Assessing the Clinical Utility of Published Prostate Cancer Polygenic Risk Scores in a Large Biobank Data Set

BACKGROUND AND OBJECTIVE

Polygenic risk scores (PRSs) have been developed to identify men with the highest risk of prostate cancer. Our aim was to compare the performance of 16 PRSs in identifying men at risk of developing prostate cancer and then to evaluate the performance of the top-performing PRSs in differentiating individuals at risk of aggressive prostate cancer.

METHODS

For this case-control study we downloaded 16 published PRSs from the Polygenic Score Catalog on May 28, 2021 and applied them to Michigan Genomics Initiative (MGI) patients. Cases were matched to the Michigan Urological Surgery Improvement Collaborative (MUSIC) registry to obtain granular clinical and pathological data. MGI prospectively enrolls patients undergoing surgery at the University of Michigan, and MUSIC is a multi-institutional registry that prospectively tracks demographic, treatment, and clinical variables. The predictive performance of each PRS was evaluated using the area under the covariate-adjusted receiver operating characteristic curve (aAUC), and the association between PRS and disease aggressiveness according to prostate biopsy data was measured using logistic regression.

KEY FINDINGS AND LIMITATIONS

We included 18 050 patients in the analysis, of whom 15 310 were control subjects and 2740 were prostate cancer cases. The median age was 66.1 yr (interquartile range 59.9-71.6) for cases and 56.6 yr (interquartile range 42.6-66.7) for control subjects. The PRS performance in predicting the risk of developing prostate cancer according to aAUC ranged from 0.51 (95% confidence interval 0.51-0.53) to 0.67 (95% confidence interval 0.66-0.68). By contrast, there was no association between PRS and disease aggressiveness.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Prostate cancer PRSs have modest real-world performance in identifying patients at higher risk of developing prostate cancer; however, they are limited in distinguishing patients with indolent versus aggressive disease.

PATIENT SUMMARY

Risk scores using data for multiple genes (called polygenic risk scores) can identify men at higher risk of developing prostate cancer. However, these scores need to be refined to be able to identify men with the highest risk for clinically significant prostate cancer.

imply: improving cell-type deconvolution accuracy using personalized reference profiles

Using computational tools, bulk transcriptomics can be deconvoluted to estimate the abundance of constituent cell types. However, existing deconvolution methods are conditioned on the assumption that the whole study population is served by a single reference panel, ignoring person-to-person heterogeneity. Here, we present imply, a novel algorithm to deconvolute cell type proportions using personalized reference panels. Simulation studies demonstrate reduced bias compared with existing methods. Real data analyses on longitudinal consortia show disparities in cell type proportions are associated with several disease phenotypes in Type 1 diabetes and Parkinson's disease. imply is available through the R/Bioconductor package ISLET at https://bioconductor.org/packages/ISLET/ .

Fine-mapping analysis including over 254,000 East Asian and European descendants identifies 136 putative colorectal cancer susceptibility genes

Genome-wide association studies (GWAS) have identified more than 200 common genetic variants independently associated with colorectal cancer (CRC) risk, but the causal variants and target genes are mostly unknown. We sought to fine-map all known CRC risk loci using GWAS data from 100,204 cases and 154,587 controls of East Asian and European ancestry. Our stepwise conditional analyses revealed 238 independent association signals of CRC risk, each with a set of credible causal variants (CCVs), of which 28 signals had a single CCV. Our cis-eQTL/mQTL and colocalization analyses using colorectal tissue-specific transcriptome and methylome data separately from 1299 and 321 individuals, along with functional genomic investigation, uncovered 136 putative CRC susceptibility genes, including 56 genes not previously reported. Analyses of single-cell RNA-seq data from colorectal tissues revealed 17 putative CRC susceptibility genes with distinct expression patterns in specific cell types. Analyses of whole exome sequencing data provided additional support for several target genes identified in this study as CRC susceptibility genes. Enrichment analyses of the 136 genes uncover pathways not previously linked to CRC risk. Our study substantially expanded association signals for CRC and provided additional insight into the biological mechanisms underlying CRC development.

Variation in KRAS/NRAS/BRAF-Mutation Status by Age, Sex, and Race/Ethnicity Among a Large Cohort of Patients with Metastatic Colorectal Cancer (mCRC)

BACKGROUND

Racial/ethnic disparities in metastatic colorectal cancer (mCRC) survival are well documented as is the impact that tumor mutation of KRAS and BRAF has on prognosis. It has been suggested that frequency differences of KRAS- and BRAF-mutated tumors may partially explain this disparity. Demographic differences in mutation frequency are not well established nor whether mutation and microsatellite instability (MSI) differentially impact survival among groups.

METHODS

Using data for 11,117 patients diagnosed with de-novo mCRC from an electronic health record-derived database we estimated adjusted odds ratios (aOR) to characterize the association between demographics and MSI and KRAS/NRAS/BRAF-mutation status. Stratified Cox models were used to identify differences in overall survival (OS), adjusting for treatment and demographics.

RESULTS

Being female, compared to male, (aORKRAS:1.33 (1.23-1.44); aORBRAF:1.84 (1.56-2.16)), and non-Hispanic Black race (NHB), compared to non-Hispanic White (NHW) (aORKRAS:1.62 (1.42-1.85); aORBRAF: 0.55 (0.38-0.77)) were associated with KRAS- or BRAF-mutant tumors. MSI prevalence was similar across race/ethnicity but higher in women. BRAF-mutant tumors were associated with poorer prognosis overall, especially among non-white patients. Among patients who had KRAS/NRAS/BRAF-WT tumors we observed no difference in OS by race or MSI. Among patients with KRAS-mutant tumors, Hispanic patients had more favorable prognosis adjusted hazards ratio (aHR) = 0.76 (0.65-0.89)) than their NHW counterparts. Among those with BRAF-mutant tumors, NHB patients had poorer prognosis than NHW patients (aHR:1.78 (1.08-2.93)).

CONCLUSION

MSI and frequency of KRAS and BRAF mutations differed by demographics. Racial/ethnic disparities in OS differed by mutation. Future studies should explore biological and/or social determinants underlying these differences.

Recurrent urinary tract infection genetic risk: a systematic review and gene network analysis

INTRODUCTION AND HYPOTHESIS

The development of recurrent urinary tract infections (rUTIs) is not completely understood. This review is aimed at investigating the connection between genetics and rUTIs and summarizing the results of studies that have documented variations in gene expression among individuals with rUTIs compared with healthy individuals.

METHODS

A systematic search was conducted in Cochrane, Ovid, and PubMed, limiting the results to articles published between 1 January 2000, and 5 July 2022. Only studies comparing the difference in gene expression between individuals with rUTI and healthy individuals utilizing molecular techniques to measure gene expression in blood or urine samples were included in this systematic review. Gene network and pathways analyses were performed using Cytoscape software, with input data obtained from our systematic review of differentially expressed genes in rUTIs.

RESULTS

Six studies met our criteria for inclusion. The selected studies used molecular biology methods to quantify gene expression data from blood specimens. The analysis revealed that gene expressions of CXCR1 and TLR4 decreased, whereas CXCR2, TRIF, and SIGIRR increased in patients with rUTI compared with healthy controls. The analysis demonstrated that the most significant pathways were associated with TLR receptor signaling and tolerance, I-kappa B kinase/NF-kappa B signaling, and MyD88-independent TLR signaling.

CONCLUSIONS

This systematic review uncovered gene expression variations in several candidate genes and identified a number of underlying biological pathways associated with rUTIs. These findings could shift the treatment and prevention strategies for rUTIs.

Combining Asian and European genome-wide association studies of colorectal cancer improves risk prediction across racial and ethnic populations

Polygenic risk scores (PRS) have great potential to guide precision colorectal cancer (CRC) prevention by identifying those at higher risk to undertake targeted screening. However, current PRS using European ancestry data have sub-optimal performance in non-European ancestry populations, limiting their utility among these populations. Towards addressing this deficiency, we expand PRS development for CRC by incorporating Asian ancestry data (21,731 cases; 47,444 controls) into European ancestry training datasets (78,473 cases; 107,143 controls). The AUC estimates (95% CI) of PRS are 0.63(0.62-0.64), 0.59(0.57-0.61), 0.62(0.60-0.63), and 0.65(0.63-0.66) in independent datasets including 1681-3651 cases and 8696-115,105 controls of Asian, Black/African American, Latinx/Hispanic, and non-Hispanic White, respectively. They are significantly better than the European-centric PRS in all four major US racial and ethnic groups (p-values < 0.05). Further inclusion of non-European ancestry populations, especially Black/African American and Latinx/Hispanic, is needed to improve the risk prediction and enhance equity in applying PRS in clinical practice.

imply: improving cell-type deconvolution accuracy using personalized reference profiles

Real-world clinical samples are often admixtures of signal mosaics from multiple pure cell types. Using computational tools, bulk transcriptomics can be deconvoluted to solve for the abundance of constituent cell types. However, existing deconvolution methods are conditioned on the assumption that the whole study population is served by a single reference panel, which ignores person-to-person heterogeneity. Here we present imply, a novel algorithm to deconvolute cell type proportions using personalized reference panels. imply can borrow information across repeatedly measured samples for each subject, and obtain precise cell type proportion estimations. Simulation studies demonstrate reduced bias in cell type abundance estimation compared with existing methods. Real data analyses on large longitudinal consortia show more realistic deconvolution results that align with biological facts. Our results suggest that disparities in cell type proportions are associated with several disease phenotypes in type 1 diabetes and Parkinson's disease. Our proposed tool imply is available through the R/Bioconductor package ISLET at https://bioconductor.org/packages/ISLET/.

