Three- and Seven-month Prostate-specific Antigen Levels as Prognostic Markers for Overall Survival in Metastatic Hormone-sensitive Prostate Cancer: Results from SWOG S1216, a Phase 3 Randomized Trial of Androgen Deprivation Plus Orteronel or Bicalutamide.

BACKGROUND: A robust decrease in prostate-specific antigen (PSA) in response to androgen deprivation therapy (ADT) has been evaluated as a prognostic factor in patients with metastatic hormone-sensitive prostate cancer (mHSPC) since 2006, but the treatment of mHSPC has since evolved to include intensified therapy. OBJECTIVE: We assessed the association of PSA levels at 3 (PSA-3mo) and 7 (PSA-7mo) mo with overall survival (OS) in patients with mHSPC treated with ADT combined with either bicalutamide or orteronel in the S1216 phase 3 clinical trial. DESIGN, SETTING, AND PARTICIPANTS: PSA responses to treatment of patients in the S1216 trial were categorized as: complete response (CR) if PSA was ≤0.2 ng/ml, partial response if PSA was >0.2 and ≤4 ng/ml, and no response (NR) if PSA was >4 ng/ml. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: A Cox analysis (adjusted for treatment arm and three stratification factors: performance status, severity of disease, and early vs late induction) was used for OS association. While PSA-7mo association was a prespecified objective, PSA-3mo association was also evaluated. RESULTS AND LIMITATIONS: A total of 1251 and 1231 patients from the S1216 study were evaluable for PSA-3mo and PSA-7mo, respectively. A PSA-7mo CR was associated with improved OS compared with NR (HR: 0.20; p < 0.0001). A PSA-3mo CR showed a similar association to NR (HR: 0.34; p < 0.0001). The association of a PSA response with survival did not differ by treatment arm at either time point. CONCLUSIONS: The PSA-3mo and PSA-7mo responses were strongly associated with OS; taken with other emerging prognostic biomarkers, these markers may allow for early identification of patients at the highest risk of death, aid with counseling in clinical practice, and permit design of future clinical trials targeting these patients. PATIENT SUMMARY: A low prostate-specific antigen level at 3 or 7 mo after starting treatment for metastatic hormone-sensitive prostate cancer predicts longer survival regardless of the first treatment given with androgen deprivation therapy.

NCCN Guidelines® Insights: Kidney Cancer, Version 2.2024.

The NCCN Guidelines for Kidney Cancer provide multidisciplinary recommendations for diagnostic workup, staging, and treatment of patients with renal cell carcinoma (RCC). These NCCN Guidelines Insights focus on the systemic therapy options for patients with advanced RCC and summarize the new clinical data evaluated by the NCCN panel for the recommended therapies in Version 2.2024 of the NCCN Guidelines for Kidney Cancer.

Markers of bone metabolism and overall survival in men with bone-metastatic hormone sensitive prostate cancer (HSPC): A subset analysis of SWOG S1216, a phase III trial of androgen deprivation with or without orteronel.

