RPL22 is a tumor suppressor in MSI-high cancers and a key splicing regulator of MDM4

Microsatellite instability high (MSI-H) tumors are malignant tumors that, despite harboring a high mutational burden, often have intact TP53. One of the most frequent mutations in MSI-H tumors is a frameshift mutation in RPL22, a ribosomal protein. Here, we identified RPL22 as a modulator of MDM4 splicing through an alternative splicing switch in exon 6. RPL22 loss increases MDM4 exon 6 inclusion, cell proliferation, and augments resistance to the MDM inhibitor Nutlin-3a. RPL22 represses expression of its paralog, RPL22L1, by mediating the splicing of a cryptic exon corresponding to a truncated transcript. Therefore, damaging mutations in RPL22 drive oncogenic MDM4 induction and reveal a common splicing circuit in MSI-H tumors that may inform therapeutic targeting of the MDM4-p53 axis and oncogenic RPL22L1 induction.

Racial disparity in the genomics of precision oncology of prostate cancer

BACKGROUND

Significant racial disparities in prostate cancer incidence and mortality have been reported between African American Men (AAM), who are at increased risk for prostate cancer, and European American Men (EAM). In most of the studies carried out on prostate cancer, this population is underrepresented. With the advancement of genome-wide association studies, several genetic predictor models of prostate cancer risk have been elaborated, as well as numerous studies that identify both germline and somatic mutations with clinical utility.

RECENT FINDINGS

Despite significant advances, the AAM population continues to be underrepresented in genomic studies, which can limit generalizability and potentially widen disparities. Here we outline racial disparities in currently available genomic applications that are used to estimate the risk of individuals developing prostate cancer and to identify personalized oncology treatment strategies. While the incidence and mortality of prostate cancer are different between AAM and EAM, samples from AAM remain to be unrepresented in different studies.

CONCLUSION

This disparity impacts the available genomic data on prostate cancer. As a result, the disparity can limit the predictive utility of the genomic applications and may lead to the widening of the existing disparities. More studies with substantially higher recruitment and engagement of African American patients are necessary to overcome this disparity.

Club-like cells in proliferative inflammatory atrophy of the prostate

Club cells are a type of bronchiolar epithelial cell that serve a protective role in the lung and regenerate damaged lung epithelium. Single-cell RNA sequencing (scRNA-seq) of young adult human prostate and urethra identified cell populations in the prostatic urethra and collecting ducts similar in morphology and transcriptomic profile to lung club cells. We further identified club cell-like epithelial cells by scRNA-seq of prostate peripheral zone tissues. Here, we aimed to identify and spatially localize club cells in situ in the prostate, including in the peripheral zone. We performed chromogenic RNA in situ hybridization for five club cell markers (CP, LTF, MMP7, PIGR, SCGB1A1) in a series of (1) nondiseased organ donor prostate and (2) radical prostatectomy specimens from individuals with prostate cancer. We report that expression of club cell genes in the peripheral zone is associated with inflammation and limited to luminal epithelial cells classified as intermediate cells in proliferative inflammatory atrophy (PIA). Club-like cells were enriched in radical prostatectomy specimens compared to nondiseased prostates and associated with high-grade prostate cancer. We previously reported that luminal epithelial cells in PIA can rarely harbor oncogenic TMPRSS2:ERG (ERG+) gene fusions, and we now demonstrate that club cells are present in association with ERG+ PIA that is transitioning to early adenocarcinoma. Finally, prostate epithelial organoids derived from prostatectomy specimens demonstrate that club-like epithelial cells can be established in organoids and are sensitive to anti-androgen-directed treatment in vitro in terms of decreased androgen signaling gene expression signatures compared to basal or hillock cells. Overall, our study identifies a population of club-like cells in PIA and proposes that these cells play an analogous role to that of club cells in bronchiolar epithelium. Our results further suggest that inflammation drives lineage plasticity in the human prostate and that club cells in PIA may be prone to oncogenic transformation. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Profiling the Somatic Mutational Landscape of Breast Tumors from Hispanic/Latina Women Reveals Conserved and Unique Characteristics

Somatic mutational profiling is increasingly being used to identify potential targets for breast cancer. However, limited tumor-sequencing data from Hispanic/Latinas (H/L) are available to guide treatment. To address this gap, we performed whole-exome sequencing (WES) and RNA sequencing on 146 tumors and WES of matched germline DNA from 140 H/L women in California. Tumor intrinsic subtype, somatic mutations, copy-number alterations, and expression profiles of the tumors were characterized and compared with data from tumors of non-Hispanic White (White) women in The Cancer Genome Atlas (TCGA). Eight genes were significantly mutated in the H/L tumors including PIK3CA, TP53, GATA3, MAP3K1, CDH1, CBFB, PTEN, and RUNX1; the prevalence of mutations in these genes was similar to that observed in White women in TCGA. Four previously reported Catalogue of Somatic Mutations in Cancer (COSMIC) mutation signatures (1, 2, 3, 13) were found in the H/L dataset, along with signature 16 that has not been previously reported in other breast cancer datasets. Recurrent amplifications were observed in breast cancer drivers including MYC, FGFR1, CCND1, and ERBB2, as well as a recurrent amplification in 17q11.2 associated with high KIAA0100 gene expression that has been implicated in breast cancer aggressiveness. In conclusion, this study identified a higher prevalence of COSMIC signature 16 and a recurrent copy-number amplification affecting expression of KIAA0100 in breast tumors from H/L compared with White women. These results highlight the necessity of studying underrepresented populations.

SIGNIFICANCE

Comprehensive characterization of genomic and transcriptomic alterations in breast tumors from Hispanic/Latina patients reveals distinct genetic alterations and signatures, demonstrating the importance of inclusive studies to ensure equitable care for patients. See related commentary by Schmit et al., p. 2443.

Understanding inequities in precision oncology diagnostics

Advances in molecular diagnostics have enabled the identification of targetable driver pathogenic variants, forming the basis of precision oncology care. However, the adoption of new technologies, such as next-generation sequencing (NGS) panels, can exacerbate healthcare disparities. Here, we summarize data on use patterns of advanced biomarker testing, highlight the disparities in both accessing NGS testing and using this data to match patients to appropriate personalized therapies and propose multidisciplinary strategies to address inequities looking forward.

Transcriptomic profiling and genomic rearrangement landscape of Nigerian prostate cancer

BACKGROUND

Men of African ancestry have disproportionately high incidence rates of prostate cancer (PCa) and have high mortality rates. While there is evidence for a higher genetic predisposition for incidence of PCa in men of African ancestry compared to men of European ancestry, there have been few transcriptomic studies on PCa in men of African ancestry in the African continent.

OBJECTIVE

We performed transcriptomic profiling and fusion analysis on bulk RNA sequencing (RNA-seq) samples from 24 Nigerian PCa patients to investigate the transcriptomic and genomic rearrangement landscape of PCa in Nigerian men.

DESIGN

Bulk RNA-seq was performed on 24 formalin-fixed paraffin-embeded (FFPE) prostatectomy specimens of Nigerian men. Transcriptomic analysis was performed on 11 high-quality samples. Arriba Fusion and STAR Fusion were used for fusion detection.

RESULTS

4/11 (36%) of the samples harbored an erythroblast transformation-specific (ETS) fusion event; 1/11 (9%) had a TMPRSS2-ERG fusion; 2/11 had a TMPRSS2-ETV5 fusion, and 1/11 had a SLC45A3-SKIL fusion. Hierarchical clustering of normalized and mean-centered gene expression showed clustering of fusion positive samples. Furthermore, we developed gene set signatures for Nigerian PCa based on fusion events. By projecting the cancer genome atlas prostate adenocarcinoma (TCGA-PRAD) bulk RNA-seq data set onto the transcriptional space defined by these signatures derived from Nigerian PCa patients, we identified a positive correlation between the Nigerian fusion signature and fusion positive samples in the TCGA-PRAD data set.

CONCLUSIONS

Less frequent ETS fusion events other than TMPRSS2-ERG such as TMPRSS2-ETV5 and non-ETS fusion events such as SLC45A3-SKIL may be more common in PCa in Nigerian men. This study provides useful working transcriptomic signatures that characterize oncogenic states representative of specific gene fusion events in PCa from Nigerian men.

Cancer Demographics and Time-to-Care in Belize

BACKGROUND

Belize is a middle-income Caribbean country with poorly described cancer epidemiology and no comprehensive cancer care capacity. In 2018, GO, Inc., a US-based NGO, partnered with the Ministry of Health and the national hospital in Belize City to create the first public oncology clinic in the country. Here, we report demographics from the clinic and describe time intervals to care milestones to allow for public health targeting of gaps.

PATIENTS AND METHODS

Using paper charts and a mobile health platform, we performed a retrospective chart review at the Karl Heusner Memorial Hospital (KHMH) clinic from 2018 to 2022.

RESULTS

During this time period, 465 patients with cancer presented to the clinic. Breast cancer (28%) and cervical cancer (12%) were most common. Most patients (68%) presented with stage 3 or 4 disease and were uninsured (78%) and unemployed (79%). Only 21% of patients ever started curative intent treatment. Median time from patient-reported symptoms to a biopsy or treatment was 130 and 189 days. For the most common cancer, breast, similar times were seen at 140 and 178 days. Time intervals at the clinic: <30 days from initial visit to biopsy (if not previously performed) and <30 days to starting chemotherapy.