Prostate cancer genetic alterations in Hispanic men

BACKGROUND

Differences in DNA alterations in prostate cancer among White, Black, and Asian men have been widely described. This is the first description of the frequency of DNA alterations in primary and metastatic prostate cancer samples of self-reported Hispanic men.

METHODS

We utilized targeted next-generation sequencing tumor genomic profiles from prostate cancer tissues that underwent clinical sequencing at academic centers (GENIE 11th). We decided to restrict our analysis to the samples from Memorial Sloan Kettering Cancer Center as it was by far the main contributor of Hispanic samples. The numbers of men by self-reported ethnicity and racial categories were analyzed via Fisher's exact test between Hispanic-White versus non-Hispanic White.

RESULTS AND LIMITATIONS

Our cohort consisted of 1412 primary and 818 metastatic adenocarcinomas. In primary adenocarcinomas, TMPRSS2 and ERG gene alterations were less common in non-Hispanic White men than Hispanic White (31.86% vs. 51.28%, p = 0.0007, odds ratio [OR] = 0.44 [0.27-0.72] and 25.34% vs. 42.31%, p = 0.002, OR = 0.46 [0.28-0.76]). In metastatic tumors, KRAS and CCNE1 alterations were less prevalent in non-Hispanic White men (1.03% vs. 7.50%, p = 0.014, OR = 0.13 [0.03, 0.78] and 1.29% vs. 10.00%, p = 0.003, OR = 0.12 [0.03, 0.54]). No significant differences were found in actionable alterations and androgen receptor mutations between the groups. Due to the lack of clinical characteristics and genetic ancestry in this dataset, correlation with these could not be explored.

CONCLUSION

DNA alteration frequencies in primary and metastatic prostate cancer tumors differ among Hispanic-White and non-Hispanic White men. Notably, we found no significant differences in the prevalence of actionable genetic alterations between the groups, suggesting that a significant number of Hispanic men could benefit from the development of targeted therapies.

Population genetics analysis of SLC3A1 and SLC7A9 revealed the etiology of cystine stone may be more than what our current genetic knowledge can explain

BACKGROUND

Cystine stone is a Mendelian genetic disease caused by SLC3A1 or SLC7A9. In this study, we aimed to estimate the genetic prevalence of cystine stones and compare it with the clinical prevalence to better understand the disease etiology.

METHODS

We analyzed genetic variants in the general population using the 1000 Genomes project and the Human Gene Mutation Database to extract all SLC3A1 and SLC7A9 pathogenic variants. All variants procured from both databases were intersected. Pathogenic allele frequency, carrier rate, and affected rate were calculated and estimated based on Hardy-Weinberg equilibrium.

RESULTS

We found that 9 unique SLC3A1 pathogenic variants were carried by 26 people and 5 unique SLC7A9 pathogenic variants were carried by 12 people, all of whom were heterozygote carriers. No homozygote, compoun d heterozygote, or double heterozygote was identified in the 1000 Genome database. Based on the Hardy-Weinberg equilibrium, the calculated genetic prevalence of cystine stone disease is 1 in 30,585.

CONCLUSION

The clinical prevalence of cystine stone has been previously reported as 1 in 7,000, a notably higher figure than the genetic prevalence of 1 in 30,585 calculated in this study. This suggests that the etiology of cystine stone is more complex than what our current genetic knowledge can explain. Possible factors that may contribute to this difference include novel causal genes, undiscovered pathogenic variants, alternative inheritance models, founder effects, epigenetic modifications, environmental factors, or other modifying factors. Further investigation is needed to fully understand the etiology of cystine stone.

Novel correlative analysis identifies multiple genomic variations impacting ASD with macrocephaly

Autism spectrum disorders (ASD) display both phenotypic and genetic heterogeneity, impeding the understanding of ASD and development of effective means of diagnosis and potential treatments. Genes affected by genomic variations for ASD converge in dozens of gene ontologies (GOs), but the relationship between the variations at the GO level have not been well elucidated. In the current study, multiple types of genomic variations were mapped to GOs and correlations among GOs were measured in ASD and control samples. Several ASD-unique GO correlations were found, suggesting the importance of co-occurrence of genomic variations in genes from different functional categories in ASD etiology. Combined with experimental data, several variations related to WNT signaling, neuron development, synapse morphology/function and organ morphogenesis were found to be important for ASD with macrocephaly, and novel co-occurrence patterns of them in ASD patients were found. Furthermore, we applied this gene ontology correlation analysis method to find genomic variations that contribute to ASD etiology in combination with changes in gene expression and transcription factor binding, providing novel insights into ASD with macrocephaly and a new methodology for the analysis of genomic variation.

Disparities in cause-specific mortality by race and sex among bladder cancer patients from the SEER database

PURPOSE

Previous literature shows that more bladder cancer patients overall die from causes other than the primary malignancy. Given known disparities in bladder cancer outcomes by race and sex, we aimed to characterize differences in cause-specific mortality for bladder cancer patients by these demographics.

METHODS

We identified 215,252 bladder cancer patients diagnosed with bladder cancer from 2000 to 2017 in the SEER 18 database. We calculated cumulative incidence of death from seven causes (bladder cancer, COPD, diabetes, heart disease, external, other cancer, other) to assess differences in cause-specific mortality between race and sex subgroups. We used multivariable Cox proportional hazards regression and Fine-Gray competing risk models to compare risk of bladder cancer-specific mortality between race and sex subgroups overall and stratified by cancer stage.

RESULTS

17% of patients died from bladder cancer (n = 36,923), 30% died from other causes (n = 65,076), and 53% were alive (n = 113,253). Among those who died, the most common cause of death was bladder cancer, followed by other cancer and diseases of the heart. All race-sex subgroups were more likely than white men to die from bladder cancer. Compared to white men, white women (HR: 1.20, 95% CI: 1.17-1.23) and Black women (HR: 1.57, 95% CI: 1.49-1.66) had a higher risk of dying from bladder cancer, overall and stratified by stage.

CONCLUSION

Among bladder cancer patients, death from other causes especially other cancer and heart disease contributed a large proportion of mortality. We found differences in cause-specific mortality by race-sex subgroups, with Black women having a particularly high risk of dying from bladder cancer.

Combining Asian-European Genome-Wide Association Studies of Colorectal Cancer Improves Risk Prediction Across Race and Ethnicity

Polygenic risk scores (PRS) have great potential to guide precision colorectal cancer (CRC) prevention by identifying those at higher risk to undertake targeted screening. However, current PRS using European ancestry data have sub-optimal performance in non-European ancestry populations, limiting their utility among these populations. Towards addressing this deficiency, we expanded PRS development for CRC by incorporating Asian ancestry data (21,731 cases; 47,444 controls) into European ancestry training datasets (78,473 cases; 107,143 controls). The AUC estimates (95% CI) of PRS were 0.63(0.62-0.64), 0.59(0.57-0.61), 0.62(0.60-0.63), and 0.65(0.63-0.66) in independent datasets including 1,681-3,651 cases and 8,696-115,105 controls of Asian, Black/African American, Latinx/Hispanic, and non-Hispanic White, respectively. They were significantly better than the European-centric PRS in all four major US racial and ethnic groups (p-values<0.05). Further inclusion of non-European ancestry populations, especially Black/African American and Latinx/Hispanic, is needed to improve the risk prediction and enhance equity in applying PRS in clinical practice.

Receipt of Targeted Therapy and Survival Outcomes in Patients With Metastatic Colorectal Cancer

IMPORTANCE

Professional society guidelines recommend treating patients with metastatic colorectal cancer with targeted therapies, including epithelial growth factor receptor (EGFR) inhibitors and vascular endothelial growth factor (VEGF) inhibitors, depending on the presence or absence of certain mutations. Since most studies of first-line targeted therapies have been limited by sample size, there is a need for larger studies using data from routine clinical care.

OBJECTIVES

To identify factors associated with receipt of first-line targeted therapies among patients with metastatic colorectal cancer for whom RAS or BRAF mutation data in the tumor were available and investigate whether targeted therapy is associated with survival.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used deidentified data from an electronic health record-derived database to include patients from 800 sites of patient care across the US who were diagnosed with de novo metastatic colorectal cancer between January 1, 2013, and March 31, 2020 (n = 9134).