BACKGROUND: Circulating biomarkers of bone metabolism are significantly associated with overall survival (OS) in men with advanced prostate cancer. In the SWOG S1216 phase III trial, we showed that elevated bone biomarkers are significantly associated with an increased risk of death in hormone-sensitive prostate cancer (HSPC) regardless of the status of bone metastases, identifying three risk groups with differential OS outcomes based on bone biomarker status. Here we report the association of bone biomarkers with OS in men with HSPC and documented skeletal metastases as part of a planned subset analysis of S1216. METHODS: Bone resorption [C-telopeptide (CTx); Pyridinoline (PYD)] and bone formation markers [C-terminal collagen propeptide (CICP); bone alkaline phosphatase (BAP)] were assessed in blood from men with bone metastatic HSPC. Patients were randomly divided into training (n = 238) and validation (n = 475) sets. In the training set, recursive partitioning that maximizes discrimination of OS was used to identify the dichotomous cut-point for each biomarker and for a combination of biomarker split points to define prognostic groups. In the validation set, Cox proportional hazards models were used to assess the impact of biomarkers on OS, adjusted for patient and tumor characteristics. RESULTS: Of 1279 men, 713 had both baseline bone metastases and evaluable bone biomarkers. Patient characteristics were similar between the overall population and the subset with bone metastases. Elevated levels of CICP, CTX, and PYD were strongly prognostic for OS. Hazard ratios (95% CI) for OS adjusted for treatment arm and baseline clinical variables were: BAP-1.31 (0.93, 1.84), p = 0.12; CICP-1.58 (1.09, 2.29), p < 0.02; CTx - 1.55 (1.12, 2.15), p = 0.008; and PYD-1.66 (1.27, 2.217), p = 0.0002. There was no evidence of interaction between elevated biomarkers and treatment (all p > 0.2). Recursive partitioning algorithms identified four groups of patients with differential OS outcomes based on bone biomarkers, adjusted for baseline clinical variables, with median OS ranging from 2.3 years (highest risk group) to 7.5 years (lowest risk group). CONCLUSIONS: In this planned S1216 subset analysis of men with HSPC and bone metastases, elevated serum markers of bone metabolism were significantly associated with worse OS. Bone biomarker levels alone and in combination with patient and tumor characteristics identify unique subsets of men with differential OS outcomes. GOV IDENTIFIER: NCT01809691.

Bone Biomarkers and Subsequent Survival in Men with Hormone-sensitive Prostate Cancer: Results from the SWOG S1216 Phase 3 Trial of Androgen Deprivation Therapy with or Without Orteronel.

BACKGROUND: Bone biomarkers are strongly prognostic for overall survival (OS) in men with castration-resistant prostate cancer but not fully established for hormone-sensitive prostate cancer (HSPC). OBJECTIVE: Bone biomarkers in HSPC were prospectively evaluated as part of a phase 3 study of androgen deprivation therapy ± the CYP17 inhibitor orteronel. DESIGN, SETTING, AND PARTICIPANTS: Patients were randomly divided into training (n = 316) and validation (n = 633) sets. Recursive partitioning and Cox proportional hazard models were employed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Bone resorption (C-telopeptide and pyridinoline) and bone formation markers (C-terminal collagen propeptide and bone alkaline phosphatase) were assessed from patient sera. RESULTS AND LIMITATIONS: Of 1279 men, 949 had evaluable baseline bone biomarkers. Optimal cutoffs were identified to define elevated levels of each of the four biomarkers (all p < 0.05) that were associated with worse OS. After adjusting for clinical risk factors in the validation set, elevated bone biomarkers were statistically significantly associated with an increased risk of death (hazard ratios ranging from 1.37 to 1.92). Recursive partitioning algorithms applied to the training set identified three risk groups (low, intermediate, and poor) with differential OS outcomes (median OS: 8.2, 5.1, and 2.1 yr, respectively) based on combinations of bone biomarkers. These results were confirmed in the validation set. CONCLUSIONS: In men with HSPC initiating androgen deprivation therapy, bone biomarkers are strongly and independently prognostic for OS. Bone biomarker levels alone or in combination with clinical covariates identify unique subsets of men with differential OS outcomes. These results validate the clinical value of bone biomarker assessment in the HSPC state, extending bone biomarker utility beyond the castration-resistant state. PATIENT SUMMARY: In men with newly diagnosed metastatic prostate cancer, high levels of bone turnover biomarkers are associated with a shorter lifespan.

Use of recombinant microRNAs as antimetabolites to inhibit human non-small cell lung cancer.