CONCLUSION

This study reports the first clinic-based cancer statistics for Belize. Many patients have months between symptom onset and treatment. In this setting, the clinic has built infrastructure allowing for minimal delays in care despite an underserved population. This further affirms the need for infrastructure investment and early detection programs to improve outcomes in Belize.

Circulating tumor DNA and homologous recombination deficiency in bone-predominant mCRPC prior to radium-223 therapy

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Background: Radium-223 (Ra-223) is a bone-seeking alpha emitter that induces double-stranded DNA breaks, and the homologous recombination (HR) pathway is critical for repairing these breaks. While prior studies suggested that metastatic castrate-resistant prostate cancers (mCRPC) patients (pts) with HR-deficient (HRD+) tumors may be more likely to benefit from Ra-223, obtaining tissue for next generation sequencing to identify HRD+ is challenging in pts with bone-predominant disease. We hypothesized that circulating tumor DNA (ctDNA) would allow for broader identification of HRD+ to assess association with clinical outcomes in a real-world cohort. Methods: We identified 135 mCRPC pts treated with Ra-223 at our institution between 2013 and 2021. Pts who initiated another anti-tumor therapy within 60 days of Ra-223 treatment were excluded; pts continuing hormonal agents initiated >60 days prior were included. ctDNA isolated from pre-treatment plasma underwent ultra-low-pass whole genome sequencing to estimate tumor fraction (TF). Additionally, targeted panel sequencing using an institutional prostate cancer-specific panel of 319 genes with duplex sequencing (utilizing unique molecular identifiers) for error suppression was used to identify germline or somatic deleterious alterations in HR pathway genes. The primary outcome was association between HRD status and completion of fewer than 6 cycles (as a proxy for early clinical progression), assessed using logistic regression. Results: The median age was 61 (IQR, 56-67) years, median pretreatment prostate-specific antigen (PSA) level was 26.2 (IQR, 8.1-84.1) ng/mL, and median TF was 4% (IQR, 3-6%). 97% of pts (n=131) previously received a novel antiandrogen, and 63% (n=85) received prior taxane. 17% (n=23) were HRD+, and 59% (n=80) completed 6 cycles of Ra-223. On multivariable analysis, HRD+ was associated with decreased likelihood of completing 6 cycles compared to HRD- (adjusted odds ratio [AOR] 0.16, 95% confidence interval [CI] 0.05-0.48, P=0.001). 22% (n=5) of HRD+ pts completed 6 cycles compared to 67% (n=75) of HRD- pts. Additional factors associated with decreased likelihood of completing 6 cycles included a higher pretreatment TF (AOR 0.69, 95% CI, 0.48-0.97, P=0.034) and prior taxane use (AOR 0.41, 95% CI, 0.18-0.91, P=0.028), but not pretreatment PSA ( P=0.574). Conclusions: Targeted panel sequencing with error suppression from ctDNA identified HRD+ in mCRPC pts with bone-predominant disease and low median TF at a similar frequency as reported from tissue. In our cohort, HRD+ was prognostic of early clinical progression with Ra-223. Further work is in progress to understand the association of other ctDNA-derived features, including assessment of genomic signatures and transcriptional binding sites, in the setting of Ra-223 therapy. DF/HCC IRB protocol 18-135.

Defining cellular population dynamics at single-cell resolution during prostate cancer progression

Advanced prostate malignancies are a leading cause of cancer-related deaths in men, in large part due to our incomplete understanding of cellular drivers of disease progression. We investigate prostate cancer cell dynamics at single-cell resolution from disease onset to the development of androgen independence in an in vivo murine model. We observe an expansion of a castration-resistant intermediate luminal cell type that correlates with treatment resistance and poor prognosis in human patients. Moreover, transformed epithelial cells and associated fibroblasts create a microenvironment conducive to pro-tumorigenic immune infiltration, which is partially androgen responsive. Androgen-independent prostate cancer leads to significant diversification of intermediate luminal cell populations characterized by a range of androgen signaling activity, which is inversely correlated with proliferation and mRNA translation. Accordingly, distinct epithelial populations are exquisitely sensitive to translation inhibition, which leads to epithelial cell death, loss of pro-tumorigenic signaling, and decreased tumor heterogeneity. Our findings reveal a complex tumor environment largely dominated by castration-resistant luminal cells and immunosuppressive infiltrates.

The CIC-ERF co-deletion underlies fusion-independent activation of ETS family member, ETV1, to drive prostate cancer progression

Human prostate cancer can result from chromosomal rearrangements that lead to aberrant ETS gene expression. The mechanisms that lead to fusion-independent ETS factor upregulation and prostate oncogenesis remain relatively unknown. Here, we show that two neighboring transcription factors, Capicua (CIC) and ETS2 repressor factor (ERF), which are co-deleted in human prostate tumors can drive prostate oncogenesis. Concurrent CIC and ERF loss commonly occur through focal genomic deletions at chromosome 19q13.2. Mechanistically, CIC and ERF co-bind the proximal regulatory element and mutually repress the ETS transcription factor, ETV1. Targeting ETV1 in CIC and ERF-deficient prostate cancer limits tumor growth. Thus, we have uncovered a fusion-independent mode of ETS transcriptional activation defined by concurrent loss of CIC and ERF.

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.

Single-cell analysis of hepatoblastoma identifies tumor signatures that predict chemotherapy susceptibility using patient-specific tumor spheroids

Pediatric hepatoblastoma is the most common primary liver cancer in infants and children. Studies of hepatoblastoma that focus exclusively on tumor cells demonstrate sparse somatic mutations and a common cell of origin, the hepatoblast, across patients. In contrast to the homogeneity these studies would suggest, hepatoblastoma tumors have a high degree of heterogeneity that can portend poor prognosis. In this study, we use single-cell transcriptomic techniques to analyze resected human pediatric hepatoblastoma specimens, and identify five hepatoblastoma tumor signatures that may account for the tumor heterogeneity observed in this disease. Notably, patient-derived hepatoblastoma spheroid cultures predict differential responses to treatment based on the transcriptomic signature of each tumor, suggesting a path forward for precision oncology for these tumors. In this work, we define hepatoblastoma tumor heterogeneity with single-cell resolution and demonstrate that patient-derived spheroids can be used to evaluate responses to chemotherapy.

Updated demographics at the only public oncology clinic in Belize

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Background: Belize is a middle-income Caribbean country without comprehensive cancer care capacity and poorly described cancer epidemiology. In 2020, we reported some of the first cancer demographics from the country. This was made possible by a capacity building partnership with the only public oncology clinic in the country at Karl Heusner Memorial Hospital (KHMH). Here we provide an update on demographic trends at this clinic. Methods: We performed a retrospective chart review of all available patient data at the KHMH clinic from December 2020 to December 2021. This was compared to data from the clinic’s founding in 2018 through its first 12 months. Results: From December 2020 through December 2021, the clinic saw 332 patients, an increase of 141% from the 236 patients seen over the first 12-month period of the clinic. In 2021, 250 (75%) patients had a confirmed pathologic diagnosis of cancer, with 78 (23%) remaining under clinical suspicion. This is in comparison to 63% of patients with a pathologic diagnosis in 2018. H&E staining alone remained the only publicly available pathologic service. Patients were predominantly female (67%) with a median age of 54 (Range: 2-95). The most common histologies (n = 332) were breast (29%), cervical (11%), colorectal (8%), prostate (4%), gastric (4%), and lung (3%). Of patients with histologically confirmed cancer, 221 (66%) were able to be fully staged. Patients predominantly presented with later stage disease (25% Stage III, 34% Stage IV). At the end of 2021, out of all patients tracked longitudinally over the year (n = 332), 24% remained in need of full diagnostic assessment, 34% were on curative treatment (predominantly cytotoxic chemotherapy), 22% were under surveillance, and 18% were receiving palliative chemotherapy or best supportive care due to advanced disease. This is in comparison to 2018, when there was no capacity to administer chemotherapy at KHMH and patients were referred to either private clinics or out of the country. Conclusions: The burden of cancer in Belize is significant and diverse. Compared to 2018, in 2021, the number of patients seen at KHMH increased 141%, as did the percentage of patients with histologically confirmed cancer (120% increase). Chemotherapy treatment was made possible through procurement of a chemotherapeutic stock at KHMH due to key partnerships with the Belizean government, hospital administration, and crucially, the only medical oncologist in the nation. This has led to chemotherapy being available at a public clinic in the country for the first time. Despite this progress, patients continue to present at late stages and many cannot access cancer care due to limited resources, cost, and low public awareness. This further affirms the need for infrastructure investment and early detection programs to improve cancer outcomes in Belize.