MAIN OUTCOMES AND MEASURES

Receipt of first-line targeted therapy, categorized as ever having received EGFR inhibitors, VEGF inhibitors, or neither. The secondary outcome was overall survival.

RESULTS

The study population included 9134 patients. The median age at diagnosis was 62 years (IQR, 53-71 years), 5019 (54.9%) were male, and 5692 (62.3%) were White. The median follow-up period was 15 months. Overall, 713 patients (7.8%) received EGFR inhibitors and 5081 patients (55.6%) received VEGF inhibitors as part of their first-line treatment. Among patients with RAS wild-type (RAS-WT) tumors, 625 patients (15.5%) received EGFR inhibitors and 2053 patients (50.9%) received VEGF inhibitors. In patients with RAS mutant (RAS-Mut) tumors, 50 patients (1.1%) received EGFR inhibitors and 2682 patients (59.7%) received VEGF inhibitors; among those with BRAF-mutant (BRAF-Mut) tumors, 38 patients (6.3%) received EGFR inhibitors and 346 patients (57.2%) received VEGF inhibitors. More than one-third of the patients (36.6%) received neither EGFR inhibitors nor VEGF inhibitors. Compared with patients younger than age 40 years, those aged 80 years or older had significantly lower odds to receive targeted therapies (EGFR or VEGF inhibitors in patients with RAS-WT tumors: adjusted odds ratio [aOR], 0.53; 95% CI, 0.36-0.79; and VEGF inhibitors in patients with RAS-Mut tumors: aOR, 0.62; 95% CI, 0.42-0.90). Improved survival was associated with EGFR inhibitor therapy in patients with RAS-WT tumors (adjusted hazard ratio [aHR], 0.85; 95% CI, 0.74-0.98). Unlike in clinical trials, however, no survival benefit was noted with use of VEGF inhibitors among patients with RAS-WT (aHR, 1.00; 95% CI, 0.91-1.11) or RAS-Mut (aHR, 1.01; 95% CI, 0.93-1.10) tumors.

CONCLUSIONS AND RELEVANCE

The findings of this study showed mixed results on survival benefits associated with targeted therapy. In addition, given that some of the results differed from those of randomized clinical trials, this study highlights the importance of using data originating from routine clinical care.

A systematic review and in silico study of potential genetic markers implicated in cases of overactive bladder

OBJECTIVE

The contribution of genetic factors to the presence of an overactive bladder is recognized. This study aimed to (1) assemble and synthesize available data from studies assessing differential gene expression in patients with overactive bladder vs controls without overactive bladder and (2) determine possible correlations and functional pathways between genes.

DATA SOURCES

We searched PubMed, Ovid or Medline, and Wiley Cochrane Central Register of Controlled Trials databases between January 1, 2000, and December 15, 2021.

STUDY ELIGIBILITY CRITERIA

Studies were included if gene expression was detected and quantified using molecular approaches performed on human bladder tissue specimens directly and excluded if the gene expression analysis was carried out from blood and urine specimens alone.

METHODS

A systematic review was completed to identify publications that reported differently expressed gene candidates among patients with overactive bladder vs healthy individuals. Gene networking connections and pathway analysis were performed employing Metascape software, where inputs were identified from our systematic review of differentially expressed genes in overactive bladder.

RESULTS

A total of 9 studies were included in the final analysis and 11 genes were identified as being up-regulated (purinergic receptor P2X 2 [P2RX2], smoothelin [SMTN], growth-associated protein 43 [GAP43], transient receptor potential cation channel subfamily M member 8 [TRPM8], cadherin 11 [CDH1], gap junction protein gamma 1 [GJC1], cholinergic receptor muscarinic 2 [CHRM2], cholinergic receptor muscarinic 3 [CHRM3], and transient receptor potential cation channel subfamily V member 4 [TRPV4]) or down-regulated (purinergic receptor P2X 2 [P2RX3] and purinergic receptor P2X 5 [P2RX5]) in patients with overactive bladder. Gene network analysis showed that genes are involved in chemical synaptic transmission, smooth muscle contraction, blood circulation, and response to temperature stimulus. Network analysis demonstrated a significant genetic interaction between TRPV4, TRPM8, P2RX3, and PR2X2 genes.

CONCLUSION

Outcomes of this systematic review highlighted potential biomarkers for treatment efficacy and have laid the groundwork for developing future gene therapies for overactive bladder in clinical settings.

A preliminary evaluation of in vivo response to a filament-wound macroporous collagen midurethral sling in an ovine model

Stress urinary incontinence (SUI) impacts ~1/3 of women over age 50. Negative publicity around PP meshes used in pelvic prolapse repair drives the need for identifying alternative biomaterials for SUI repair. Our study evaluated in vivo response to collagen sling implanted in an ovine model. Electrocompacted collagen threads were filament wound as slings and crosslinked in genipin. Collagen slings were implanted suburethrally mimicking the transvaginal tape technique. Main study groups were: Collagen sling (n = 3, 6 months) and PP sling (n = 3, 6 months). Collagen sling was also tested at 3-weeks (n = 1) to observe early-stage tissue response and 1-year (n = 2) to assess biomaterial longevity in a preliminary capacity. Collagen slings healed to a fibrous ligament texture at 6 months and maintained such texture to 1 year. Histological scoring indicated biocompatible responses to collagen slings with no adverse events. All study groups exhibited complete tissue ingrowth and interstitial de novo collagen deposition at all time points. Collagen threads induced orderly de novo collagen deposition that was aligned along long axes of threads. Tissue infiltrated collagen slings that were explanted at 6 and 12 months presented similar structural strength with native tissues such as vagina and fascia, and PP (Lynx) slings (p > .05). With the limitation of low number of animals per time point in hindsight, this preliminary study justifies evaluation of collagen slings in a larger sample size of animals, particularly to assess persistence of ligamentous tissue response over longer durations than 1-year.

Association Between Adrenal-Restrictive HSD3B1 Inheritance and Hormone-Independent Subtypes of Endometrial and Breast Cancer

BACKGROUND

The germline variant rs1047303 (HSD3B1[1245A/C]), restricting or enabling production of potent androgens and estrogens from adrenal precursors, affects outcomes of castration-resistant prostate cancer and is associated with estrogen receptor positivity in postmenopausal breast cancer. Like breast cancer, endometrial cancer is another malignancy with hormone-dependent and hormone-independent subtypes. We hypothesized that adrenal-restrictive HSD3B1 genotype would associate with hormone-independent cancer subtypes.

METHODS

We employed a previously described classification of tumors in The Cancer Genome Atlas into genomic clusters. We determined HSD3B1 genotype frequencies by endometrial cancer genomic cluster and calculated the odds per adrenal-restrictive A allele for the largely hormone-independent copy-number (CN) high subtype vs other subtypes. An equivalent analysis was performed for the genomically similar, hormone-independent basal breast cancer subtype. Last, we performed survival analyses for UK Biobank participants with endometrial cancer by HSD3B1 genotype. All statistical tests were 2-sided.

RESULTS

The adrenal-restrictive HSD3B1(1245A) allele was associated with the CN-high endometrial cancer subtype (odds ratio [OR] = 1.63, 95% confidence interval [CI] = 1.14 to 2.32; P = .007). Similarly, HSD3B1(1245A) was associated with the basal breast cancer subtype (OR = 1.54, 95% CI = 1.13 to 2.08; P = .006). In the UK Biobank, endometrial cancer patients homozygous for HSD3B1(1245A) had worse overall (hazard ratio [HR] = 1.39, 95% CI = 1.16 to 1.68; P < .001) and cancer-specific (HR = 1.39, 95% CI = 1.14 to 1.70; P = .001) survival, consistent with the A allele being enriched in the more aggressive CN-high subtype.

CONCLUSIONS

These findings suggest roles for adrenal-restrictive vs adrenal-permissive steroidogenesis, by way of rs1047303 genotype, in the development of and/or outcomes from at least 3 commonly hormone-associated types of cancer: prostate, breast, and endometrial.

Race and prostate cancer: genomic landscape

In the past 20 years, new insights into the genomic pathogenesis of prostate cancer have been provided. Large-scale integrative genomics approaches enabled researchers to characterize the genetic and epigenetic landscape of prostate cancer and to define different molecular subclasses based on the combination of genetic alterations, gene expression patterns and methylation profiles. Several molecular drivers of prostate cancer have been identified, some of which are different in men of different races. However, the extent to which genomics can explain racial disparities in prostate cancer outcomes is unclear. Future collaborative genomic studies overcoming the underrepresentation of non-white patients and other minority populations are essential.

Sociodemographic and clinical factors associated with receipt of biomarker testing in patients with metastatic colorectal cancer

BACKGROUND

Standard clinical practice and national guidelines dictate somatic testing of metastatic colorectal cancer (mCRC) tumors to guide appropriate therapy; however, previous studies suggest that not all patients are tested. The objective of this study was to investigate potential differences in testing for mCRC by demographic and clinical factors.