During the development of therapeutic microRNAs (miRNAs or miRs), it is essential to define their pharmacological actions. Rather, miRNA research and therapy mainly use miRNA mimics synthesized in vitro. After experimental screening of unique recombinant miRNAs produced in vivo, three lead antiproliferative miRNAs against human NSCLC cells, miR-22-3p, miR-9-5p, and miR-218-5p, were revealed to target folate metabolism by bioinformatic analyses. Recombinant miR-22-3p, miR-9-5p, and miR-218-5p were shown to regulate key folate metabolic enzymes to inhibit folate metabolism and subsequently alter amino acid metabolome in NSCLC A549 and H1975 cells. Isotope tracing studies further confirmed the disruption of one-carbon transfer from serine to folate metabolites by all three miRNAs, inhibition of glucose uptake by miR-22-3p, and reduction of serine biosynthesis from glucose by miR-9-5p and -218-5p in NSCLC cells. With greater activities to interrupt NSCLC cell respiration, glycolysis, and colony formation than miR-9-5p and -218-5p, recombinant miR-22-3p was effective to reduce tumor growth in two NSCLC patient-derived xenograft mouse models without causing any toxicity. These results establish a common antifolate mechanism and differential actions on glucose uptake and metabolism for three lead anticancer miRNAs as well as antitumor efficacy for miR-22-3p nanomedicine, which shall provide insight into developing antimetabolite RNA therapies.

Race and Treatment Outcomes in Patients With Metastatic Castration-Sensitive Prostate Cancer: A Secondary Analysis of the SWOG 1216 Phase 3 Trial.

Importance: Black patients present with more aggressive disease and experience higher mortality than White patients with prostate cancer. Race and social determinants of health influence prostate cancer-specific mortality and overall survival (OS); however, in a previous trial, Black patients did not have inferior outcomes compared with White patients, possibly because of equitable access to care available in a clinical trial setting. Objective: To compare differences in survival outcomes of patients with metastatic castration-sensitive prostate cancer (mCSPC) by race in a phase 3 trial with a large proportion of Black patients. Design, Setting, and Participants: This secondary analysis of patient-level data of a prospective phase 3 randomized clinical trial included patients with newly diagnosed mCSPC enrolled between March 1, 2013, and July 15, 2017. Analysis was conducted between December 2022 and February 2023. Interventions: Patients receiving androgen deprivation therapy were randomized (1:1) to receive either orteronel 300 mg orally twice daily (experimental group) or bicalutamide 50 mg orally daily (control group). Main Outcomes and Measures: OS, with progression-free survival (PFS) as a secondary end point. Results: Among 1313 participants, 135 (10%) identified as Black and 1077 (82%) as White, with an equal racial distribution between groups. Black patients were younger (median [IQR] age, 65.8 [60-70] vs 68.4 [62.5-74.1] years; P = .001) and had a higher median (IQR) baseline prostate-specific antigen response rate than White patients (54.7 [19.8-222.0] vs 26.7 [9.2-96.0] ng/mL; P < .001). At a median follow-up of 4.9 years, Black and White patients had similar median PFS (2.3 years; 95% CI, 1.8-1.4 years vs 2.9 years; 95% CI, 2.5-3.3 years; P = .71) and OS (5.5 years; 95% CI, 4.8-NR vs 6.3 years; 95% CI, 5.7-NR; P = .65). The multivariable analysis confirmed similar PFS and OS after adjusting for known prognostic factors. No interaction between race and treatment was observed. Conclusions and Relevance: In this secondary analysis of a randomized clinical trial studying androgen deprivation therapy with first- or second-generation androgen receptor pathway inhibitors, both Black and White patients demonstrated similar OS and PFS. Equitable access to care may reduce historical differences in outcomes between Black and White patients with advanced prostate cancer. Trial Registration: ClinicalTrials.gov Identifier: NCT01809691.

Adjuvant everolimus after surgery for renal cell carcinoma (EVEREST): a double-blind, placebo-controlled, randomised, phase 3 trial.

