interest including overall, cancer-specific, and recurrence-free survival (OS, CSS, and RFS) were analyzed using Kaplan-Meier method, Cox proportional hazard regression, and competing risk analysis. Analyses were performed using R statistical package (R Foundation, v4.0). RESULTS: We identified 1,837 patients with malignant SRMs. Predictors of postoperative pT3a upstaging included higher renal score, larger tumor size, and presence of radiologic features concerning for T3a disease (odds ratio [OR] = 5.45, 95% confidence interval [CI] 3.92-7.59, P < 0.001). On univariable modeling, pT3a SRMs had higher positive margin rates (9.6% vs 4.1%, P < 0.001), worse OS (hazard ratio [HR] = 2.9, 95% CI 1.6-5.3, P = 0.002), RFS (HR 9.32, 95% CI 2-40.1, P = 0.003), and CSS (HR = 3.6, 95% CI 1.5-8.2, P = 0.003). On multivariable modeling, pT3a status remained associated with worse RFS (HR = 2.7, 95% CI 1.04-7, P = 0.04), but not OS (HR 1.6, 95% CI = 0.83-3.1, P = 0.2); multivariable modeling was deferred for CSS due to low event rates. CONCLUSIONS: Adverse T3a pathologic features portend worse outcomes for SRMs, highlighting the crucial role of pre-operative planning and case selection. These patients have relatively poor prognosis, and should be monitored more closely and counseled for consideration of adjuvant therapy or clinical trials.

Novel Genetic Subtypes of Urothelial Carcinoma With Differential Outcomes on Immune Checkpoint Blockade.

PURPOSE: Immune checkpoint blockade (ICB) therapy has significantly improved clinical outcomes in bladder cancer. Identification of correlates of benefit is critical to select appropriate therapy for individual patients. METHODS: To reveal genetic variables associated with benefit from ICB, we performed whole-exome sequencing on tumor specimens from 88 patients with advanced bladder cancer treated with ICB. RESULTS: We identified several genetic factors that correlated with progression-free and overall survival after ICB therapy including ARID1A mutation, tumor mutational burden, intratumoral heterogeneity, the ratio of nonsynonymous to synonymous mutations in the immunopeptidome (immune dN/dS), and tumor cell purity. In addition, we noted that neutrophil-to-lymphocyte ratio and smoking history were negatively associated with overall survival. These genetic characteristics define four molecular subtypes demonstrating differential sensitivity to ICB. We validated the association of these four subtypes with clinical benefit from ICB in an independent cohort (IMvigor210). Finally, we showed that these molecular subtypes also correlate with outcome, although with distinct relationships, among patients not treated with ICB using The Cancer Genome Atlas (TCGA) bladder cancer cohort. Using parallel RNA sequencing data, the subtypes were also shown to correlate with immune infiltration and inflammation, respectively, in the IMvigor210 and TCGA cohorts. CONCLUSION: Together, our study defines molecular subgroups of bladder cancer that influence benefit from ICB.

Genomic heterogeneity as a barrier to precision oncology in urothelial cancer.

Precision oncology relies on the accurate molecular characterization of individual patients with cancer at the time of treatment initiation. However, tumor molecular profiles are not static, and cancers continually evolve because of ongoing mutagenesis and clonal selection. Here, we performed genomic analyses of primary tumors, metastases, and plasma collected from individual patients to define the concordance of actionable genomic alterations and to identify drivers of metastatic disease progression. We observed a high degree of discordance of actionable genomic alterations, with 23% discordant between primary and metastatic disease sites. Among chromatin-modifying genes, ARID1A mutations, when discordant, were exclusive to the metastatic tumor samples. Our findings indicate that the high degree of lesion-to-lesion genomic heterogeneity may be a barrier to precision oncology approaches for bladder cancer and that circulating tumor DNA profiling may be preferred to tumor sequencing for a subset of patients.

FOXA1 repression drives lineage plasticity and immune heterogeneity in bladder cancers with squamous differentiation.