METHODS

We performed a retrospective review of de-identified patient data derived from electronic health records (EHRs) of 25,469 patients diagnosed with mCRC between the years 2013 and 2020. Our outcome was a receipt of the following tests: (a) biomarker testing (BRAF, KRAS, NRAS, MMR/MSI) and (b) next-generation sequencing (NGS). We interrogated our data using the machine-learning algorithm Classification and Regression Tree (CART), a unique approach to identifying combinations of, rather than individual demographic and clinical characteristics associated with receipt of testing.

RESULTS

A total of 25,469 patients were identified with mCRC. Of these, 21,133 (83%) received either biomarker testing only (n = 12,485) or any testing (biomarker + NGS) (n = 8648). The proportion of patients who received any testing increased over calendar time for all age, race, and sex categories. Receipt of any testing was highest (90%) among younger and patients with better performance status, and there was no difference in receipt of any testing by race. The highest percentage of NGS testing was among those with better performance status, <70 years old, commercial or other governmental program payers, and low comorbidity burden; however, those who were Black or Hispanic had a lower prevalence of NGS testing than those who were White.

CONCLUSIONS AND RELEVANCE

Considerable variations exist in somatic biomarker testing across subgroups of the population. Identification of genomic alterations can aid in determining targeted treatment and improving clinical outcomes; therefore, equitable use of these testing strategies, particularly NGS, is necessary.

Abstract 4126: Treatment and survival of patients with de novo metastatic colorectal cancer (mCRC) rested for KRAS, NRAS or BRAF mutations

Study Purpose: Molecular profiling of RAS (KRAS, NRAS) and BRAF mutations in mCRC is recommended by national guidelines to inform targeted treatment. The purpose of this study was to determine whether results of genomic testing are associated with receipt of targeted therapy (i.e. VEGFi and EGFRi), and whether receipt of first-line targeted therapy is associated with survival among patients with mCRC.

Methods: Using the nationwide de-identified electronic health record-derived Flatiron Health database, we included 10,168 patients with de novo mCRC diagnosed between 2013-2020 and tested for at least one of the above biomarkers at any time. We used multivariable Cox proportional hazards regression models, beginning follow-up at date of metastatic diagnosis and continued until death or end of follow-up, adjusted for age, sex, race/ethnicity, mutation status (mutant vs. wild type (WT)), tumor site (colon vs. rectum), mismatch repair (MMR), comorbidities, ECOG status, payer type, and first-line (1L) treatment, to investigate the associations between: 1) mutation status and 1L treatment; and 2) 1L treatment and overall survival.

Results: Overall, 9.5% did not have documented 1L treatment. Among patients with 1L treatment documented (n=9,202), the most common were FOLFOX+VEGFi (36.3%), followed by FOLFOX alone (15.8%), single-agent capecitabine (7.2%), and FOLFIRI+VEGFi (5.0%). After adjusting for treatment, patients with KRAS, NRAS, and BRAF mutant tumors had worse survival than those WT for all three: (HR: 1.32, 95% confidence interval: 1.23-1.42), (HR: 1.23, 95% CI: 1.04-1.47), and (HR: 1.77, 95% CI: 1.57-2.00), respectively. Of patients with RAS mutations, 59.8% received VEGFi, regardless of chemotherapy backbone. Contrary to outcomes reported from clinical trials, we observed similar survival in patients treated with VEGFi, compared to those without (HR: 1.03, (0.95-1.12)). Among patients with RAS WT tumors, 51.6% received VEGFi, but had no survival benefits (HR:1.06 (0.96-1.17)). About 1% of patients RAS mutant and 15.9% of RAS WT tumors received EGFRi regardless of chemotherapy backbone, and experienced better survival than those treated with VEGFi (HR: 0.88 (0.77-1.00). We observed no differences in survival by treatment among those with BRAF mutations.

Conclusions: Treatment with VEGFi was common. However, contrary to survival data from clinical trials, which exclude vulnerable populations, patients treated with VEGFi did not experience survival benefits, highlighting the importance of examining survival outcomes in routine clinical care. In patients with RAS WT tumors, treatment with EGFRi was associated with improved survival compared with those treated with VEGFi. Future studies should incorporate tumor sidedness and contraindications to determine appropriateness of treatment with VEGFi or EGFRi in patients with mCRC.

Citation Format: Ben D. Booker, Sarah C. Markt, Fredrick R. Schumacher, Johnie Rose, Greg S. Cooper, J Eva Selfridge, Siran M. Koroukian. Treatment and survival of patients with de novo metastatic colorectal cancer (mCRC) rested for KRAS, NRAS or BRAF mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4126.

Abstract 3676: Race-specific methylation profiles and epigenetic age acceleration differentiates estrogen receptor status breast cancer

Breast cancer (BrCa) is the second most common cancer among women in the U.S.. Black women with BrCa, on average, have an earlier age of onset, more aggressive subtypes and experience higher mortality compared with White women. Although the underlying causes remain unknown, genetic and lifetime exposures are hypothesized. Here, we utilize blood-based whole-genome methylation arrays to: (1) discover CpG probes related to BrCa receptor status, (2) identify biological pathways driving BrCa subtype disparities, and (3) quantify epigenetic age acceleration differences by race and receptor status.

DNA methylation levels were generated for 95 blood samples from women diagnosed with BrCa using the Illumina EPIC array. After quality control, M-values for 91 samples and 808,329 methylation probes were evaluated using a modified Student t-test. BrCa estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) status were collected from health records. Stratified analyses by race adjusting for age were applied. We calculated the association of age acceleration, based on Horvath’s epigenetic clock, by race and receptor status. Statistical significance, corrected for multiple testing, was defined as a p-valueadj &lt;0.05.

Among the 91 BrCa samples, nearly half were Black women (40.7%) and the overall mean age at diagnosis was 56.5 years ±11.3. The majority of BrCa tumors were ER-, 60.4% (N=55), and HER2-, 76.9% (N=70). Overall, two methylation probes significantly differentiated ER+/- BrCa. The most significant methylated gene was FOXK2 (p-valueadj=0.03, logFC=0.63). The race-stratified analysis identified 188,398 probes for ER+/- and five probes for HER2+/- among White women as marginally significant (p&lt;0.05). Two genes (FAM107B, PRKCZ) for ER+/- BrCa and four genes (ZNF430, TTC27, SEC1 and NOS1AP) for HER2+/- BrCa remained statistically significant after correcting for multiple comparisons (p-valueadj &lt; 0.05; |logFC| &gt;1). The mean age acceleration is estimated as 3.7 years greater for Black women compared to White women. Among White women, the mean age acceleration was 1.9 years greater for ER+ than ER- subtypes, and those HER2- were 2.2 years older than HER2+. Similarly, among Black women the mean age acceleration difference for ER- was 3.2 years greater than ER+, and HER2- was 3.8 years older than HER2+.

Our study confirmed (e.g. FOXK2) and identified several novel methylation sites associated with BrCa subtypes. Furthermore, we demonstrated in our study that epigenetic age acceleration of BrCa varies by race, with Black women biologically aging faster than White women. Although this is a limited sample size, stratified analyses revealed biological age differences by race and receptor status. In-depth pathway analyses and measuring additional samples are underway. Lastly, differential methylation profiles for known risk factors of aggressive tumors will be evaluated.

Citation Format: Yanning Wu, Cheryl L. Thompson, Fredrick R. Schumacher. Race-specific methylation profiles and epigenetic age acceleration differentiates estrogen receptor status breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3676.

Evaluating the estimation of genetic correlation and heritability using summary statistics

While novel statistical methods quantifying the shared heritability of traits and diseases between ancestral distinct populations have been recently proposed, a thorough evaluation of these approaches under differing circumstances remain elusive. Brown et al.2016 proposed the method Popcorn to estimate the shared heritability, i.e. genetic correlation, using only summary statistics. Here, we evaluate Popcorn under several parameters and circumstances: sample size, number of SNPs, sample size of external reference panel, various population pairs, inappropriate external reference panel, and admixed population involved. Our results determined the minimum sample size of the external reference panel, summary statistics, and number of SNPs required to accurately estimate both the genetic correlation and heritability. Moreover, the number of individuals and SNPs required to produce accurate and stable estimates was directly proportional with heritability in Popcorn. Misrepresentation of the reference panel overestimated the genetic correlation by 20% and heritability by 60%. Lastly, applying Popcorn to homogeneous (EUR) and admixed (ASW) populations underestimated the genetic correlation by 15%. Although statistical approaches estimating the shared heritability between ancestral populations will provide novel etiologic insight, caution is required ensuring results are based on the appropriate sample size, number of SNPs, and the generalizability of the reference panel to the discovery populations.

Data Matching to Support Analysis of Cancer Epidemiology Among Veterans Compared With Non-Veteran Populations-An Exemplar in Brain Tumors

PURPOSE

State and national cancer registries do not systematically include Veteran data, which hinders analysis of the diagnosis patterns, treatment trajectories, and clinical outcomes of Veterans compared with non-Veteran populations. This study used data matching approaches to compare cases included in the Oncology Domain of the Veterans Affairs (VA) Corporate Data Warehouse and the Ohio Cancer Incidence Surveillance System, using brain tumors as an exemplar.