Breast cancer characteristics and time to chemotherapy initiation in Belize

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Background: Breast cancer is the most common cancer in low and middle-income countries. Belize, a middle-income country in the Caribbean with significant inequality, lacks a national screening program and has limited treatment capacity. There are no studies describing breast cancer characteristics in Belize in the available literature. We collected data from the sole public oncology clinic in the country, established in 2018 at Karl Heusner Memorial Hospital (KHMH), to describe the characteristics of breast cancer patients and establish baseline measurements of time to chemotherapy initiation for the curative intent treatment population; the aim being to identify potential areas for quality improvement. Methods: We performed a retrospective chart review of available patient data from December 2020 to December 2021. We examined the time from a patient’s initial visit at KHMH until chemotherapy initiation (TCI) in the neoadjuvant setting with patients stratified by stage. Significant outliers (predominantly patients with misclassified data or those with private access to physicians and therapeutics) were excluded. Results: The clinic provided care for 80 patients with biopsy-proven breast cancer between December 2020 to December 2021. Patients were 97% female with a median age of 55 (Range: 34-81). For stageable patients (n=75), 33% presented with clinically localized disease, 49% with locally advanced, and 17% with recurrent or metastatic disease. Of the 51 patients on chemotherapy, 57% were receiving preoperative treatment, 31% were on adjuvant therapy, and 12% on palliative therapy. Patients not on therapy (n=29) at KHMH were either in surveillance, referred to a private cancer center, or deceased. Neoadjuvant TCI was calculated for 21 patients after the removal of outliers (n=5). The majority of these patients arrived at their initial clinic visit with a biopsy-proven diagnosis. Mean TCI for early stage disease was 49 days (n=7, 95% CI [9, 89]) and locally advanced disease was 36 days (n=14, 95% CI [12, 61]). Aggregate mean TCI was 40 days (n=21, 95% CI [19, 62]). Conclusions: In Belize, breast cancer affects younger women and patients present with later stages of disease than in high-income countries; however, time to chemotherapy initiation in a small sample of neoadjuvant patients at the Belizean clinic was comparable. Given the inherent limitations of small samples of data, additional investigation is needed to support these findings, as well as to delineate patient barriers to access and potential for improvements in clinic follow-up. Nevertheless, indications of a robust TCI call for further characterization of this newly established cancer clinic and its practices.

Efficacy of an educational comic book for HPV vaccination information in Nigeria

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Background: In Nigeria, cervical cancer is the second most common cancer in part due to disparities in education, access to screening, and access to treatment. In Nigeria, the HPV vaccine is planned for introduction into the public sector but will not be mandated. Given the preventable nature of the disease and need for public awareness, we developed an easy-to-understand teaching tool, the Global Oncology (GO) Comic Book focused on both general cancer education and about cervical cancer and HPV vaccination. Methods: The GO Comic Book is set in modern-day Lagos, Nigeria and aims to dispel myths and misconceptions associated with cancer in general and cervical cancer in particular. After developing the comic book, we developed a teaching guide and a plan for a pilot distribution of the comic book to students in Nigeria. In late 2019, GO and programmatic partners including the Clinton Health Access Initiative (CHAI), Cancer Education and Advocacy Foundation of Nigeria (CEAFON) and Panaramic Comics (based in Lagos, Nigeria) successfully conducted a pilot distribution of the GO Comic Book to nearly 5,000 students representing 18 junior secondary schools in Lagos and Rivers states. The comic books were distributed as part of 12 school assemblies which featured interactive, live-readings of the comic book by students and Nigerian physician volunteers. Pre-/post-tests with 9 questions were administered to a subset of the students (N = 202) to assess change in knowledge before and after the educational assemblies and data was analyzed using descriptive statistics. Results: The response rate of the 202 administered surveys was 98% (N = 198) with 193 female (97.5%) and 5 male (2.5%) respondents. Participants were an average of 11.2 years of age. All multiple-choice-type assessment items showed shifts to better-informed responses following the educational intervention. The item with the highest positive-percent change as assessed in the post survey queried: “what types of virus can cause cervical cancer?” (pre-test = 25.2%, post-test = 68.2%). The table below shows the cervical cancer related questions that were asked and the proportion of correct answers. Conclusions: The GO comic book in conjunction with school assemblies, improved the knowledge regarding cervical cancer causes and risk factors in Nigerian school children. Findings highlight the lack of knowledge regarding cervical cancer among the young population eligible for HPV vaccination, and describe an effective educational strategy in this setting.[Table: see text]

The Tabula Sapiens: A multiple-organ, single-cell transcriptomic atlas of humans

Molecular characterization of cell types using single-cell transcriptome sequencing is revolutionizing cell biology and enabling new insights into the physiology of human organs. We created a human reference atlas comprising nearly 500,000 cells from 24 different tissues and organs, many from the same donor. This atlas enabled molecular characterization of more than 400 cell types, their distribution across tissues, and tissue-specific variation in gene expression. Using multiple tissues from a single donor enabled identification of the clonal distribution of T cells between tissues, identification of the tissue-specific mutation rate in B cells, and analysis of the cell cycle state and proliferative potential of shared cell types across tissues. Cell type-specific RNA splicing was discovered and analyzed across tissues within an individual.

Implementation of a prostate cancer-specific targeted sequencing panel for credentialing of patient-derived cell lines and genomic characterization of patient samples

BACKGROUND

Primary and metastatic prostate cancers have low mutation rates and recurrent alterations in a small set of genes, enabling targeted sequencing of prostate cancer-associated genes as an efficient approach to characterizing patient samples (compared to whole-exome and whole-genome sequencing). For example, targeted sequencing provides a flexible, rapid, and cost-effective method for genomic assessment of patient-derived cell lines to evaluate fidelity to initial patient tumor samples.

METHODS

We developed a prostate cancer-specific targeted next-generation sequencing (NGS) panel to detect alterations in 62 prostate cancer-associated genes as well as recurring gene fusions with ETS family members, representing the majority of common alterations in prostate cancer. We tested this panel on primary prostate cancer tissues and blood biopsies from patients with metastatic prostate cancer. We generated patient-derived cell lines from primary prostate cancers using conditional reprogramming methods and applied targeted sequencing to evaluate the fidelity of these cell lines to the original patient tumors.

RESULTS

The prostate cancer-specific panel identified biologically and clinically relevant alterations, including point mutations in driver oncogenes and ETS family fusion genes, in tumor tissues from 29 radical prostatectomy samples. The targeted panel also identified genomic alterations in cell-free DNA and circulating tumor cells (CTCs) from patients with metastatic prostate cancer, and in standard prostate cancer cell lines. We used the targeted panel to sequence our set of patient-derived cell lines; however, no prostate cancer-specific mutations were identified in the tumor-derived cell lines, suggesting preferential outgrowth of normal prostate epithelial cells.

CONCLUSIONS

We evaluated a prostate cancer-specific targeted NGS panel to detect common and clinically relevant alterations (including ETS family gene fusions) in prostate cancer. The panel detected driver mutations in a diverse set of clinical samples of prostate cancer, including fresh-frozen tumors, cell-free DNA, CTCs, and cell lines. Targeted sequencing of patient-derived cell lines highlights the challenge of deriving cell lines from primary prostate cancers and the importance of genomic characterization to credential candidate cell lines. Our study supports that a prostate cancer-specific targeted sequencing panel provides an efficient, clinically feasible approach to identify genetic alterations across a spectrum of prostate cancer samples and cell lines.

Prostate Cancer in the Caribbean: A Baseline Assessment of Current Practices and Potential Needs

Afro-Caribbean men have a higher risk of prostate cancer than any other population of men in the world. However, the Caribbean is composed of a heterogenous group of healthcare systems located on small islands which makes population-based studies difficult to conduct and interpret. The aim of this review is to compile previously published data on the state of prostate cancer in Caribbean men and to highlight potential healthcare needs that can be addressed by public health efforts. We reviewed three databases and identified relevant papers that were subsequently searched by the authors. Peer-reviewed studies published in the English language after 2010 with a focus on prostate cancer diagnosis, management, and outcomes of Caribbean men were prioritized. Afro-Caribbean men were found to have a higher incidence and mortality rate compared to their counterparts. Misperception about the disease, lack of regional guidelines, and poor access to care are compounding factors that result in worse outcomes for these men compared to high-income nations. Urologists and oncologists in the region, while well-trained, are limited in number and in most cases do not offer newer treatment modalities. Overall, only a few island nations have cancer registries, and there remains a significant need for more population-based studies to assess guideline adherence and outcomes. Until further research and investment in the region is made, the disparity between the care received by Afro-Caribbean men and their counterparts will likely remain.

COVID-19 outcomes in patients with cancer: Findings from the University of California health system database

Background

The interaction between cancer diagnoses and COVID‐19 infection and outcomes is unclear. We leveraged a state‐wide, multi‐institutional database to assess cancer‐related risk factors for poor COVID‐19 outcomes.

Methods

We conducted a retrospective cohort study using the University of California Health COVID Research Dataset, which includes electronic health data of patients tested for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) at 17 California medical centers. We identified adults tested for SARS‐CoV‐2 from 2/1/2020–12/31/2020 and selected a cohort of patients with cancer. We obtained demographic, clinical, cancer type, and antineoplastic therapy data. The primary outcome was hospitalization within 30d after the first positive SARS‐CoV‐2 test. Secondary outcomes were SARS‐CoV‐2 positivity and severe COVID‐19 (intensive care, mechanical ventilation, or death within 30d after the first positive test). We used multivariable logistic regression to identify cancer‐related factors associated with outcomes.

Results

We identified 409,462 patients undergoing SARS‐CoV‐2 testing. Of 49,918 patients with cancer, 1781 (3.6%) tested positive. Patients with cancer were less likely to test positive (RR 0.70, 95% CI: 0.67–0.74, p < 0.001). Among the 1781 SARS‐CoV‐2‐positive patients with cancer, BCR/ABL‐negative myeloproliferative neoplasms (RR 2.15, 95% CI: 1.25–3.41, p = 0.007), venetoclax (RR 2.96, 95% CI: 1.14–5.66, p = 0.028), and methotrexate (RR 2.72, 95% CI: 1.10–5.19, p = 0.032) were associated with greater hospitalization risk. Cancer and therapy types were not associated with severe COVID‐19.