Cancers arising from the bladder urothelium often exhibit lineage plasticity with regions of urothelial carcinoma adjacent to or admixed with regions of divergent histomorphology, most commonly squamous differentiation. To define the biologic basis for and clinical significance of this morphologic heterogeneity, here we perform integrated genomic analyses of mixed histology bladder cancers with separable regions of urothelial and squamous differentiation. We find that squamous differentiation is a marker of intratumoral genomic and immunologic heterogeneity in patients with bladder cancer and a biomarker of intrinsic immunotherapy resistance. Phylogenetic analysis confirms that in all cases the urothelial and squamous regions are derived from a common shared precursor. Despite the presence of marked genomic heterogeneity between co-existent urothelial and squamous differentiated regions, no recurrent genomic alteration exclusive to the urothelial or squamous morphologies is identified. Rather, lineage plasticity in bladder cancers with squamous differentiation is associated with loss of expression of FOXA1, GATA3, and PPARG, transcription factors critical for maintenance of urothelial cell identity. Of clinical significance, lineage plasticity and PD-L1 expression is coordinately dysregulated via FOXA1, with patients exhibiting morphologic heterogeneity pre-treatment significantly less likely to respond to immune checkpoint inhibitors.

Genetic Ancestry Correlates with Somatic Differences in a Real-World Clinical Cancer Sequencing Cohort.

Accurate ancestry inference is critical for identifying genetic contributors of cancer disparities among populations. Although methods to infer genetic ancestry have historically relied upon genome-wide markers, the adaptation to targeted clinical sequencing panels presents an opportunity to incorporate ancestry inference into routine diagnostic workflows. We show that global ancestral contributions and admixture of continental populations can be quantitatively inferred using markers captured by the MSK-IMPACT clinical panel. In a pan-cancer cohort of 45,157 patients, we observed differences by ancestry in the frequency of somatic alterations, recapitulating known associations and revealing novel associations. Despite the comparable overall prevalence of driver alterations by ancestry group, the proportion of patients with clinically actionable alterations was lower for African (30%) compared with European (33%) ancestry. Although this result is largely explained by population-specific cancer subtype differences, it reveals an inequity in the degree to which different populations are served by existing precision oncology interventions. SIGNIFICANCE: We performed a comprehensive analysis of ancestral associations with somatic mutations in a real-world pan-cancer cohort, including >5,000 non-European individuals. Using an FDA-authorized tumor sequencing panel and an FDA-recognized oncology knowledge base, we detected differences in the prevalence of clinically actionable alterations, potentially contributing to health care disparities affecting underrepresented populations. This article is highlighted in the In This Issue feature, p. 2483.

Inherited Germline Cancer Susceptibility Gene Variants in Individuals with Non-Muscle-Invasive Bladder Cancer.

PURPOSE: Identification of inherited germline variants can guide personalized cancer screening, prevention, and treatment. Pathogenic and likely pathogenic (P/LP) germline variants in cancer predisposition genes are frequent among patients with locally advanced or metastatic urothelial carcinoma, but their prevalence and significance in patients with non-muscle-invasive bladder cancer (NMIBC), the most common form of urothelial carcinoma, is understudied. EXPERIMENTAL DESIGN: Germline analysis was conducted on paired tumor/normal sequencing results from two distinct cohorts of patients initially diagnosed with NMIBC. Associations between clinicopathologic features and clinical outcomes with the presence of P/LP germline variants in ≥76 hereditary cancer predisposition genes were analyzed. RESULTS: A similar frequency of P/LP germline variants were seen in our two NMIBC cohorts [12% (12/99) vs. 8.7% (10/115), P = 0.4]. In the combined analysis, P/LP germline variants were found only in patients with high-grade NMIBC (22/163), but none of the 46 patients with low-grade NMIBC (13.5% vs. 0%, P = 0.005). Fifteen (9.2%) patients with high-grade NMIBC had P/LP variants in DNA damage response genes, most within the nucleotide excision repair (ERCC2/3) and homologous recombination repair (BRCA1, NBN, RAD50) pathways. Contrary to prior reports in patients with NMIBC not receiving Bacillus Calmette-Guerin (BCG), P/LP germline variants were not associated with worse recurrence-free or progression-free survival in patients treated with BCG or with risk of developing upper tract urothelial carcinoma. CONCLUSIONS: Our results support offering germline counseling and testing for all patients with high-grade bladder cancer, regardless of initial tumor stage. Therapeutic strategies that target impaired DNA repair may benefit patients with high-grade NMIBC.