METHODS

We used direct data matching, on the basis of protected health information (PHI) common to both databases, to compare primary brain tumors from Veterans and non-Veterans diagnosed from 2000 to 2016. Working with this matched data set, we used six data elements that did not contain PHI, to assess the feasibility of using deterministic data matching to compare Veterans and non-Veterans.

RESULTS

Between 2000 and 2016, 223 Veterans from Ohio had a primary brain tumor; of those, 55 (25%) were not included in Ohio Cancer Incidence Surveillance System. Direct data matching showed that Veterans experienced a greater proportion of glioblastomas (41%) compared with non-Veterans (21%). Sex did not account for this difference. Deterministic data matching within the matched data set found that 75% (126 of 168) of Veterans had exact matches for at least five of six non-PHI variables common to both databases.

CONCLUSION

This study indicated that direct and deterministic data matching approaches to compare brain tumors in Veterans and in non-Veterans is feasible. This approach has the potential to promote comparisons of the distribution of tumors, the impact of chemical and environmental exposures, treatment trajectories, and clinical outcomes among Veteran and non-Veteran populations with brain tumors as well as other cancers and rare diseases.

Large-scale cross-cancer fine-mapping of the 5p15.33 region reveals multiple independent signals

Genome-wide association studies (GWASs) have identified thousands of cancer risk loci revealing many risk regions shared across multiple cancers. Characterizing the cross-cancer shared genetic basis can increase our understanding of global mechanisms of cancer development. In this study, we collected GWAS summary statistics based on up to 375,468 cancer cases and 530,521 controls for fourteen types of cancer, including breast (overall, estrogen receptor [ER]-positive, and ER-negative), colorectal, endometrial, esophageal, glioma, head/neck, lung, melanoma, ovarian, pancreatic, prostate, and renal cancer, to characterize the shared genetic basis of cancer risk. We identified thirteen pairs of cancers with statistically significant local genetic correlations across eight distinct genomic regions. Specifically, the 5p15.33 region, harboring the TERT and CLPTM1L genes, showed statistically significant local genetic correlations for multiple cancer pairs. We conducted a cross-cancer fine-mapping of the 5p15.33 region based on eight cancers that showed genome-wide significant associations in this region (ER-negative breast, colorectal, glioma, lung, melanoma, ovarian, pancreatic, and prostate cancer). We used an iterative analysis pipeline implementing a subset-based meta-analysis approach based on cancer-specific conditional analyses and identified ten independent cross-cancer associations within this region. For each signal, we conducted cross-cancer fine-mapping to prioritize the most plausible causal variants. Our findings provide a more in-depth understanding of the shared inherited basis across human cancers and expand our knowledge of the 5p15.33 region in carcinogenesis.

Genetic architectures of proximal and distal colorectal cancer are partly distinct

OBJECTIVE

An understanding of the etiologic heterogeneity of colorectal cancer (CRC) is critical for improving precision prevention, including individualized screening recommendations and the discovery of novel drug targets and repurposable drug candidates for chemoprevention. Known differences in molecular characteristics and environmental risk factors among tumors arising in different locations of the colorectum suggest partly distinct mechanisms of carcinogenesis. The extent to which the contribution of inherited genetic risk factors for CRC differs by anatomical subsite of the primary tumor has not been examined.

DESIGN

To identify new anatomical subsite-specific risk loci, we performed genome-wide association study (GWAS) meta-analyses including data of 48 214 CRC cases and 64 159 controls of European ancestry. We characterised effect heterogeneity at CRC risk loci using multinomial modelling.

RESULTS

We identified 13 loci that reached genome-wide significance (p<5×10-8) and that were not reported by previous GWASs for overall CRC risk. Multiple lines of evidence support candidate genes at several of these loci. We detected substantial heterogeneity between anatomical subsites. Just over half (61) of 109 known and new risk variants showed no evidence for heterogeneity. In contrast, 22 variants showed association with distal CRC (including rectal cancer), but no evidence for association or an attenuated association with proximal CRC. For two loci, there was strong evidence for effects confined to proximal colon cancer.

CONCLUSION

Genetic architectures of proximal and distal CRC are partly distinct. Studies of risk factors and mechanisms of carcinogenesis, and precision prevention strategies should take into consideration the anatomical subsite of the tumour.

Variation in the use of genomic testing in patients with metastatic colorectal cancer

e15557

Background: Oncology has greatly benefited from the use of clinical genomics to aid diagnostic and treatment decisions. To inform targeted therapy, standard practice dictates molecular testing of metastatic colorectal cancer (mCRC) tumors through genomic testing (GT), including molecular biomarker, single gene, or next-generation sequencing (NGS). While persisting disparities in CRC screening, treatment, and outcomes have been well described, little is known about differences in GT for mCRC. Using all-payer electronic health record-derived de-identified data from a real-world database generated from routine clinical care across the U.S., we identified combinations of demographic and clinical characteristics, rather than individual factors, associated with GT. Methods: This study used the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database. During the study period, the de-identified data originated from approximately 280 US cancer clinics (̃800 sites of care). Our study population included 26,524 patients with mCRC during the years 2013-2020. We evaluated documentation of receipt of GT (individual biomarker or NGS) measured within one year of diagnosis of metastatic disease, by demographic (age, sex, and race/ethnicity), payer type, de novo metastatic cancer (vs. progression to metastatic disease), tumor site (colon vs. rectum), Eastern Cooperative Oncology Group (ECOG) performance status, and year of diagnosis. We identified Elixhauser comorbid conditions from ICD codes, and grouped them by count (0-4, 5+). We conducted Classification and Regression Tree (CART) analysis, a machine learning approach to identify combinations of demographic and clinical characteristics associated with receipt of GT. Results: Nearly 83% had documented GT, 90% of whom did so within 6 months of diagnosis. The largest group of patients with GT at 90% consisted of individuals with colon cancer, 64 years of age or younger, 0-4 comorbidities, and an ECOG score of 0 or 1 (n = 2,004). Conversely, the lowest rates of GT ( < 60%) were observed among women 75 years of age or older, despite having 0-4 comorbidities (n = 1,314). In this group of patients, GT was higher among those with ECOG score of 1 than among those with high ECOG scores (66% and 54%, respectively). On the other hand, 71% of patients 75 years of age or older with 5+ comorbidities and high ECOG scores received GT. Conclusions: Considerable variations exist in GT across subgroups of the population. Additional analysis is warranted to characterize young and healthy patients who did not receive GT, and those who did get tested despite their older age and compromised health status. Future analyses will investigate whether documentation of receipt of GT is associated with treatment decisions and outcomes.

Receipt of Next-generation Genomic Sequencing among Patients with Metastatic Colorectal Cancer (mCRC) in a Real-World Cohort

Purpose of the Study: Disparities in genomic precision medicine approaches, through molecular profiling or next- generation sequencing (NGS), by race/ethnicity, insurance, and poverty have been identified in lung cancer, but not mCRC. Our goal was to examine disparities in receipt of NGS in patients with mCRC. Methods: We used all-payer electronic health record (EHR)-derived de-identified data from the Flatiron Health database generated from routine clinical care across the United States. Our study population included 26,524 patients with mCRC during the years 2013–2020. In addition to date of NGS testing, the FH-EHR data include demographics (age, sex, and race/ethnicity), payer type, and Eastern Cooperative Oncology Group (ECOG) performance status. We conducted descriptive analyses and multivariable logistic regression analysis to identify correlates of receipt of NGS within 6 months of metastatic diagnosis. Results: Among the 26,524 people with mCRC, 45% (n = 11,946) were women, 48% (n = 12,732) had a Commercial Health Plan, and the majority were seen in a community practice (92%) vs academic hospitals. Over 70% of the patients were White, 12% Black or African-American (AA), and 14% Other. Thirty-three percent (n = 8,821) of patients had documentation in the EHR of having received NGS. After simultaneously adjusting for other factors in the model, older age (ORper year increase: 0.97, 95% CI: 0.96–0.98) and Black/AA race (OR: 0.74, 95% CI: 0.68–0.81), compared to White, was associated with lower odds of receiving NGS testing. Conversely, female sex, better ECOG performance status, later calendar year, being seen in an academic practice, and having a Commercial Health Plan were associated with greater odds of receiving NGS. Conclusions: Our findings indicate that NGS is not received uniformly by all patients with mCRC. Future analyses will incorporate receipt of individual molecular biomarker tests, as recommended by professional societies, as well as their results (e.g., KRAS, NRAS, BRAF, MMR/MSI), treatment information, and survival.

Identifying Novel Susceptibility Genes for Colorectal Cancer Risk From a Transcriptome-Wide Association Study of 125,478 Subjects

BACKGROUND AND AIMS

Susceptibility genes and the underlying mechanisms for the majority of risk loci identified by genome-wide association studies (GWAS) for colorectal cancer (CRC) risk remain largely unknown. We conducted a transcriptome-wide association study (TWAS) to identify putative susceptibility genes.