Conclusions

In this large, diverse cohort, cancer was associated with a decreased risk of SARS‐CoV‐2 positivity. Patients with BCR/ABL‐negative myeloproliferative neoplasm or receiving methotrexate or venetoclax may be at increased risk of hospitalization following SARS‐CoV‐2 infection. Mechanistic and comparative studies are needed to validate findings.

Biomarkers predictive of response to enfortumab vedotin (EV) treatment in advanced urothelial cancer (aUC)

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Background: EV is an antibody-drug conjugate which recently received full FDA approval for treatment-refractory aUC. Molecular biomarkers and characteristics of patients (pts) most likely to respond to EV therapy have not been well defined. Methods: We retrospectively identified all aUC pts treated with EV at our institution. Clinicopathologic, treatment and response data were abstracted from pt charts. Pts were considered responders to EV if they had a complete response on initial scans after 2-3 months of treatment, or were treated with EV for ≥ 6 months. Responders and non-responders were compared in terms of their molecular and clinical characteristics using Chi-squared test. Most common somatic alterations present in ≥10 pts ( TERTp, TP53, CDKN2A, CDKN2B) were also used to divide pts with available next-generation sequencing (NGS) results into groups with and without these alterations. Log rank test was used to determine differences in overall survival (OS) and progression free survival (PFS) among these groups. Results: Between 1/2020 and 8/2021 a total of 32 pts received EV and 28 had NGS data available with either FoundationOne (14 pts), UCSF500 (13 pts) or Strata (1). Median age was 69.5 years, 24 (75%) were male, 22 (69%) Caucasian, 22 (69%) had pure urothelial histology and 22 (69%) primary tumor location in the bladder. At EV start, 24 (75%) had visceral metastases (mets), 8 (25%) had liver mets, and 13 (41%) had bone mets. Median follow-up from EV start was 12.5 months (range 0.5-36); 20 (63%) pts received EV monotherapy, and 12 (37%) received EV as part of a combination regimen. Non-responders were more likely to have bone metastases (69% vs 21%, p<0.01), but were otherwise similar in baseline clinical characteristics to responders. TP53 alterations were enriched in responders relative to non-responders, whereas non-responders had more CDKN2B alterations (Table). Similar findings were seen in the subset of pts treated with EV monotherapy. Pts with TP53 alterations had longer OS (NR vs 17.0 months, p=0.06) and PFS (NR vs 6.6 months, p=0.04) relative to wild-type pts. Shorter PFS was seen in pts with CDKN2A (4.4 months vs NR, p=0.05) and CDKN2B (4.3 months vs NR, p=0.02) alterations, but no differences in OS were observed. Conclusions: In this retrospective cohort of aUC pts with available NGS data, presence of TP53 and absence of CDKN2A and CDKN2B alterations were associated with favorable responses and improved clinical outcomes with EV, suggesting they may be biomarkers of response to EV. These preliminary findings should be validated in larger cohorts.[Table: see text]

Serial stereotactic body radiation therapy for oligometastatic prostate cancer (PCa) detected by positron emission tomography (PET) imaging

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Background: Radiopharmaceuticals, including Ga-68-prostate specific membrane antigen (PSMA)-11, F-18-fluciclovine, and choline C-11, are increasingly used to stage and inform therapies for PCa. Stereotactic body radiation therapy (SBRT) to PET-detected oligometastatic PCa has been shown to improve progression free survival (PFS) compared to observation. However, for men who subsequently develop oligorecurrent disease, outcomes following second SBRT are unknown. Methods: A retrospective, single-center, cohort study was conducted. Pts were identified through electronic health records. Inclusion criteria included pts with oligometastatic (1-5 lesions) PCa detected on PSMA, fluciclovine, or choline C-11 PET who underwent 2 consecutive courses of SBRT to tracer-avid oligometastatic disease between 7/2013 and 7/2021. Exclusion criteria included presence of visceral metastases and pure small cell neuroendocrine PCa. Data on stage, tracer type, concurrent systemic therapy, and prostate-specific antigen (PSA) responses for first SBRT (SBRT1) and second SBRT (SBRT2) were collected. Outcomes included PSA decline of ≥50% (PSA50), ≥90% (PSA90), and PSA-PFS. SBRT2 outcomes were compared based on change of concurrent systemic therapy with SBRT2 (e.g., addition of abiraterone or anti-androgen withdrawal) and PSA50 to SBRT1 using Fisher’s exact text and Wilcoxon rank sum test, respectively. Results: A total of 12 pts met eligibility criteria. At SBRT1, 10 (83%) pts had hormone-sensitive PCa (HSPC) and 2 (17%) had castration-resistant PCa (CRPC). For PET tracers, 7 (58%) used PSMA, 4 (33%) fluciclovine, and 1 (8%) choline. After SBRT1, 12 pts (100%) had a PSA decline, 8 (67%) had a PSA50 response, and 6 (50%) a PSA90 response. Median PSA PFS after SBRT1 was 30mo (95%CI 9-65mo). Six (50%) SBRT1 pts had a concurrent change in systemic therapy. At SBRT2, 8 (67%) pts had HSPC and 4 (33%) had CRPC; 7 (58%) used PSMA and 5 (42%) fluciclovine. After SBRT2, 12 (100%) pts had a PSA decline, 8 (67%) had a PSA50 response, and 8 (67%) a PSA90 response. After SBRT2, median PSA PFS was 23mo (95%CI 12-35mo). Among 7 pts who had a concurrent change in systemic therapy with SBRT2, all (100%) had a PSA50 response; among 5 who did not (4 of whom did not receive any systemic therapy), 1 (20%) had a PSA50 response (P=0.01). Among 8 pts who had a PSA50 response to SBRT1, 7 (88%) had one to SBRT2; among 4 who did not have a PSA50 response to SBRT1, 1 (25%) had one to SBRT2 (P=0.01). No complications related to SBRT were documented. Conclusions: Serial SBRT for oligometastatic PCa detected on fluciclovine, PSMA, or choline PET is feasible and can achieve PSA declines independent of systemic therapy. PSA responses were greater when systemic therapy was changed. This preliminary evidence of benefit, based on PSA responses and PSA PFS, provides rationale for larger, prospective studies of serial SBRT for oligometastatic PCa.

Single-cell analysis of human primary prostate cancer reveals the heterogeneity of tumor-associated epithelial cell states

Prostate cancer is the second most common malignancy in men worldwide and consists of a mixture of tumor and non-tumor cell types. To characterize the prostate cancer tumor microenvironment, we perform single-cell RNA-sequencing on prostate biopsies, prostatectomy specimens, and patient-derived organoids from localized prostate cancer patients. We uncover heterogeneous cellular states in prostate epithelial cells marked by high androgen signaling states that are enriched in prostate cancer and identify a population of tumor-associated club cells that may be associated with prostate carcinogenesis. ERG-negative tumor cells, compared to ERG-positive cells, demonstrate shared heterogeneity with surrounding luminal epithelial cells and appear to give rise to common tumor microenvironment responses. Finally, we show that prostate epithelial organoids harbor tumor-associated epithelial cell states and are enriched with distinct cell types and states from their parent tissues. Our results provide diagnostically relevant insights and advance our understanding of the cellular states associated with prostate carcinogenesis.

Implementing Patient-Directed Cancer Education Materials Across Nigeria

As access to cancer care expands in low-income countries, developing tools to educate patients is paramount. We took a picture booklet, which was initially developed by the nonprofit Global Oncology for Malawi and Rwanda, and adapted it for use in Nigeria. The primary goal was to assess acceptability and provide education. The secondary goals were (1) to describe the collaboration, (2) to assess knowledge gained from the intervention, (3) to assess patient understanding of their therapy intent, and (4) to explore patient's experiences via qualitative analysis.

In this cross-continent collaboration supported by @StanfordCIGH, low literacy-friendly cancer education booklets developed by @GlobalOnc increased awareness and knowledge about cancer treatment in 4 diverse sites in Nigeria.

Integrated evaluation of telomerase activation and telomere maintenance across cancer cell lines

In cancer, telomere maintenance is critical for the development of replicative immortality. Using genome sequences from the Cancer Cell Line Encyclopedia and Genomics of Drug Sensitivity in Cancer Project, we calculated telomere content across 1299 cancer cell lines. We find that telomerase reverse transcriptase (TERT) expression correlates with telomere content in lung, central nervous system, and leukemia cell lines. Using CRISPR/Cas9 screening data, we show that lower telomeric content is associated with dependency of CST telomere maintenance genes. Increased dependencies of shelterin members are associated with wild-type TP53 status. Investigating the epigenetic regulation of TERT, we find widespread allele-specific expression in promoter-wildtype contexts. TERT promoter-mutant cell lines exhibit hypomethylation at PRC2-repressed regions, suggesting a cooperative global epigenetic state in the reactivation of telomerase. By incorporating telomere content with genomic features across comprehensively characterized cell lines, we provide further insights into the role of telomere regulation in cancer immortality.