Long-term Outcomes of Local and Metastatic Small Cell Carcinoma of the Urinary Bladder and Genomic Analysis of Patients Treated With Neoadjuvant Chemotherapy.

INTRODUCTION: Small cell carcinoma of the bladder (SCCB) is a rare variant of bladder cancer with poor outcomes. We evaluated long-term outcomes of nonmetastatic (M0) and metastatic (M1) SCCB and correlated pathologic response with genomic alterations of patients treated with neoadjuvant chemotherapy (NAC). PATIENTS AND METHODS: Clinical history and pathology samples from SCCB patients diagnosed at our institution were reviewed. RESULTS: One hundred and ninety-nine SCCB patients were identified. (M0: 147 [74%]; M1: 52 [26%]). Among M0 patients, 108 underwent radical cystectomy (RC) (NAC: 71; RC only: 23; adjuvant chemotherapy: 14); 14 received chemoradiotherapy; the rest received chemotherapy alone or no cancer-directed therapy. RC-only patients had a median follow-up of 9.1 years, and median disease-free survival (DFS) and overall survival (OS) were 1.1 and 1.2 years, respectively. NAC patients had pathologic response (

Clinical and Genomic Characterization of Bladder Carcinomas With Glandular Phenotype.

PURPOSE: To compare oncologic outcomes and genomic alteration profiles in patients with bladder and urachal adenocarcinoma, urothelial carcinoma (UC) with glandular differentiation, and UC, not otherwise specified (NOS) undergoing surgical resection, with emphasis on response to systemic therapy. METHODS: We identified patients with bladder cancer with glandular variants who underwent surgical resection at Memorial Sloan Kettering from 1995 to 2018 (surgical cohort) and/or patients who had tumor sequencing using a targeted next-generation sequencing platform (genomics cohort). Pathologic complete and partial response rates to neoadjuvant chemotherapy (NAC) and recurrence-free and cancer-specific survival were measured. Alteration frequencies between histologic subtypes were compared. RESULTS: Thirty-seven patients with bladder adenocarcinoma, 46 with urachal adenocarcinoma, 84 with UC with glandular differentiation, and 1,049 with UC, NOS comprised the surgical cohort. Despite more advanced disease in patients with bladder and urachal adenocarcinoma, no significant differences in recurrence or cancer-specific survival by histology were observed after adjusting for stage. In patients with UC with glandular differentiation, NAC resulted in partial (≤ pT1N0) and complete (pT0N0) responses in 28% and 17%, respectively. Bladder and urachal adenocarcinoma genomic profiles resembled colorectal adenocarcinoma with frequent TP53, KRAS, and PIK3CA alterations while the genomic profile of UC with glandular differentiation more closely resembled UC, NOS. Limitations include retrospective nature of analysis and small numbers of nonurothelial histology specimens. CONCLUSION: The genomic profile of bladder adenocarcinomas resembled colorectal adenocarcinomas, whereas UC with glandular differentiation more closely resembled UC, NOS. Differences in outcomes among patients with glandular bladder cancer variants undergoing surgical resection were largely driven by differences in stage. Cisplatin-based NAC demonstrated activity in UC with glandular differentiation, suggesting NAC should be considered for this histologic variant.

A Targetable Myeloid Inflammatory State Governs Disease Recurrence in Clear-Cell Renal Cell Carcinoma.

