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.

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.

Preoperative nomogram predicting 12-year probability of metastatic renal cancer - evaluation in a contemporary cohort

OBJECTIVES

Preoperative models, based on patient and tumor characteristics, predict risk for adverse outcomes after nephrectomy. Changes in renal tumor characteristics over the last decades, warrant further evaluation using contemporary cohorts. We aimed to validate a previously published preoperative nomogram predicting 12-year metastasis-free probability after nephrectomy for localized renal tumors in a contemporary cohort.

PATIENTS AND METHODS

After obtaining institutional review board approval, data of 1,760 patients who underwent nephrectomy for a localized renal mass between 2005 and 2011 were reviewed. Preoperative images were evaluated for the presence of tumor necrosis, lymphadenopathy, and tumor size. The study outcome was metastatic-free probability. Model discrimination was assessed with Gönen and Heller's concordance probability estimate, and calibration was evaluated.

RESULTS

The cohort included 1,102 male and 658 female patients with a median age of 60 years. Most patients presented incidentally (84%). On imaging, 3% had evidence of lymphadenopathy, 55% had necrosis and median tumor diameter was 3.7 cm (interquartile range [IQR]: 2.5, 5.5). Median follow-up in non-metastatic patients was 7.7 years (IQR: 5.3, 9.7). Estimated 12-year metastatic-free probability was 88% (86%-90%). The model showed strong discrimination (concordance probability estimate [CPE]: 0.77), and fair calibration. The time-dependent receiver operating characteristic (ROC) curves showed strong discrimination at all-time points and the area under the curve (AUC) for year 12 was 0.83 (95% Confidence Interval: 0.78-0.89).

CONCLUSIONS

We validated the preoperative nomogram of 12-year metastasis-free probability in a contemporary cohort despite different tumor characteristics. Future studies should evaluate the role of preoperative risk stratification in patient selection for neoadjuvant treatment.

Abstract B20: Characterization of tumor mutational landscape in smokers and nonsmokers with urothelial carcinoma

Introduction and Objectives: Smoking is a major risk factor for development of bladder cancer. It has been previously shown that smoking-related and non-smoking-related cancers have characteristic mutational signatures. Hypothesizing that somatic alterations differ between smokers and nonsmokers with urothelial carcinoma, we used next-generation sequencing to evaluate for differences in genomic alterations between these two groups of patients.

Methods: We identified in our prospectively maintained institutional database all patients with urothelial carcinoma whose tumors underwent next-generation sequencing using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) assay. A panel of genes previously reported by The Cancer Genome Atlas (TCGA) as being commonly mutated in bladder cancer was chosen for analysis.

Results: A total of 1,044 samples from 968 patients were included in the analysis. Seven hundred eighty-five (85%) of the samples represented bladder tumors and 259 (25%) of the samples represented tumors of the upper tract. Patients with smoking history comprised 66% of the cohort. The most frequently altered genes in active or former smokers and never smokers were TERT promoter (55% and 60%), TP53 (43% and 41%), KDM6A (30% and 26%), and FGFR3 (27% and 26%).

Conclusions: Mutational profiling of urothelial tumors in this large cohort of patients showed high incidence of genomic alterations consistent with prior studies. The frequency of alterations in these genes was similar between smokers and nonsmokers. To further understand smoking-related mutational process, we are examining mutational signatures and differences in genomic alterations as a function of smoking intensity exposure.

Citation Format: Aleksandra Walasek, Nima Almassi, Min Yuen Teo, Samuel Funt, Nikolaus Schultz, Guido Dalbagni, Wenhu Hu, Hikmat Al-Ahmadie, Dean F Bajorin, Jonathan E Rosenberg, Gopakumar Iyer, Bernard H. Bochner, David B. Solit, Eugene J. Pietzak. Characterization of tumor mutational landscape in smokers and nonsmokers with urothelial carcinoma [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2019 May 18-21; Denver, CO. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(15_Suppl):Abstract nr B20.

Phosphatidic acid drives mTORC1 lysosomal translocation in the absence of amino acids

Mammalian target of rapamycin complex 1 (mTORC1) promotes cell growth and proliferation in response to nutrients and growth factors. Amino acids induce lysosomal translocation of mTORC1 via the Rag GTPases. Growth factors activate Ras homolog enriched in brain (Rheb), which in turn activates mTORC1 at the lysosome. Amino acids and growth factors also induce the phospholipase D (PLD)-phosphatidic acid (PA) pathway, required for mTORC1 signaling through mechanisms that are not fully understood. Here, using human and murine cell lines, along with immunofluorescence, confocal microscopy, endocytosis, PLD activity, and cell viability assays, we show that exogenously supplied PA vesicles deliver mTORC1 to the lysosome in the absence of amino acids, Rag GTPases, growth factors, and Rheb. Of note, pharmacological or genetic inhibition of endogenous PLD prevented mTORC1 lysosomal translocation. We observed that precancerous cells with constitutive Rheb activation through loss of tuberous sclerosis complex subunit 2 (TSC2) exploit the PLD-PA pathway and thereby sustain mTORC1 activation at the lysosome in the absence of amino acids. Our findings indicate that sequential inputs from amino acids and growth factors trigger PA production required for mTORC1 translocation and activation at the lysosome.