IGFBP-3 and TGF-β inhibit growth in epithelial cells by stimulating type V TGF-β receptor (TβR-V)-mediated tumor suppressor signaling

The TGF-β type V receptor (TβR-V) mediates growth inhibition by IGFBP-3 and TGF-β in epithelial cells and loss of TβR-V expression in these cells leads to development of carcinoma. The mechanisms by which TβR-V mediates growth inhibition (tumor suppressor) signaling remain elusive. Previous studies revealed that IGFBP-3 and TGF-β inhibit growth in epithelial cells by stimulating TβR-V-mediated IRS-1/2-dependent activation and cytoplasm-to-nucleus translocation of IGFBP-3- or TGF-β-stimulated protein phosphatase (PPase), resulting in dephosphorylation of pRb-related proteins (p107, p130) or pRb, and growth arrest. To define the signaling, we characterized/identified the IGFBP-3- and TGF-β-stimulated PPases in cell lysates and nucleus fractions in Mv1Lu cells treated with IGFBP-3 and TGF-β, using a cell-free assay with 32P-labeled casein as a substrate. Both IGFBP-3- and TGF-β-stimulated PPase activities in cell lysates are abolished when cells are co-treated with TGF-β/IGFBP-3 antagonist or RAP (LRP-1/TβR-V antagonist). However, the IGFBP-3-stimulated PPase activity, but not TGF-β-stimulated PPase activity, is sensitive to inhibition by okadaic acid (OA). In addition, OA or PP2Ac siRNA reverses IGFBP-3 growth inhibition, but not TGF-β growth inhibition, in Mv1Lu and 32D cells. These suggest that IGFBP-3- and TGF-β-stimulated PPases are identical to PP2A and PP1, respectively. By Western blot/phosphorimager/immunofluorescence-microscopy analyses, IGFBP-3 and TGF-β stimulate TβR-V-mediated IRS-2-dependent activation and cytoplasm-to-nucleus translocation of PP2Ac and PP1c, resulting in dephosphorylation of p130/p107 and pRb, respectively, and growth arrest. Small molecule TGF-β enhancers, which potentiate TGF-β growth inhibition by enhancing TβR-I-TβR-II-mediated canonical signaling and thus activating TβR-V-mediated tumor suppressor signaling cascade (TβR-V/IRS-2/PP1/pRb), could be used to prevent and treat carcinoma.

How Cancer Risk SNPs May Contribute to Prostate Cancer Disparities

Disparities in cancer incidence, prevalence, burden, and outcome exist among specific population groups in the United States. Researchers have identified germline genetic risk single-nucleotide polymorphisms (SNP) that differ by ancestry and may contribute to some of these differences. In this issue of Cancer Research, Han and colleagues found the prostate cancer risk SNP rs4713266 is associated with increased risk of patients with African ancestry. The authors investigated the functional role of the risk SNP, finding that it alters activity of a NEDD9 enhancer and increases NEDD9 expression. The study provides epidemiologic and mechanistic insight into factors that may drive prostate cancer disparities.See related article by Han et al., p. 3766.

Rate of skeletal-related events (SREs) for abiraterone acetate (AA) versus enzalutamide (ENZ) in prostate cancer: A population-based study using the SEER-Medicare database

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Background: Skeletal-related events are common in men with prostate cancer, and are associated with significant morbidity and mortality. AA and ENZ are novel androgen signaling inhibitors used in the treatment of metastatic prostate castration-resistant prostate cancer (mCRPC). As directly comparative efficacy data do not exist between AA and ENZ, the differing toxicity profiles inform treatment selection. It is unknown whether SRE rates differ in a real-world population between AA, which is given with corticosteroids, and ENZ, which is associated with imbalance and falls. Methods: The national SEER-Medicare linked database was used to identify men with prostate cancer who received AA or ENZ between 2011-2015; approval during this period was solely for mCRPC. Inclusion criteria included Medicare Part A+B coverage 1 year before and after first receipt of AA/ENZ, without any HMO enrollment. Baseline demographic and comorbidity data were gathered. Diagnosis and procedure claims codes were used to identify SREs, defined as pathologic fracture, surgery to bone, radiation to bone, or spinal cord compression. The time to SRE was defined as time from first receipt of AA/ENZ to the first SRE of any type. A multivariable competing risk regression analysis including death as a competing risk was performed. Results: 5,856 men with prostate cancer who first received AA (N = 4,207) or ENZ (N = 1,649) were identified. The median age at initiation of AA/ENZ was 70 years (range 65-101); 78% were White, 12% Black, 4% Hispanic, 3% Asian, and 4% Other. The median follow-up was 14 months. The overall SRE rate was 13.1% after AA/ENZ start: 574 (13.6%) AA and 194 (11.8%) ENZ, with a cumulative incidence of 11.9% at 2 years. Median overall survival was 16 months (14.4 months for AA and 18.3 months for ENZ). Age, stage at diagnosis, race/ethnicity, baseline comorbidities, and prior history of SRE were balanced between AA vs ENZ, aside from baseline osteoarthritis or rheumatoid arthritis (48.0% AA vs 53.2% ENZ, P < 0.001) and baseline Alzheimer’s dementia (9.2% AA vs 11.1% ENZ, P = 0.03). After controlling for these potential risk factors, receipt of AA versus ENZ was not associated with time to SRE (relative risk ratio [RR] = 0.90, 95% CI 0.77-1.06, P = 0.22). Osteoporosis (RR 1.22, 95% CI 1.01-1.49, P = 0.04), osteoarthritis or rheumatoid arthritis (RR 1.23, 95% CI 1.06-1.43, P < 0.01), and prior history of SRE (RR 1.31, 95% CI 1.07-1.59, P < 0.01) were statistically significant risk factors for SRE. Conclusions: In this real-world population of men with prostate cancer, there was no difference in time to SRE between AA and ENZ. Clinical decision-making on whether to prescribe AA or ENZ should be informed by other potential toxicities as well as cross-resistance with sequencing of these therapies. Analysis of impact of bone protective agent use is underway.

TERT promoter mutations and other prognostic factors in patients with advanced urothelial carcinoma treated with an immune checkpoint inhibitor

BACKGROUND

Immune checkpoint inhibitors (ICI) can achieve durable responses in a subset of patients with locally advanced or metastatic urothelial carcinoma (aUC). The use of tumor genomic profiling in clinical practice may help suggest biomarkers to identify patients most likely to benefit from ICI.

METHODS

We undertook a retrospective analysis of patients treated with an ICI for aUC at a large academic medical center. Patient clinical and histopathological variables were collected. Responses to treatment were assessed for all patients with at least one post-baseline scan or clear evidence of clinical progression following treatment start. Genomic profiling information was also collected for patients when available. Associations between patient clinical/genomic characteristics and objective response were assessed by logistic regression; associations between the characteristics and progression-free survival (PFS) and overall survival (OS) were examined by Cox regression. Multivariable analyses were performed to identify independent prognostic factors.

RESULTS

We identified 119 aUC patients treated with an ICI from December 2014 to January 2020. Genomic profiling was available for 78 patients. Overall response rate to ICI was 29%, and median OS (mOS) was 13.4 months. Favorable performance status at the start of therapy was associated with improved OS (HR 0.46, p=0.025) after accounting for other covariates. Similarly, the presence of a TERT promoter mutation was an independent predictor of improved PFS (HR 0.38, p=0.012) and OS (HR 0.32, p=0.037) among patients who had genomic profiling available. Patients with both a favorable performance status and a TERT promoter mutation had a particularly good prognosis with mOS of 21.1 months as compared with 7.5 months in all other patients (p=0.03).

CONCLUSIONS

The presence of a TERT promoter mutation was an independent predictor of improved OS in a cohort of aUC patients treated with an ICI who had genomic data available. Most of the clinical and laboratory variables previously shown to be prognostic in aUC patients treated with chemotherapy did not have prognostic value among patients treated with an ICI. Genomic profiling may provide important prognostic information and affect clinical decision making in this patient population. Validation of these findings in prospective patient cohorts is needed.

Evaluating the transcriptional fidelity of cancer models

BACKGROUND

Cancer researchers use cell lines, patient-derived xenografts, engineered mice, and tumoroids as models to investigate tumor biology and to identify therapies. The generalizability and power of a model derive from the fidelity with which it represents the tumor type under investigation; however, the extent to which this is true is often unclear. The preponderance of models and the ability to readily generate new ones has created a demand for tools that can measure the extent and ways in which cancer models resemble or diverge from native tumors.

METHODS

We developed a machine learning-based computational tool, CancerCellNet, that measures the similarity of cancer models to 22 naturally occurring tumor types and 36 subtypes, in a platform and species agnostic manner. We applied this tool to 657 cancer cell lines, 415 patient-derived xenografts, 26 distinct genetically engineered mouse models, and 131 tumoroids. We validated CancerCellNet by application to independent data, and we tested several predictions with immunofluorescence.

RESULTS

We have documented the cancer models with the greatest transcriptional fidelity to natural tumors, we have identified cancers underserved by adequate models, and we have found models with annotations that do not match their classification. By comparing models across modalities, we report that, on average, genetically engineered mice and tumoroids have higher transcriptional fidelity than patient-derived xenografts and cell lines in four out of five tumor types. However, several patient-derived xenografts and tumoroids have classification scores that are on par with native tumors, highlighting both their potential as faithful model classes and their heterogeneity.