BACKGROUND: Patients undergoing resection of renal cell carcinoma are at risk of disease relapse. We evaluated the effectiveness of the mammalian target of rapamycin inhibitor everolimus administered after surgery. METHODS: In this randomised, double-blind, phase 3 trial, we enrolled adults with histologically confirmed renal cell carcinoma who had undergone a full surgical resection and were at intermediate-high or very high risk of recurrence at 398 academic and community institution centres in the USA. After nephrectomy, patients were randomly assigned (1:1) via a central web-based application using a dynamic balancing algorithm to receive 10 mg oral everolimus daily or placebo for 54 weeks. The primary endpoint was recurrence-free survival. Efficacy analyses included all eligible, randomly assigned patients; safety analysis included all patients who received treatment. This trial is registered with ClinicalTrials.gov, NCT01120249 and is closed to new participants. FINDINGS: Between April 1, 2011, and Sept 15, 2016, a total of 1545 patients were randomly assigned to receive everolimus (n=775) or placebo (n=770), of whom 755 assigned to everolimus and 744 assigned to placebo were eligible for inclusion in the efficacy analysis. With a median follow-up of 76 months (IQR 61-92), recurrence-free survival was longer with everolimus than with placebo (5-year recurrence-free survival 67% [95% CI 63-70] vs 63% [60-67]; stratified log-rank p=0·050; stratified hazard ratio [HR] 0·85, 95% CI 0·72-1·00; p=0·051) but did not meet the prespecified p value for statistical significance of 0·044. Recurrence-free survival was longer with everolimus than with placebo in the very-high-risk group (HR 0·79, 95% CI 0·65-0·97; p=0·022) but not in the intermediate-high-risk group (0·99, 0·73-1·35; p=0·96). Grade 3 or higher adverse events occurred in 343 (46%) of 740 patients who received everolimus and 79 (11%) of 723 who received placebo. INTERPRETATION: Postoperative everolimus did not improve recurrence-free survival compared with placebo among patients with renal cell carcinoma at high risk of recurrence after nephrectomy. These results do not support the adjuvant use of everolimus for renal cell carcinoma after surgery. FUNDING: US National Institutes of Health, National Cancer Institute, National Clinical Trials Network, Novartis Pharmaceuticals Corporation, and The Hope Foundation.

The Genomic and Epigenomic Landscape of Double-Negative Metastatic Prostate Cancer.

Systemic targeted therapy in prostate cancer is primarily focused on ablating androgen signaling. Androgen deprivation therapy and second-generation androgen receptor (AR)-targeted therapy selectively favor the development of treatment-resistant subtypes of metastatic castration-resistant prostate cancer (mCRPC), defined by AR and neuroendocrine (NE) markers. Molecular drivers of double-negative (AR-/NE-) mCRPC are poorly defined. In this study, we comprehensively characterized treatment-emergent mCRPC by integrating matched RNA sequencing, whole-genome sequencing, and whole-genome bisulfite sequencing from 210 tumors. AR-/NE- tumors were clinically and molecularly distinct from other mCRPC subtypes, with the shortest survival, amplification of the chromatin remodeler CHD7, and PTEN loss. Methylation changes in CHD7 candidate enhancers were linked to elevated CHD7 expression in AR-/NE+ tumors. Genome-wide methylation analysis nominated Krüppel-like factor 5 (KLF5) as a driver of the AR-/NE- phenotype, and KLF5 activity was linked to RB1 loss. These observations reveal the aggressiveness of AR-/NE- mCRPC and could facilitate the identification of therapeutic targets in this highly aggressive disease. SIGNIFICANCE: Comprehensive characterization of the five subtypes of metastatic castration-resistant prostate cancer identified transcription factors that drive each subtype and showed that the double-negative subtype has the worst prognosis.

ATR Inhibition in Advanced Urothelial Carcinoma.