METHODS

Gene-expression prediction models were built using transcriptome and genetic data from the 284 normal transverse colon tissues of European descendants from the Genotype-Tissue Expression (GTEx), and model performance was evaluated using data from The Cancer Genome Atlas (n = 355). We applied the gene-expression prediction models and GWAS data to evaluate associations of genetically predicted gene-expression with CRC risk in 58,131 CRC cases and 67,347 controls of European ancestry. Dual-luciferase reporter assays and knockdown experiments in CRC cells and tumor xenografts were conducted.

RESULTS

We identified 25 genes associated with CRC risk at a Bonferroni-corrected threshold of P < 9.1 × 10-6, including genes in 4 novel loci, PYGL (14q22.1), RPL28 (19q13.42), CAPN12 (19q13.2), MYH7B (20q11.22), and MAP1L3CA (20q11.22). In 9 known GWAS-identified loci, we uncovered 9 genes that have not been reported previously, whereas 4 genes remained statistically significant after adjusting for the lead risk variant of the locus. Through colocalization analysis in GWAS loci, we additionally identified 12 putative susceptibility genes that were supported by TWAS analysis at P < .01. We showed that risk allele of the lead risk variant rs1741640 affected the promoter activity of CABLES2. Knockdown experiments confirmed that CABLES2 plays a vital role in colorectal carcinogenesis.

CONCLUSIONS

Our study reveals new putative susceptibility genes and provides new insight into the biological mechanisms underlying CRC development.

Rare Variants in the DNA Repair Pathway and the Risk of Colorectal Cancer

BACKGROUND

Inherited susceptibility is an important contributor to colorectal cancer risk, and rare variants in key genes or pathways could account in part for the missing proportion of colorectal cancer heritability.

METHODS

We conducted an exome-wide association study including 2,327 cases and 2,966 controls of European ancestry from three large epidemiologic studies. Single variant associations were tested using logistic regression models, adjusting for appropriate study-specific covariates. In addition, we examined the aggregate effects of rare coding variation at the gene and pathway levels using Bayesian model uncertainty techniques.

RESULTS

In an exome-wide gene-level analysis, we identified ST6GALNAC2 as the top associated gene based on the Bayesian risk index (BRI) method [summary Bayes factor (BF)_BRI = 2604.23]. A rare coding variant in this gene, rs139401613, was the top associated variant (P = 1.01 × 10^-6) in an exome-wide single variant analysis. Pathway-level association analyses based on the integrative BRI (iBRI) method found extreme evidence of association with the DNA repair pathway (BF_iBRI = 17852.4), specifically with the nonhomologous end joining (BF_iBRI = 437.95) and nucleotide excision repair (BF_iBRI = 36.96) subpathways. The iBRI method also identified RPA2, PRKDC, ERCC5, and ERCC8 as the top associated DNA repair genes (summary BF_iBRI ≥ 10), with rs28988897, rs8178232, rs141369732, and rs201642761 being the most likely associated variants in these genes, respectively.

CONCLUSIONS

We identified novel variants and genes associated with colorectal cancer risk and provided additional evidence for a role of DNA repair in colorectal cancer tumorigenesis.

IMPACT

This study provides new insights into the genetic predisposition to colorectal cancer, which has potential for translation into improved risk prediction.

Trans-ancestry genome-wide association meta-analysis of prostate cancer identifies new susceptibility loci and informs genetic risk prediction

Prostate cancer is a highly heritable disease with large disparities in incidence rates across ancestry populations. We conducted a multiancestry meta-analysis of prostate cancer genome-wide association studies (107,247 cases and 127,006 controls) and identified 86 new genetic risk variants independently associated with prostate cancer risk, bringing the total to 269 known risk variants. The top genetic risk score (GRS) decile was associated with odds ratios that ranged from 5.06 (95% confidence interval (CI), 4.84-5.29) for men of European ancestry to 3.74 (95% CI, 3.36-4.17) for men of African ancestry. Men of African ancestry were estimated to have a mean GRS that was 2.18-times higher (95% CI, 2.14-2.22), and men of East Asian ancestry 0.73-times lower (95% CI, 0.71-0.76), than men of European ancestry. These findings support the role of germline variation contributing to population differences in prostate cancer risk, with the GRS offering an approach for personalized risk prediction.

Assessment of polygenic architecture and risk prediction based on common variants across fourteen cancers

Genome-wide association studies (GWAS) have led to the identification of hundreds of susceptibility loci across cancers, but the impact of further studies remains uncertain. Here we analyse summary-level data from GWAS of European ancestry across fourteen cancer sites to estimate the number of common susceptibility variants (polygenicity) and underlying effect-size distribution. All cancers show a high degree of polygenicity, involving at a minimum of thousands of loci. We project that sample sizes required to explain 80% of GWAS heritability vary from 60,000 cases for testicular to over 1,000,000 cases for lung cancer. The maximum relative risk achievable for subjects at the 99th risk percentile of underlying polygenic risk scores (PRS), compared to average risk, ranges from 12 for testicular to 2.5 for ovarian cancer. We show that PRS have potential for risk stratification for cancers of breast, colon and prostate, but less so for others because of modest heritability and lower incidence.

Cumulative Burden of Colorectal Cancer-Associated Genetic Variants Is More Strongly Associated With Early-Onset vs Late-Onset Cancer

BACKGROUND & AIMS

Early-onset colorectal cancer (CRC, in persons younger than 50 years old) is increasing in incidence; yet, in the absence of a family history of CRC, this population lacks harmonized recommendations for prevention. We aimed to determine whether a polygenic risk score (PRS) developed from 95 CRC-associated common genetic risk variants was associated with risk for early-onset CRC.

METHODS

We studied risk for CRC associated with a weighted PRS in 12,197 participants younger than 50 years old vs 95,865 participants 50 years or older. PRS was calculated based on single nucleotide polymorphisms associated with CRC in a large-scale genome-wide association study as of January 2019. Participants were pooled from 3 large consortia that provided clinical and genotyping data: the Colon Cancer Family Registry, the Colorectal Transdisciplinary Study, and the Genetics and Epidemiology of Colorectal Cancer Consortium and were all of genetically defined European descent. Findings were replicated in an independent cohort of 72,573 participants.

RESULTS

Overall associations with CRC per standard deviation of PRS were significant for early-onset cancer, and were stronger compared with late-onset cancer (P for interaction = .01); when we compared the highest PRS quartile with the lowest, risk increased 3.7-fold for early-onset CRC (95% CI 3.28-4.24) vs 2.9-fold for late-onset CRC (95% CI 2.80-3.04). This association was strongest for participants without a first-degree family history of CRC (P for interaction = 5.61 × 10-5). When we compared the highest with the lowest quartiles in this group, risk increased 4.3-fold for early-onset CRC (95% CI 3.61-5.01) vs 2.9-fold for late-onset CRC (95% CI 2.70-3.00). Sensitivity analyses were consistent with these findings.

CONCLUSIONS

In an analysis of associations with CRC per standard deviation of PRS, we found the cumulative burden of CRC-associated common genetic variants to associate with early-onset cancer, and to be more strongly associated with early-onset than late-onset cancer, particularly in the absence of CRC family history. Analyses of PRS, along with environmental and lifestyle risk factors, might identify younger individuals who would benefit from preventive measures.

Germline genetic variation in prostate susceptibility does not predict outcomes in the chemoprevention trials PCPT and SELECT

Background

The development of prostate cancer can be influenced by genetic and environmental factors. Numerous germline SNPs influence prostate cancer susceptibility. The functional pathways in which these SNPs increase prostate cancer susceptibility are unknown. Finasteride is currently not being used routinely as a chemoprevention agent but the long term outcomes of the PCPT trial are awaited. The outcomes of the SELECT trial have not recommended the use of chemoprevention in preventing prostate cancer. This study investigated whether germline risk SNPs could be used to predict outcomes in the PCPT and SELECT trial.

Methods

Genotyping was performed in European men entered into the PCPT trial (n = 2434) and SELECT (n = 4885). Next generation genotyping was performed using Affymetrix® Eureka™ Genotyping protocols. Logistic regression models were used to test the association of risk scores and the outcomes in the PCPT and SELECT trials.

Results

Of the 100 SNPs, 98 designed successfully and genotyping was validated for samples genotyped on other platforms. A number of SNPs predicted for aggressive disease in both trials. Men with a higher polygenic score are more likely to develop prostate cancer in both trials, but the score did not predict for other outcomes in the trial.

Conclusion

Men with a higher polygenic risk score are more likely to develop prostate cancer. There were no interactions of these germline risk SNPs and the chemoprevention agents in the SELECT and PCPT trials.