CONCLUSIONS

CancerCellNet enables the rapid assessment of transcriptional fidelity of tumor models. We have made CancerCellNet available as a freely downloadable R package ( https://github.com/pcahan1/cancerCellNet ) and as a web application ( http://www.cahanlab.org/resources/cancerCellNet_web ) that can be applied to new cancer models that allows for direct comparison to the cancer models evaluated here.

Tackling Diversity in Prostate Cancer Clinical Trials: A Report From the Diversity Working Group of the IRONMAN Registry

Prostate cancer disproportionately affects racial and ethnic minority populations. Reasons for disparate outcomes among minority patients are multifaceted and complex, involving factors at the patient, provider, and system levels. Although advancements in our understanding of disease biology have led to novel therapeutics for men with advanced prostate cancer, including the introduction of biomarker-driven therapeutics, pivotal translational studies and clinical trials are underrepresented by minority populations. Despite attempts to bridge the disparities gap, there remains an unmet need to expand minority engagement and participation in clinical trials to better define the impact of therapy on efficacy outcomes, quality of life, and role of biomarkers in diverse patient populations. The IRONMAN registry (ClinicalTrials.gov identifier: NCT03151629), a global, prospective, population-based study, was borne from this unmet medical need to address persistent gaps in our knowledge of advanced prostate cancer. Through integrated collection of clinical outcomes, patient-reported outcomes, epidemiologic data, and biospecimens, IRONMAN has the goal of expanding our understanding of how and why prostate cancer outcomes differ by race and ethnicity. To this end, the Diversity Working Group of the IRONMAN registry has developed informed strategies for site selection, recruitment, engagement and retention, and trial design and eligibility criteria to ensure broad inclusion and needs awareness of minority participants. In concert with systematic strategies to tackle the complex levels of disparate care, our ultimate goal is to expand minority engagement in clinical research and bridge the disparities gap in prostate cancer care.

Implementation of clinician-facing prostate cancer therapeutic clinical trial decision tool at a comprehensive cancer center

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Background: The conventional model for clinical trial (CT) recruitment relies on clinicians to identify potential CTs for patients. Internet technology can be leveraged as a decision tool to enhance the CT recruitment process. Methods: An internet-based, clinician-facing decision tool was developed in genitourinary medical oncology clinic at a Comprehensive Cancer Center (CCC). The tool provided access to a real-time, tailored list of treatment CTs actively recruiting patients with PCa at the CCC based on clinical characteristics inputted by user. The clinical data was summarized. All clinicians (n = 9) with access to the decision tool completed a survey to assess effectiveness and satisfaction. Results: During a 9-month pilot period, user engagement increased from a baseline of 36 to 136 cases per month, with a total of 644 cases overall. Among cases, 525 had metastatic disease, 436 of which were metastatic castration resistant PCa (mCRPC). Overall, 145 cases were classified as having oligo-metastatic ( < = 3) PCa, 93 of whom were also mCRPC. Prior treatments received included abiraterone in hormone-sensitive PCa (HSPC 19.3%, CRPC 48.7%); enzalutamide (HSPC 3.7%, CRPC 34.9%) apalutamide (HSPC 1.3%, CRPC 6.9%), taxane (HSPC 17.2%, CRPC 27.8%), radium-223 (6.1%), sipuleucel-T (18.3%), parp inhibitors (4%), or check-point inhibitors (6%). Clinician-inputted genomics of cases included CDK12 (20.9%), MSI-high disease (13.6%), BRCA1/2 (32.7%), ARID1a (7.3%), ATM (21.8%), FANCA (4.5%), or CHEK2 (6.4%) and HDAC2 (0.9%). Among survey respondents, use of tool in clinic was reported sometimes (22%), often/always (78%). Results of decision tool were reported to inform treatment sometimes (22%) or often/always (78%). Respondents confidence in often/always knowing all available CTs increased from a baseline of 0% to 89%, and 89% of users reported very/complete satisfaction with decision tool. Conclusions: An internet-based CT decision tool for provides detailed clinical characteristics of patients for whom CTs are being considered at a CCC. Clinicians using the decision tool report high levels of satisfaction. The tool was effective in increasing confidence in knowledge of current available CTs. Data gathered in the decision tool may inform future CT development. Future research with expanded use of decision tool among referring clinicians will assess its impact in promoting diversity among CT participants.

The role of androgen deprivation therapy on the clinical course of COVID-19 infection in men with prostate cancer

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Background: TMPRSS2, a cell surface protease which is commonly upregulated in prostate cancer (PC) and regulated by androgens, is a necessary component for SARS-CoV2 cellular entry into respiratory epithelial cells. PC patients receiving ADT were reported to have a lower risk of SARS-CoV-2 infection. However, whether ADT may have an impact on the severity of COVID-19 illness in this population is poorly understood. Methods: In this study performed across 7 US medical centers, we retrospectively evaluated patients with active PC and SARS-COV-2 viral detection by PCR between 03/01/20 and 05/31/20. We collected information on demographics; medical comorbidities; medications; PC Gleason score at initial diagnosis; presence of active disease, metastases, and castration resistance; ADT use as defined by GnRH analog or antagonist within 3 months or castration levels of testosterone < 50 ng/dL within 6 months of COVID-19 diagnosis, or history of bilateral orchiectomy; active non-ADT systemic therapies including, but not limited to, androgen-receptor-targeted therapies and chemotherapy; and COVID-19-related outcomes including hospitalization, supplemental oxygen use, mechanical ventilation requirement, WHO COVID-19 ordinal scale for clinical improvement, follow-up duration, and vital status. Multivariable mixed-effect logistic regression was performed to evaluate any difference in COVID-19 clinical outcomes between patients on and not on ADT. Survival analysis was done using adjusted Cox proportion-hazards regression model. All tests were two-sided at 0.05 significance level. Results: We identified 465 evaluable patients with median age of 71 (61-81) years. Median duration of follow-up was 60 (12-114.2) days. In this follow up period, there were 195 (41.9%) hospitalizations and 111 (23.9%) deaths. When adjusted for age, BMI, and PC clinical disease state, overall survival (HR 1.28 [95%CI 0.79-2.08], P = 0.32), hospitalization status (HR 1.07 [0.61-1.87], P = 0.82), supplemental oxygen use (HR 1.29 [0.77-2.17], P = 0.34), and use of mechanical ventilation (HR 1.07 [0.51-2.23], P = 0.87) were not statistically different between ADT and non-ADT cohorts. Similarly, in subgroup analysis, no statistical difference in overall survival was found between ADT and non-ADT cohorts for hospitalized patients (HR 1.42 [0.82-2.47], P = 0.21) and those receiving supplemental oxygen (HR 1.10 [0.65-1.85], P = 0.73). Conclusions: In this retrospective cohort of PC patients, use of ADT prior to COVID-19 diagnosis does not protect against severe COVID-19 illness as defined by hospitalization, supplemental oxygen use, or death. Further preclinical work in understanding TMPRSS2 expression and androgen regulation in respiratory epithelial cells is needed. As well, longer clinical follow-up and additional clinical studies inclusive of prospective data are warranted to fully address this question.

Single-cell analysis of cellular state heterogeneity in human localized prostate cancer

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Background: Prostate cancer is the second most common malignancy in men worldwide. The development of cancer from prostate tissue involves complex interactions of tumor cells with surrounding epithelial and stromal cells and can occur multifocally, suggesting that prostate epithelial cells may undergo cellular state transitions towards carcinogenesis. Previous studies on localized prostate cancer molecular changes have focused on unsorted bulk tissue samples, leaving a gap in our understanding of the cellular heterogeneity in the tumor microenvironment. Single-cell analyses of tumor specimens have the potential to reveal, at unprecedented resolution, cellular composition, as well as instructive intercellular interactions. Methods: To characterize the localized prostate cancer tumor microenvironment, we performed single-cell RNA-sequencing (scRNA-seq) on prostate biopsies, radical prostatectomy specimens, and matched patient-derived organoids from localized prostate cancer patients. Results: Within prostate epithelial cells, we identified a population of club cells that may act as progenitor cells. Furthermore, we uncovered luminal-like epithelial cellular states augmented in androgen signaling across basal and club cell populations. By classifying tumor cells based on ERG expression status, we found that ERG- tumor cells, in contrast to ERG+ cells, share transcriptomic heterogeneity with surrounding luminal epithelial cells and are associated with common stromal and immune microenvironment responses. These results suggest that specific immune niches may arise based on TMPRSS2-ERG fusion status. Finally, we generated prostate epithelial organoids derived from matched localized prostate cancer patients and characterized their transcriptomic profiles by scRNA-seq. These patient-derived organoids recapitulated tumor-associated epithelial cell states but also harbored distinct cell types and states from their parent tissues. Conclusions: Our data from localized prostate cancer specimens and organoids provide diagnostically relevant insights and will help advance our understanding of the cancer cellular states associated with prostate carcinogenesis.