The ataxia telangiectasia and Rad3-related (ATR) checkpoint kinase 1 (CHK1) pathway is intricately involved in protecting the integrity of the human genome by suppressing replication stress and repairing DNA damage. ATR is a promising therapeutic target in cancer cells because its inhibition could lead to an accumulation of damaged DNA preventing further replication and division. ATR inhibition is being studied in multiple types of cancer, including advanced urothelial carcinoma where there remains an unmet need for novel therapies to improve outcomes. Herein, we review preclinical and clinical data evaluating 4 ATR inhibitors as monotherapy or in combination with chemotherapy. The scope of this review is focused on contemporary studies evaluating the application of this novel therapy in advanced urothelial carcinoma.

Novel inhibition of AKR1C3 and androgen receptor axis by PTUPB synergizes enzalutamide treatment in advanced prostate cancer.

Castration-resistant prostate cancer (CRPC) is the main driving force of mortality in prostate cancer patients. Among the parameters contributing to the progression of CRPC and treatment failure, elevation of the steroidogenic enzyme AKR1C3 and androgen receptor variant 7 (AR-V7) are frequently reported. The AKR1C3/AR-V7 complex has been recognized as a major driver for drug resistance in advanced prostate cancer. Herein we report that the level of AKR1C3 is reciprocally regulated by the full-length androgen receptor (AR-FL) through binding to the distal enhancer region of the AKR1C3 gene. A novel function of PTUPB in AKR1C3 inhibition was discovered and PTUPB showed more effectiveness than indomethacin and celecoxib in suppressing AKR1C3 activity and CRPC cell growth. PTUPB synergizes with enzalutamide treatment in tumor suppression and gene signature regulation. Combination treatments with PTUPB and enzalutamide provide benefits by blocking AR/AR-V7 signaling, which inhibits the growth of castration relapsed VCaP xenograft tumors and patient-derived xenograft organoids. Targeting of the ARK1C3/AR/AR-V7 axis with PTUPB and enzalutamide may overcome drug resistance to AR signaling inhibitors in advanced prostate cancer.

Randomized Trial of Olaparib With or Without Cediranib for Metastatic Castration-Resistant Prostate Cancer: The Results From National Cancer Institute 9984.

PURPOSE: Cediranib, a pan-vascular endothelial growth factor receptor inhibitor, suppresses expression of homologous recombination repair (HRR) genes and increases sensitivity to poly-(ADP-ribose) polymerase inhibition in preclinical models. We investigated whether cediranib combined with olaparib improves the clinical outcomes of patients with prostate cancer. METHODS: Patients with progressive metastatic castration-resistant prostate cancer (mCRPC) were randomly assigned 1:1 to arm A: cediranib 30 mg once daily plus olaparib 200 mg twice daily or arm B: olaparib 300 mg twice daily alone. The primary end point was radiographic progression-free survival (rPFS) in the intention-to-treat patients. The secondary end points were rPFS in patients with HRR-deficient and HRR-proficient mCRPC. RESULTS: In the intention-to-treat set of 90 patients, median rPFS was 8.5 (95% CI, 5.4 to 12.0) and 4.0 (95% CI, 3.2 to 8.5) months in arms A and B, respectively. Cediranib/olaparib significantly improved rPFS versus olaparib alone (hazard ratio [HR], 0.617; 95% CI, 0.392 to 0.969; P = .0359). Descriptive analyses showed a median rPFS of 10.6 (95% CI, 5.9 to not assessed [NA]) and 3.8 (95% CI, 2.33 to NA) months (HR, 0.64; 95% CI, 0.272 to 1.504) among patients with HRR-deficient mCRPC, and 13.8 (95% CI, 3.3 to NA) and 11.3 (95% CI, 3.8 to NA) months (HR, 0.98; 95% CI, 0.321 to 2.988) among patients with BRCA2-mutated mCRPC in arms A and B, respectively. The incidence of grades 3-4 adverse events was 61% and 18% in arms A and B, respectively. CONCLUSION: Cediranib combined with olaparib improved rPFS compared with olaparib alone in men with mCRPC. This combination was associated with an increased incidence of grades 3-4 adverse events. BRCA2-mutated subgroups treated with olaparib with or without cediranib were associated with a numerically longer median rPFS.