Publisher Correction: Shared heritability and functional enrichment across six solid cancers

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Genome-wide association study of circulating folate one-carbon metabolites

Experimental, observational, and clinical trials support a critical role of folate one-carbon metabolism (FOCM) in colorectal cancer (CRC) development. In this report, we focus on understanding the relationship between common genetic variants and metabolites of FOCM. We conducted a genome-wide association study of FOCM biomarkers among 1,788 unaffected (without CRC) individuals of European ancestry from the Colon Cancer Family Registry. Twelve metabolites, including 5-methyltetrahydrofolate, vitamin B₂ (flavin mononucleotide and riboflavin), vitamin B₆ (4-pyridoxic acid, pyridoxal, and pyridoxamine), total homocysteine, methionine, S-adenosylmethionine, S-adenosylhomocysteine, cystathionine, and creatinine were measured from plasma using liquid chromatography-mass spectrometry (LC-MS) or LC-MS/MS. For each individual biomarker, we estimated genotype array-specific associations followed by a fixed-effect meta-analysis. We identified the variant rs35976024 (at 2p11.2 and intronic of ATOH8) associated with total homocysteine (p = 4.9 × 10^-8 ). We found a group of six highly correlated variants on chromosome 15q14 associated with cystathionine (all p < 5 × 10^-8 ), with the most significant variant rs28391580 (p = 2.8 × 10^-8 ). Two variants (rs139435405 and rs149119426) on chromosome 14q13 showed significant (p < 5 × 10^-8 ) associations with S-adenosylhomocysteine. These three biomarkers with significant associations are closely involved in homocysteine metabolism. Furthermore, when assessing the principal components (PCs) derived from seven individual biomarkers, we identified the variant rs12665366 (at 6p25.3 and intronic of EXOC2) associated with the first PC (p = 2.3 × 10^-8 ). Our data suggest that common genetic variants may play an important role in FOCM, particularly in homocysteine metabolism.

Gene expression in stress urinary incontinence: a systematic review

INTRODUCTION

A contribution of genetic factors to the development of stress urinary incontinence (SUI) is broadly acknowledged. This study aimed to: (1) provide insight into the genetic pathogenesis of SUI by gathering and synthesizing the available data from studies evaluating differential gene expression in SUI patients and (2) identify possible novel therapeutic targets and leads.

METHODS

A systematic literature search was conducted through September 2017 for the concepts of genetics and SUI. Gene networking connections and gene-set functional analyses of the identified genes as differentially expressed in SUI were performed using GeneMANIA software.

RESULTS

Of 3019 studies, 4 were included in the final analysis. A total of 13 genes were identified as being differentially expressed in SUI patients. Eleven genes were overexpressed: skin-derived antileukoproteinase (SKALP/elafin), collagen type XVII alpha 1 chain (COL17A1), plakophilin 1 (PKP1), keratin 16 (KRT16), decorin (DCN), biglycan (BGN), protein bicaudal D homolog 2 (BICD2), growth factor receptor-bound protein 2 (GRB2), signal transducer and activator of transcription 3 (STAT3), apolipoprotein E (APOE), and Golgi SNAP receptor complex member 1 (GOSR1), while two genes were underexpressed: fibromodulin (FMOD) and glucocerebrosidase (GBA). GeneMANIA revealed that these genes are involved in intermediate filament cytoskeleton and extracellular matrix organization.

CONCLUSION

Many genes are involved in the pathogenesis of SUI. Furthermore, whole-genome studies are warranted to identify these genetic connections. This study lays the groundwork for future research and the development of novel therapies and SUI biomarkers in clinical practice.

Lifetime Occurrence of Brain Metastases Arising from Lung, Breast, and Skin Cancers in the Elderly: A SEER-Medicare Study

BACKGROUND

The Surveillance, Epidemiology, and End Results (SEER) Program recently released data on brain metastases (BM) diagnosed during primary cancer staging workup ("synchronous" BM, or SBM); this study examines the incidence of SBM compared with that of lifetime BM (LBM) identified using Medicare claims for patients diagnosed with lung cancer, breast cancer, or melanoma.

METHODS

Incidence proportions (IP) and age-adjusted rates for each of SEER SBM and Medicare LBM are presented along with measures of concordance between the two sources of data, where Medicare LBM were defined by several combinations of diagnosis and putative diagnostic imaging procedure codes.

RESULTS

The SBM IP in lung, breast, and melanoma cancers were 9.6%, 0.3%, and 1.1%, respectively; the corresponding LBM IP were 13.5%, 1.8%, and 3.6%. The greatest SBM IP among patients with lung cancer was 13.4% for non-small cell lung cancer, and among patients with breast cancer was 0.7% for triple-negative breast cancer. The greatest LBM IP among lung cancers was 23.1% in small-cell lung cancer, and among breast cancers was 4.2% for cases of the triple negative subtype.

CONCLUSIONS

Using a large dataset that is representative of the elderly population in the United States, these analyses estimate synchronous and lifetime incidence of BM in lung cancers, breast cancers, and melanomas.

IMPACT

These and other population-based estimates may be used to guide development of BM screening policy and evaluation of real-world data sources.

Large-Scale Genome-Wide Association Study of East Asians Identifies Loci Associated With Risk for Colorectal Cancer

BACKGROUND & AIMS

Genome-wide association studies (GWASs) have associated approximately 50 loci with risk of colorectal cancer (CRC)-nearly one third of these loci were initially associated with CRC in studies conducted in East Asian populations. We conducted a GWAS of East Asians to identify CRC risk loci and evaluate the generalizability of findings from GWASs of European populations to Asian populations.

METHODS

We analyzed genetic data from 22,775 patients with CRC (cases) and 47,731 individuals without cancer (controls) from 14 studies in the Asia Colorectal Cancer Consortium. First, we performed a meta-analysis of 7 GWASs (10,625 cases and 34,595 controls) and identified 46,554 promising risk variants for replication by adding them to the Multi-Ethnic Global Array (MEGA) for genotype analysis in 6445 cases and 7175 controls. These data were analyzed, along with data from an additional 5705 cases and 5961 controls genotyped using the OncoArray. We also obtained data from 57,976 cases and 67,242 controls of European descent. Variants at identified risk loci were functionally annotated and evaluated in correlation with gene expression levels.

RESULTS

A meta-analyses of all samples from people of Asian descent identified 13 loci and 1 new variant at a known locus (10q24.2) associated with risk of CRC at the genome-wide significance level of P < 5 × 10-8. We did not perform experiments to replicate these associations in additional individuals of Asian ancestry. However, the lead risk variant in 6 of these loci was also significantly associated with risk of CRC in European descendants. A strong association (44%-75% increase in risk per allele) was found for 2 low-frequency variants: rs201395236 at 1q44 (minor allele frequency, 1.34%) and rs77969132 at 12p11.21 (minor allele frequency, 1.53%). For 8 of the 13 associated loci, the variants with the highest levels of significant association were located inside or near the protein-coding genes L1TD1, EFCAB2, PPP1R21, SLCO2A1, HLA-G, NOTCH4, DENND5B, and GNAS. For other intergenic loci, we provided evidence for the possible involvement of the genes ALDH7A1, PRICKLE1, KLF5, WWOX, and GLP2R. We replicated findings for 41 of 52 previously reported risk loci.

CONCLUSIONS

We showed that most of the risk loci previously associated with CRC risk in individuals of European descent were also associated with CRC risk in East Asians. Furthermore, we identified 13 loci significantly associated with risk for CRC in Asians. Many of these loci contained genes that regulate the immune response, Wnt signaling to β-catenin, prostaglandin E2 catabolism, and cell pluripotency and proliferation. Further analyses of these genes and their variants is warranted, particularly for the 8 loci for which the lead CRC risk variants were not replicated in persons of European descent.

Author Correction: Association analyses of more than 140,000 men identify 63 new prostate cancer susceptibility loci

In the version of this article initially published, the name of author Manuela Gago-Dominguez was misspelled as Manuela Gago Dominguez. The error has been corrected in the HTML and PDF version of the article.

Novel Common Genetic Susceptibility Loci for Colorectal Cancer

BACKGROUND

Previous genome-wide association studies (GWAS) have identified 42 loci (P < 5 × 10-8) associated with risk of colorectal cancer (CRC). Expanded consortium efforts facilitating the discovery of additional susceptibility loci may capture unexplained familial risk.

METHODS

We conducted a GWAS in European descent CRC cases and control subjects using a discovery-replication design, followed by examination of novel findings in a multiethnic sample (cumulative n = 163 315). In the discovery stage (36 948 case subjects/30 864 control subjects), we identified genetic variants with a minor allele frequency of 1% or greater associated with risk of CRC using logistic regression followed by a fixed-effects inverse variance weighted meta-analysis. All novel independent variants reaching genome-wide statistical significance (two-sided P < 5 × 10-8) were tested for replication in separate European ancestry samples (12 952 case subjects/48 383 control subjects). Next, we examined the generalizability of discovered variants in East Asians, African Americans, and Hispanics (12 085 case subjects/22 083 control subjects). Finally, we examined the contributions of novel risk variants to familial relative risk and examined the prediction capabilities of a polygenic risk score. All statistical tests were two-sided.