Androgen deprivation therapy and risk of SARS-CoV-2 infection in men with prostate cancer: A University of California (UC) Health System registry study

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Background: SARS-CoV-2 entry into host cells is facilitated by the transmembrane protease TMPRSS2. TMPRSS2 expression can be modulated by the androgen receptor. It is unclear whether androgen deprivation therapy (ADT) may partially protect from SARS-CoV-2 infection. Methods: A retrospective registry study of adult men with prostate cancer who underwent testing for SARS-CoV-2 in the UC Health System between February 1, 2020 and October 6, 2020 was performed. The University of California Health COVID Research Data Set (UC CORDS), which includes electronic health data of all patients who underwent testing for SARS-CoV-2 at 5 UC academic medical centers (UC Davis, UC Irvine, UC Los Angeles, UC San Diego, and UC San Francisco) and 12 affiliated hospitals across California, was used. Association of SARS-CoV-2 infection and receipt of ADT (GnRH agonist or antagonist) within 90 days of COVID testing was determined using the Chi-Squared test. Analyses (Chi-Squared or Fisher’s exact tests) were also performed in race/ethnicity subgroups. Results: Overall, 2,948 men with prostate cancer who underwent SARS-CoV-2 testing were identified, of whom 59 (2.0%) tested positive. Of the 2,948 men, 2,124 (72%) were White; 219 (7%) Black or African-American; 182 (6%) Asian or Native Hawaiian/Pacific-Islander; 176 (6%) Other race; and 247 (8%) Unknown race. There were 235 (8%) Hispanic or Latino men. Among the 444 men who received ADT in the entire cohort, 7 (1.6%) tested positive, and among the 2,504 men who did not receive ADT, 52 (2.1%) tested positive (OR 0.76, 95% CI 0.34-1.67, P = 0.49). No statistically significant association between ADT and SARS-CoV-2 positivity was found within race or ethnicity subgroups. Conclusions: No association between the use of ADT and the risk of testing positive for SARS-CoV-2 was identified in this study of a diverse patient population in the University of California Health System medical centers and hospitals. In this setting of an overall low prevalence of SARS-CoV-2 infection, thus far, there is no strong evidence of a protective benefit of ADT.

TERT promoter mutation as a prognostic marker in patients with advanced urothelial carcinoma treated with immune checkpoint inhibitors

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Background: Reliable predictive markers are lacking in patients (pts) with locally advanced or metastatic urothelial carcinoma (aUC) treated with immune checkpoint inhibitors (ICI). We sought to determine whether specific genomic alterations could be used to predict overall survival (OS) in this patient population. Methods: We undertook a retrospective cohort study of pts with aUC who received ICI and underwent genomic profiling by next-generation sequencing (NGS). All patients underwent NGS using commercially available platforms (e.g. Foundation Medicine, Strata, Invitae), or testing on the CLIA-certified institutional panel UCSF500. Associations between the 20 most frequently altered genes and OS were first examined by Cox regression. Genes with a p <0.1 on univariate analysis and relevant clinical variables were then included in a multivariable analysis. Results: We identified 78 pts treated with ICI for aUC with available genomic profiling results. Median age at ICI initiation was 71; the majority of patients had visceral metastases (70.5%), ECOG performance status ≤1 (62.8%) and received ICI in the post-platinum setting (52.6%). Objective response rate in this cohort was 35.9%, median progression free survival was 4.0 months (95% CI 2.6-10.5) and median OS was 17.5 months (95% CI 14.1-NR) from ICI start. The most commonly altered genes were the TERT promoter (TERTp) (61%), TP53 (52%), RB1 (31%), CDKN2A(29%) and CDKN2B (27%). On univariable analysis there was a trend towards longer OS in pts with TERTp mutations (HR 0.53, 95% CI 0.27-1.06, p = 0.07), and shorter OS in pts with CDKN2B mutations (HR 1.91, 95% CI 0.98-3.73, p = 0.06). Both mutations were included in a multivariable analysis. After adjusting for known prognostic variables (ECOG PS, visceral metastases, albumin, hemoglobin, body mass index [BMI], neutrophil to lymphocyte ratio [NLR], and histology), the presence of a TERTp mutation was significantly associated with improved OS (HR 0.30, 95% CI 0.10-0.93, p = 0.04; Table). Conclusions: The presence of a TERTp mutation was an independent predictor of improved OS in a cohort of aUC pts treated with ICI. Other common mutations and clinical variables were not associated with OS on a multivariable analysis. These findings are hypothesis-generating and prospective validation is needed. [Table: see text]

The DNA methylation landscape of advanced prostate cancer

Although DNA methylation is a key regulator of gene expression, the comprehensive methylation landscape of metastatic cancer has never been defined. Through whole-genome bisulfite sequencing paired with deep whole-genome and transcriptome sequencing of 100 castration-resistant prostate metastases, we discovered alterations affecting driver genes only detectable with integrated whole-genome approaches. Notably, we observed that 22% of tumors exhibited a novel epigenomic subtype associated with hyper-methylation and somatic mutations in TET2, DNMT3B, IDH1, and BRAF. We also identified intergenic regions where methylation is associated with RNA expression of the oncogenic driver genes AR, MYC and ERG. Finally, we showed that differential methylation during progression preferentially occurs at somatic mutational hotspots and putative regulatory regions. This study is a large integrated study of whole-genome, whole-methylome and whole-transcriptome sequencing in metastatic cancer and provides a comprehensive overview of the important regulatory role of methylation in metastatic castration-resistant prostate cancer.

Genomic Profiling of Prostate Cancers from Men with African and European Ancestry

PURPOSE

African American (AFR) men have the highest mortality rate from prostate cancer (PCa) compared with men of other racial/ancestral groups. Differences in the spectrum of somatic genome alterations in tumors between AFR men and other populations have not been well-characterized due to a lack of inclusion of significant numbers in genomic studies.

EXPERIMENTAL DESIGN

To identify genomic alterations associated with race, we compared the frequencies of somatic alterations in PCa obtained from four publicly available datasets comprising 250 AFR and 611 European American (EUR) men and a targeted sequencing dataset from a commercial platform of 436 AFR and 3018 EUR men.

RESULTS

Mutations in ZFHX3 as well as focal deletions in ETV3 were more frequent in tumors from AFR men. TP53 mutations were associated with increasing Gleason score. MYC amplifications were more frequent in tumors from AFR men with metastatic PCa, whereas deletions in PTEN and rearrangements in TMPRSS2-ERG were less frequent in tumors from AFR men. KMT2D truncations and CCND1 amplifications were more frequent in primary PCa from AFR men. Genomic features that could impact clinical decision making were not significantly different between the two groups including tumor mutation burden, MSI status, and genomic alterations in select DNA repair genes, CDK12, and in AR.

CONCLUSIONS

Although we identified some novel differences in AFR men compared with other populations, the frequencies of genomic alterations in current therapeutic targets for PCa were similar between AFR and EUR men, suggesting that existing precision medicine approaches could be equally beneficial if applied equitably.

Diversity of Enrollment in Prostate Cancer Clinical Trials: Current Status and Future Directions

BACKGROUND

Although there are considerable racial and ethnic disparities in prostate cancer incidence and mortality in the United States and globally, clinical trials often do not reflect disease incidence across racial and ethnic subgroups. This study aims to comprehensively review the reporting of race and ethnicity data and the representation of race and ethnicity across prostate cancer treatment-, prevention-, and screening-based clinical trials.

METHODS

Seventy-two global phase III and IV prevention, screening, and treatment prostate cancer clinical trials with enrollment start dates between 1987 and 2016 were analyzed in this study, representing a total of 893,378 individual trial participants. Availability and representation of race and ethnicity data by trial funding type, temporal changes in the racial/ethnic diversity of participants, and geographic representation of countries were assessed.

RESULTS

Of the 72 trials analyzed, 59 (81.9%) had available race data, and 11 (15.3%) of these trials additionally reported ethnicity. Of the trials reporting data, participants were overwhelmingly white men (with the highest proportion in U.S. nonpublicly funded trials), comprising over 96% of the study population. The proportion of white participants in prostate cancer clinical trials has remained at over 80% since 1990. Geographically, Africa and the Caribbean were particularly underrepresented with only 3% of countries included.

CONCLUSIONS

Trial participants continue to be majority white despite the known racial disparities in prostate cancer clinical outcomes.

IMPACT

Current and future trials must use novel recruitment strategies to ensure enrollment of underrepresented men. Targeting the inclusion of African and Caribbean medical centers is crucial to achieve equity in representation.

Mesenchymal and MAPK Expression Signatures Associate with Telomerase Promoter Mutations in Multiple Cancers

In a substantial fraction of cancers TERT promoter (TERTp) mutations drive expression of the catalytic subunit of telomerase, contributing to their proliferative immortality. We conducted a pan-cancer analysis of cell lines and find a TERTp mutation expression signature dominated by epithelial-to-mesenchymal transition and MAPK signaling. These data indicate that TERTp mutants are likely to generate distinctive tumor microenvironments and intercellular interactions. Analysis of high-throughput screening tests of 546 small molecules on cell line growth indicated that TERTp mutants displayed heightened sensitivity to specific drugs, including RAS pathway inhibitors, and we found that inhibition of MEK1 and 2, key RAS/MAPK pathway effectors, inhibited TERT mRNA expression. Consistent with an enrichment of mesenchymal states in TERTp mutants, cell lines and some patient tumors displayed low expression of the central adherens junction protein E-cadherin, and we provide evidence that its expression in these cells is regulated by MEK1/2. Several mesenchymal transcription factors displayed elevated expression in TERTp mutants including ZEB1 and 2, TWIST1 and 2, and SNAI1. Of note, the developmental transcription factor SNAI2/SLUG was conspicuously elevated in a significant majority of TERTp-mutant cell lines, and knock-down experiments suggest that it promotes TERT expression. IMPLICATIONS: Cancers harboring TERT promoter mutations are often more lethal, but the basis for this higher mortality remains unknown. Our study identifies that TERTp mutants, as a class, associate with a distinct gene and protein expression signature likely to impact their biological and clinical behavior and provide new directions for investigating treatment approaches for these cancers.