EphrinB2 Inhibition and Pembrolizumab in Metastatic Urothelial Carcinoma.

PURPOSE: Patients with metastatic urothelial carcinoma have poor prognosis after failure of standard first-line chemotherapy. Immune check point programmed death 1-programmed death ligand 1 antibodies have low response rates and thus there exists a major unmet need. MATERIALS AND METHODS: In this phase II trial, patients with metastatic urothelial carcinoma that recurred or progressed after platinum-based chemotherapy received soluble EphB4-human serum albumin (sEphB4-HSA) in combination with pembrolizumab. The primary end points were tolerability and overall survival (OS). The secondary end points were progression-free survival (PFS), objective response rate (ORR), duration of response, and toxicity. The expression of sEphB4-HSA target EphrinB2 was correlated with outcomes. RESULTS: Seventy patients were enrolled. The median follow up was 22.9 months (range, 1.3-54.7). The regimen had acceptable toxicity. In the intent-to-treat analysis (N = 70), the median OS was 14.6 months (95% CI, 9.2 to 21.5). Twenty-six (37%) patients had an objective response (95% CI, 26 to 48). The median PFS was 4.1 (95% CI, 1.5 to 5.7) months. Forty-six (66%) patients expressed EphrinB2, and among them, the median OS was 21.5 months (95% CI, 12.4 to not reached), the ORR was 52% (95% CI, 37 to 67), including a complete response rate of 24% (11 of 46; 95% CI, 12 to 36). The median PFS was 5.7 (95% CI, 2.7 to 27.9) months. Response was maintained at 6, 12, and 24 months in 88%, 74%, and 69% of the patients, respectively. CONCLUSION: The combination of sEphB4-HSA and pembrolizumab appears synergistic with improved OS and ORR compared with historical data for programmed death 1/programmed death ligand 1 monotherapy.

The Impact of Facility Surgical Caseload Volumes on Survival Outcomes in Patients Undergoing Radical Cystectomy.

The role of surgical experience and its impact on the survival requires further investigation. A cohort of patients undergoing radical cystectomy or anterior pelvic exenteration for localized bladder cancer between 2006 and 2013 at 1143 facilities across the United States was identified using the National Cancer Database and analyzed. Using overall survival (OS) as the primary outcome, the relationship between facility annual caseload (FAC) and facility annual surgical caseload (FASC) for those undergoing curative surgery was examined. Four volume groups (VG) depending on caseload using both FAC and FASC were defined. These included VG1: below 50th percentile, VG2: 50th−74th percentile, VG3: 75th−89th percentile, and VG4: 90th and above. Between 2006 and 2013, 27,272 patients underwent surgery for localized bladder cancer. The median OS was 59.66 months (95% CI: 57.79−61.77). OS improved significantly as caseload increased. The unadjusted median OS difference between VG1 and VG4 was 15.35 months (64.3 vs. 48.95 months, HR 1.19 95% CI: 1.13−1.25, p < 0.001) for FAC. This figure was 19.84 months (66.89 vs. 47.05 months, HR 1.25 95% CI: 1.18−1.32, p < 0.0001) for FASC. This analysis revealed a significant and clinically important survival advantage for curative bladder cancer surgery at highly experienced centers.

The 5-Hydroxymethylcytosine Landscape of Prostate Cancer.