It is poorly understood how the tumor immune microenvironment influences disease recurrence in localized clear-cell renal cell carcinoma (ccRCC). Here we performed whole-transcriptomic profiling of 236 tumors from patients assigned to the placebo-only arm of a randomized, adjuvant clinical trial for high-risk localized ccRCC. Unbiased pathway analysis identified myeloid-derived IL6 as a key mediator. Furthermore, a novel myeloid gene signature strongly correlated with disease recurrence and overall survival on uni- and multivariate analyses and is linked to TP53 inactivation across multiple data sets. Strikingly, effector T-cell gene signatures, infiltration patterns, and exhaustion markers were not associated with disease recurrence. Targeting immunosuppressive myeloid inflammation with an adenosine A2A receptor antagonist in a novel, immunocompetent, Tp53-inactivated mouse model significantly reduced metastatic development. Our findings suggest that myeloid inflammation promotes disease recurrence in ccRCC and is targetable as well as provide a potential biomarker-based framework for the design of future immuno-oncology trials in ccRCC. SIGNIFICANCE: Improved understanding of factors that influence metastatic development in localized ccRCC is greatly needed to aid accurate prediction of disease recurrence, clinical decision-making, and future adjuvant clinical trial design. Our analysis implicates intratumoral myeloid inflammation as a key driver of metastasis in patients and a novel immunocompetent mouse model. This article is highlighted in the In This Issue feature, p. 2221.

Neoadjuvant Atezolizumab With Gemcitabine and Cisplatin in Patients With Muscle-Invasive Bladder Cancer: A Multicenter, Single-Arm, Phase II Trial.

PURPOSE: Neoadjuvant gemcitabine and cisplatin (GC) followed by radical cystectomy (RC) is standard for patients with muscle-invasive bladder cancer (MIBC). On the basis of the activity of atezolizumab (A) in metastatic BC, we tested neoadjuvant GC plus A for MIBC. METHODS: Eligible patients with MIBC (cT2-T4aN0M0) received a dose of A, followed 2 weeks later by GC plus A every 21 days for four cycles followed 3 weeks later by a dose of A before RC. The primary end point was non-muscle-invasive downstaging to < pT2N0. RESULTS: Of 44 enrolled patients, 39 were evaluable. The primary end point was met, with 27 of 39 patients (69%) < pT2N0, including 16 (41%) pT0N0. No patient with < pT2N0 relapsed and four (11%) with ≥ pT2N0 relapsed with a median follow-up of 16.5 months (range: 7.0-33.7 months). One patient refused RC and two developed metastatic disease before RC; all were considered nonresponders. The most common grade 3-4 adverse event (AE) was neutropenia (n = 16; 36%). Grade 3 immune-related AEs occurred in five (11%) patients with two (5%) requiring systemic steroids. The median time from last dose of chemotherapy to surgery was 7.8 weeks (range: 5.1-17 weeks), and no patient failed to undergo RC because of AEs. Four of 39 (10%) patients had programmed death-ligand 1 (PD-L1)-positive tumors and were all < pT2N0. Of the patients with PD-L1 low or negative tumors, 23 of 34 (68%) achieved < pT2N0 and 11 of 34 (32%) were ≥ pT2N0 (P = .3 for association between PD-L1 and < pT2N0). CONCLUSION: Neoadjuvant GC plus A is a promising regimen for MIBC and warrants further study. Patients with < pT2N0 experienced improved relapse-free survival. The PD-L1 positivity rate was low compared with published data, which limits conclusions regarding PD-L1 as a predictive biomarker.

A High-Content Screen for C/EBPα Expression Identifies Novel Therapeutic Agents in Dedifferentiated Liposarcoma.