Combined 18F-naf and fluciclovine administration for PET imaging of prostate cancer

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Background: 18F-fluciclovine is FDA approved for the detection of recurrent and metastatic prostate cancer. At our institution, 18F-fluciclovine PET had replaced 18F-NaF PET, but fluciclovine has mild to no uptake in dense sclerotic bony lesions. F18-NaF offers increased sensitivity and specificity in detection of osseous metastases and therefore we converted to using a combination of 18F-NaF and 18F-fluciclovine in patients with biochemical recurrence. In this study, we assessed the feasibility of performing a combined F18- fluciclovine and F18-NaF study, and evaluated the biodistribution of the combined radiotracers in patients with prostate cancer. Methods: We retrospectively reviewed 16 consecutive patients over a period of 3 months. 5 mCi of F18-NaF was injected, followed 45 minutes later by a 10 mCi injection of F18-fluciclovine. Patients were asked to hydrate after NaF injection and empty their bladder immediately prior to scanning. A non-diagnostic CT for attenuation correction and an emission PET scan were acquired on a time of flight Discovery 690 PET/CT (GE Healthcare) within 5 minutes of fluciclovine injection. We characterized the extent of soft tissue and osseous disease, as well as assessed the image quality, taking note for F18-NaF excretion in the bladder and the potential scatter artifact limiting evaluation of the prostate bed. Results: On average patients received 5.5 +/- 0.5 mCi of F18-NaF and 10.4 +/- 0.8 mCi of F18-fluciclovine. All 16 patients had diagnostic quality scans. None had limited evaluation of the prostate bed secondary to artifacts from bladder scatter. 10 patients (62.5%) had residual or recurrent prostate cancer within the prostate bed, of which 3 (18.8%) had distant nodal disease in the perirectal, pelvis, retroperitoneal, or periaortic lymph node regions. 7 patients (43.8%) demonstrated osseous metastatic lesions within the clavicle, sternum, iliac wing, vertebra, coccyx, or sacrum. Conclusions: Combined 18F-NaF and 18F-fluciclovine scans in patients with prostate cancer is a feasible method for detecting soft tissue recurrence and osseous disease. Bladder excretion from F18-NaF does not obscure the prostate bed nor degrades the diagnostic quality of the exam. The combined use of 18F-fluciclovine and F18-NaF in one PET/CT acquisition has the potential to increase the sensitivity for detecting prostate cancer and limit the time and radiation dose delivered compared to the conventional, separate acquisitions of the two radiotracers.

Cancer in Belize: Characteristics of patients presenting to a public oncology clinic

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Background: Belize is a middle-income country in Central America with significant inequality. To date, data on the oncologic burden of disease has been imputed from mortality data. The first-ever public oncology program was started in 2018, which allowed us to analyze the presenting characteristics of patients with cancer. Methods: 284 patients were seen at the Karl Heusner Memorial Hospital (KHMH) oncology clinic between April 2018 and July 2019. We performed a retrospective chart review and extracted patient characteristics to understand the burden of cancer in Belize. Results: Of 284 patients seen, 63% had a confirmed pathologic diagnosis of cancer and the remaining were clinically suspected to have cancer. 56% were female and the median age was 55. Breast, cervix, colon, and prostate were the most common types of cancer seen. Breast and cervical cancers disproportionately affected young women with a median age at presentation of 51 and 45 respectively. 28% of patients presented with Stage IV disease. 43% of patients were deemed candidates only for comfort care. Conclusions: The burden of oncologic disease in Belize is significant and represents a wide variety of cancers. Breast and cervical cancers disproportionately affect young women in Belize. A significant proportion of patients presented with late stage disease, likely due to the lack of screening programs and cancer awareness in the country. Addressing the country’s cancer burden will require strengthening local pathology and surgical oncology capabilities, establishing a public chemotherapy treatment program, and referring patients to radiation oncology in nearby countries.

Assessing and Addressing the Need for Cancer Patient Education in a Resource-Limited Setting in Haiti

PURPOSE

Misinformation and lack of information about cancer and its treatment pose significant challenges to delivering cancer care in resource-limited settings and may undermine patient engagement in care. We aimed to investigate patients' knowledge and attitudes toward cancer and its treatment and to adapt, implement, and evaluate a low-literacy cancer patient education booklet at the Hôpital Universitaire de Mirebalais (HUM) in rural Haiti.

MATERIALS AND METHODS

A low-literacy cancer patient education booklet was adapted into Haitian Creole in collaboration with clinicians at HUM. Patients were recruited for structured interviews (n = 20) and two focus groups (n = 13) designed to explore patients' attitudes toward cancer and its treatment and to assess whether the booklet increased patients' knowledge via an investigator-designed knowledge test.

RESULTS

Participants reported a subjective lack of knowledge about cancer and its treatments and described views of cancer as deadly or incurable. Patients of varying education levels valued receiving written materials that set expectations about cancer treatment and expressed a desire to share the booklet with caregivers and others in their community. Participants across all levels of education significantly increased their performance on a knowledge test after counseling using the booklet (p < .001).

CONCLUSION

We found that an educational booklet about cancer developed in collaboration with local providers was well received by patients with variable literacy levels and improved their knowledge of cancer and its treatment in a resource-limited setting. Such educational materials have the potential to serve as tools to engage patients with cancer and their families in care.

IMPLICATIONS FOR PRACTICE

Misinformation and lack of information pose significant challenges to delivering cancer care in resource-limited settings; however, there are often no culturally and literacy appropriate tools available to aid in patient education. This article shows that written educational materials are well received by patients of variable literacy levels and can be effective tools for increasing patients' knowledge of cancer and its treatment in a limited-resource setting. Furthermore, the authors have made their educational booklet, Cancer and You, freely available online and welcome the opportunity to connect with readers of The Oncologist interested in implementing this educational booklet in clinical care.

Expression of ACE2, the SARS-CoV-2 receptor, and TMPRSS2 in prostate epithelial cells

The COVID-19 pandemic has spread across more than 200 countries and resulted in over 170,000 deaths. For unclear reasons, higher mortality rates from COVID-19 have been reported in men compared to women. While the SARS-CoV-2 receptor ACE2 and serine protease TMPRSS2 have been detected in lung and other tissues, it is not clear what sex differences may exist. We analyzed a publicly-available normal human prostate single-cell RNA sequencing dataset and found TMPRSS2 and ACE2 co-expressing cells in epithelial cells, with a higher proportion in club and hillock cells. Then we investigated datasets of lung epithelial cells and also found club cells co-expressing TMPRSS2 and ACE2. A comparison of ACE2 expression in lung tissue between males and females showed higher expression in males and a larger proportion of ACE2+ cells in male type II pneumocytes, with preliminary evidence that type II pneumocytes of all lung epithelial cell types showed the highest expression of ACE2. These results raise the possibility that sex differences in ACE2 expression and the presence of double-positive cells in the prostate may contribute to the observed disparities of COVID-19.

Treatment outcomes in metastatic prostate cancer patients with DNA damage repair mutations

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Background: DNA damage repair mutations (DDM) are common in prostate cancer (PCa). Optimal treatment sequence and outcomes of androgen signaling inhibitors (ASIs) and chemotherapy in this population are unclear. Methods: A retrospective, single-institution study of patients (pts) with mPCa and DDM detected on next-generation sequencing between January 2016 and July 2019 was conducted. For pts with metastatic castration-resistant prostate cancer (mCRPC), chi-squared and Wilcoxon sum rank tests were used to compare PSA50 and Time to Next Treatment (TNT) among different treatment groups, respectively. Results: Among 70 pts with mPCa and DDM, the most common mutations were BRCA2 (24, 27%), ATM (20, 22%), CDK12 (19, 21%), and MLH1/MSH2/MSH6/PMS2 (10, 11%). Fifty-seven pts (81%) received systemic treatment for mCRPC and 68% received ≥3 mCRPC treatments. Among 57 pts with ≥1 mCRPC treatment, 19 (33%) received first abiraterone, and 18 (32%) first enzalutamide. There was a trend toward higher PSA50 (74% vs 47%, P=0.196) and longer TNT (55 vs 34 wk, P=0.286) with first abiraterone vs enzalutamide. Upon switching between ASIs, 0 of 10 pts had a PSA50 response. When given chemotherapy at any point during CRPC treatment, 16/27 (59%) pts had a PSA50 response to docetaxel alone and/or cabazitaxel alone, and 14/24 (58%) to carboplatin-based regimens. Conclusions: To our knowledge, this is the largest single-institution cohort providing real-world treatment data for pts with mPCa and DDM. In the frontline mCRPC setting, abiraterone had a trend suggesting increased activity over enzalutamide that was not statistically significant. Switching ASIs at progression produced no additional responses, suggesting cross-resistance. Responses to taxanes were similar to previously reported data in all-comers. Validation in a larger, prospective cohort is needed to confirm these preliminary findings.