Analysis of DNA methylation is a valuable tool to understand disease progression and is increasingly being used to create diagnostic and prognostic clinical biomarkers. While conversion of cytosine to 5-methylcytosine (5mC) commonly results in transcriptional repression, further conversion to 5-hydroxymethylcytosine (5hmC) is associated with transcriptional activation. Here we perform the first study integrating whole-genome 5hmC with DNA, 5mC, and transcriptome sequencing in clinical samples of benign, localized, and advanced prostate cancer. 5hmC is shown to mark activation of cancer drivers and downstream targets. Furthermore, 5hmC sequencing revealed profoundly altered cell states throughout the disease course, characterized by increased proliferation, oncogenic signaling, dedifferentiation, and lineage plasticity to neuroendocrine and gastrointestinal lineages. Finally, 5hmC sequencing of cell-free DNA from patients with metastatic disease proved useful as a prognostic biomarker able to identify an aggressive subtype of prostate cancer using the genes TOP2A and EZH2, previously only detectable by transcriptomic analysis of solid tumor biopsies. Overall, these findings reveal that 5hmC marks epigenomic activation in prostate cancer and identify hallmarks of prostate cancer progression with potential as biomarkers of aggressive disease. SIGNIFICANCE: In prostate cancer, 5-hydroxymethylcytosine delineates oncogene activation and stage-specific cell states and can be analyzed in liquid biopsies to detect cancer phenotypes. See related article by Wu and Attard, p. 3880.

A Genomically and Clinically Annotated Patient-Derived Xenograft Resource for Preclinical Research in Non-Small Cell Lung Cancer.

Patient-derived xenograft (PDX) models are an effective preclinical in vivo platform for testing the efficacy of novel drugs and drug combinations for cancer therapeutics. Here we describe a repository of 79 genomically and clinically annotated lung cancer PDXs available from The Jackson Laboratory that have been extensively characterized for histopathologic features, mutational profiles, gene expression, and copy-number aberrations. Most of the PDXs are models of non-small cell lung cancer (NSCLC), including 37 lung adenocarcinoma (LUAD) and 33 lung squamous cell carcinoma (LUSC) models. Other lung cancer models in the repository include four small cell carcinomas, two large cell neuroendocrine carcinomas, two adenosquamous carcinomas, and one pleomorphic carcinoma. Models with both de novo and acquired resistance to targeted therapies with tyrosine kinase inhibitors are available in the collection. The genomic profiles of the LUAD and LUSC PDX models are consistent with those observed in patient tumors from The Cancer Genome Atlas and previously characterized gene expression-based molecular subtypes. Clinically relevant mutations identified in the original patient tumors were confirmed in engrafted PDX tumors. Treatment studies performed in a subset of the models recapitulated the responses expected on the basis of the observed genomic profiles. These models therefore serve as a valuable preclinical platform for translational cancer research. SIGNIFICANCE: Patient-derived xenografts of lung cancer retain key features observed in the originating patient tumors and show expected responses to treatment with standard-of-care agents, providing experimentally tractable and reproducible models for preclinical investigations.

Transcriptional profiling of matched patient biopsies clarifies molecular determinants of enzalutamide-induced lineage plasticity.

The androgen receptor (AR) signaling inhibitor enzalutamide (enza) is one of the principal treatments for metastatic castration-resistant prostate cancer (CRPC). Several emergent enza clinical resistance mechanisms have been described, including lineage plasticity in which the tumors manifest reduced dependency on the AR. To improve our understanding of enza resistance, herein we analyze the transcriptomes of matched biopsies from men with metastatic CRPC obtained prior to treatment and at progression (n = 21). RNA-sequencing analysis demonstrates that enza does not induce marked, sustained changes in the tumor transcriptome in most patients. However, three patients' progression biopsies show evidence of lineage plasticity. The transcription factor E2F1 and pathways linked to tumor stemness are highly activated in baseline biopsies from patients whose tumors undergo lineage plasticity. We find a gene signature enriched in these baseline biopsies that is strongly associated with poor survival in independent patient cohorts and with risk of castration-induced lineage plasticity in patient-derived xenograft models, suggesting that tumors harboring this gene expression program may be at particular risk for resistance mediated by lineage plasticity and poor outcomes.