PURPOSE: Dedifferentiated liposarcoma (DDLS), one of the most common and aggressive sarcomas, infrequently responds to chemotherapy. DDLS survival and growth depend on underexpression of C/EBPα, a tumor suppressor and transcriptional regulator controlling adipogenesis. We sought to screen and prioritize candidate drugs that increase C/EBPα expression and may therefore serve as differentiation-based therapies for DDLS. EXPERIMENTAL DESIGN: We screened known bioactive compounds for the ability to restore C/EBPα expression and inhibit proliferation selectively in two DDLS cell lines but not in normal adipose-derived stem cells (ASC). Selected hits' activity was validated, and the mechanism of the most potent, SN-38, was investigated. The in vivo efficacy of irinotecan, the prodrug of SN-38, was evaluated in DDLS xenograft models. RESULTS: Of 3,119 compounds, screen criteria were met by 19. Validation experiments confirmed the DDLS selectivity of deguelin, emetine, and SN-38 and showed that they induce apoptosis in DDLS cells. SN-38 had the lowest IC50 (approximately 10 nmol/L), and its pro-apoptotic effects were countered by knockdown of CEBPA but not of TP53. Irinotecan significantly inhibited tumor growth at well-tolerated doses, induced nuclear expression of C/EBPα, and inhibited HIF1α expression in DDLS patient-derived and cancer cell line xenograft models. In contrast, doxorubicin, the most common treatment for nonresectable DDLS, reduced tumor growth by 30% to 50% at a dose that caused weight loss. CONCLUSIONS: This high-content screen revealed potential treatments for DDLS. These include irinotecan, which induces apoptosis of DDLS cells in a C/EBPα-dependent, p53-independent manner, and should be clinically evaluated in patients with advanced DDLS.

Identifying prognostic pairwise relationships among bacterial species in microbiome studies.

In recent literature, the human microbiome has been shown to have a major influence on human health. To investigate this impact, scientists study the composition and abundance of bacterial species, commonly using 16S rRNA gene sequencing, among patients with and without a disease or condition. Methods for such investigations to date have focused on the association between individual bacterium and an outcome, and higher-order pairwise relationships or interactions among bacteria are often avoided due to the substantial increase in dimension and the potential for spurious correlations. However, overlooking such relationships ignores the environment of the microbiome, where there is dynamic cooperation and competition among bacteria. We present a method for identifying and ranking pairs of bacteria that have a differential dichotomized relationship across outcomes. Our approach, implemented in an R package PairSeek, uses the stability selection framework with data-driven dichotomized forms of the pairwise relationships. We illustrate the properties of the proposed method using a published oral cancer data set and a simulation study.

Somatic mutations as preoperative predictors of metastases in patients with localized clear cell renal cell carcinoma - An exploratory analysis.

OBJECTIVE: Recurrent genomic alterations in clear cell renal cell carcinoma (ccRCC) have been associated with treatment outcomes; however, current preoperative predictive models do not include known genetic predictors. We aimed to explore the value of common somatic mutations in the preoperative prediction of metastatic disease among patients treated for localized ccRCC. MATERIALS AND METHODS: After obtaining institutional review board approval, data of 254 patients with localized ccRCC treated between 2005 and 2015 who underwent genetic sequencing was collected. The mutation status of VHL, PBRM1, SETD2, BAP1 and KDM5C were evaluated in the nephrectomy tumor specimen, which served as a proxy for biopsy mutation status. The Raj et al. preoperative nomogram was used to predict the 12-year metastatic free probability (MFP). The study outcome was MFP; the relationship between MFP and mutation status was evaluated with Cox-regression models adjusting for the preoperative nomogram variables (age, gender, incidental presentation, lymphadenopathy, necrosis, and size). RESULTS: The study cohort included 188 males (74%) and 66 females (26%) with a median age of 58 years. VHL mutations were present in 152/254 patients (60%), PBRM1 in 91/254 (36%), SETD2 in 32/254 (13%), BAP1 in 19/254 (8%), and KDM5C in 19/254 (8%). Median follow-up for survivors was 8.1 years. Estimated 12-year MFP was 70% (95% CI: 63%-75%). On univariable analysis SETD2 (HR: 3.30), BAP1 (HR: 2.44) and PBRM1 (HR: 1.78) were significantly associated with a higher risk of metastases. After adjusting for known preoperative predictors in the existing nomogram, SETD2 mutations remained associated with a higher rate of metastases after nephrectomy (HR: 2.09, 95% CI: 1.19-3.67, P = 0.011). CONCLUSION: In the current exploratory analysis, SETD2 mutations were significant predictors of MFP among patients treated for localized ccRCC. Our findings support future studies evaluating genetic alterations in preoperative renal biopsy samples as potential predictors of treatment outcome.