RESULTS

The discovery GWAS identified 11 variants associated with CRC at P < 5 × 10-8, of which nine (at 4q22.2/5p15.33/5p13.1/6p21.31/6p12.1/10q11.23/12q24.21/16q24.1/20q13.13) independently replicated at a P value of less than .05. Multiethnic follow-up supported the generalizability of discovery findings. These results demonstrated a 14.7% increase in familial relative risk explained by common risk alleles from 10.3% (95% confidence interval [CI] = 7.9% to 13.7%; known variants) to 11.9% (95% CI = 9.2% to 15.5%; known and novel variants). A polygenic risk score identified 4.3% of the population at an odds ratio for developing CRC of at least 2.0.

CONCLUSIONS

This study provides insight into the architecture of common genetic variation contributing to CRC etiology and improves risk prediction for individualized screening.

Shared heritability and functional enrichment across six solid cancers

Quantifying the genetic correlation between cancers can provide important insights into the mechanisms driving cancer etiology. Using genome-wide association study summary statistics across six cancer types based on a total of 296,215 cases and 301,319 controls of European ancestry, here we estimate the pair-wise genetic correlations between breast, colorectal, head/neck, lung, ovary and prostate cancer, and between cancers and 38 other diseases. We observed statistically significant genetic correlations between lung and head/neck cancer (rg = 0.57, p = 4.6 × 10-8), breast and ovarian cancer (rg = 0.24, p = 7 × 10-5), breast and lung cancer (rg = 0.18, p =1.5 × 10-6) and breast and colorectal cancer (rg = 0.15, p = 1.1 × 10-4). We also found that multiple cancers are genetically correlated with non-cancer traits including smoking, psychiatric diseases and metabolic characteristics. Functional enrichment analysis revealed a significant excess contribution of conserved and regulatory regions to cancer heritability. Our comprehensive analysis of cross-cancer heritability suggests that solid tumors arising across tissues share in part a common germline genetic basis.

Author Correction: Germline variation at 8q24 and prostate cancer risk in men of European ancestry

The original version of this Article contained an error in the spelling of the author Manuela Gago-Dominguez, which was incorrectly given as Manuela G. Dominguez. This has now been corrected in both the PDF and HTML versions of the Article.

Circulating Metabolic Biomarkers of Screen-Detected Prostate Cancer in the ProtecT Study

BACKGROUND

Whether associations between circulating metabolites and prostate cancer are causal is unknown. We report on the largest study of metabolites and prostate cancer (2,291 cases and 2,661 controls) and appraise causality for a subset of the prostate cancer-metabolite associations using two-sample Mendelian randomization (MR).

METHODS

The case-control portion of the study was conducted in nine UK centers with men ages 50-69 years who underwent prostate-specific antigen screening for prostate cancer within the Prostate Testing for Cancer and Treatment (ProtecT) trial. Two data sources were used to appraise causality: a genome-wide association study (GWAS) of metabolites in 24,925 participants and a GWAS of prostate cancer in 44,825 cases and 27,904 controls within the Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL) consortium.

RESULTS

Thirty-five metabolites were strongly associated with prostate cancer (P < 0.0014, multiple-testing threshold). These fell into four classes: (i) lipids and lipoprotein subclass characteristics (total cholesterol and ratios, cholesterol esters and ratios, free cholesterol and ratios, phospholipids and ratios, and triglyceride ratios); (ii) fatty acids and ratios; (iii) amino acids; (iv) and fluid balance. Fourteen top metabolites were proxied by genetic variables, but MR indicated these were not causal.

CONCLUSIONS

We identified 35 circulating metabolites associated with prostate cancer presence, but found no evidence of causality for those 14 testable with MR. Thus, the 14 MR-tested metabolites are unlikely to be mechanistically important in prostate cancer risk.

IMPACT

The metabolome provides a promising set of biomarkers that may aid prostate cancer classification.

Discovery of common and rare genetic risk variants for colorectal cancer

To further dissect the genetic architecture of colorectal cancer (CRC), we performed whole-genome sequencing of 1,439 cases and 720 controls, imputed discovered sequence variants and Haplotype Reference Consortium panel variants into genome-wide association study data, and tested for association in 34,869 cases and 29,051 controls. Findings were followed up in an additional 23,262 cases and 38,296 controls. We discovered a strongly protective 0.3% frequency variant signal at CHD1. In a combined meta-analysis of 125,478 individuals, we identified 40 new independent signals at P < 5 × 10-8, bringing the number of known independent signals for CRC to ~100. New signals implicate lower-frequency variants, Krüppel-like factors, Hedgehog signaling, Hippo-YAP signaling, long noncoding RNAs and somatic drivers, and support a role for immune function. Heritability analyses suggest that CRC risk is highly polygenic, and larger, more comprehensive studies enabling rare variant analysis will improve understanding of biology underlying this risk and influence personalized screening strategies and drug development.

Growth factor genes and change in mammographic density after stopping combined hormone therapy in the California Teachers Study

Background

The contribution of genetic polymorphisms to the large inter-individual variation in mammographic density (MD) changes following starting and stopping use of estrogen and progestin combined therapy (EPT) has not been well-studied. Previous studies have shown that circulating levels of insulin-like growth factors are associated with MD and cross-talk between estrogen signaling and growth factors is necessary for cell proliferation in the breast. We evaluated single nucleotide polymorphisms (SNPs) in growth factor genes in association with MD changes after women stop EPT use.

Methods

We genotyped 191 SNPs in 13 growth factor pathway genes in 284 non-Hispanic white California Teachers Study participants who previously used EPT and collected their mammograms before and after quitting EPT. Percent MD was assessed using a computer-assisted method. Change in percent MD was calculated by subtracting percent MD of an ‘off-EPT’ mammogram from percent MD of an ‘on-EPT’ (i.e. baseline) mammogram. We used multivariable linear regression analysis to investigate the association between SNPs and change in percent MD. We calculated P-values corrected for multiple testing within a gene (P_adj).

Results

Rs1983210 in INHA and rs35539615 in IGFBP1/3 showed the strongest associations. Per minor allele of rs1983210, the absolute change in percent MD after stopping EPT use decreased by 1.80% (a difference in absolute change in percent MD) (P_adj= 0.021). For rs35539615, change in percent MD increased by 1.79% per minor allele (P_adj= 0.042). However, after applying a Bonferroni correction for the number of genes tested, these associations were no longer statistically significant.

Conclusions

Genetic variation in growth factor pathway genes INHA and IGFBP1/3 may predict longitudinal MD change after women quit EPT. The observed differences in EPT-associated changes in percent MD in association with these genetic polymorphisms are modest but may be clinically significant considering that the magnitude of absolute increase in percent MD reported from large clinical trials of EPT ranged from 3% to 7%.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4981-6) contains supplementary material, which is available to authorized users.

Germline variation at 8q24 and prostate cancer risk in men of European ancestry

Chromosome 8q24 is a susceptibility locus for multiple cancers, including prostate cancer. Here we combine genetic data across the 8q24 susceptibility region from 71,535 prostate cancer cases and 52,935 controls of European ancestry to define the overall contribution of germline variation at 8q24 to prostate cancer risk. We identify 12 independent risk signals for prostate cancer (p < 4.28 × 10-15), including three risk variants that have yet to be reported. From a polygenic risk score (PRS) model, derived to assess the cumulative effect of risk variants at 8q24, men in the top 1% of the PRS have a 4-fold (95%CI = 3.62-4.40) greater risk compared to the population average. These 12 variants account for ~25% of what can be currently explained of the familial risk of prostate cancer by known genetic risk factors. These findings highlight the overwhelming contribution of germline variation at 8q24 on prostate cancer risk which has implications for population risk stratification.

Abstract 227: Germline variation at 8q24 and prostate cancer risk in men of European ancestry

We performed an in-depth and well-powered investigation of genetic variation across the cancer susceptibility region at chromosome 8q24 (127.6-129.0 Mb) to search for novel risk variants associated with prostate cancer (PCa) risk in the European ancestry population. We combined genotyped and imputed data from the PRACTICAL/ELLIPSE OncoArray and iCOGS consortia consisting of 71,535 PrCa cases and 52,935 controls of European ancestry. Variants with high imputation quality score (&gt;0.8) were retained for a total of 5,600 overlapping variants between the two datasets. Associations of genetic variants with PCa risk were evaluated using unconditional logistic regression with adjustment for country and ten principal components. The marginal risk estimates for the 5,600 variants that passed quality control were combined by a fixed effects meta-analysis. A meta-stepwise selection was performed on variants marginally associated with PCa risk from the meta results (P&lt;0.05). A polygenic risk score and the contribution to the familial relative risk of PCa were estimated for variants from the final model. Of the 5,600 variants at 8q24 retained for analysis, 1,268 (23%) were associated with PCa risk at P&lt;5x10-8 while 2,772 (49%) were marginally associated at P&lt;0.05. In the stepwise model, 12 variants remained statistically significantly associated with PCa risk with conditional meta p-values between 2.93x10-137 and 4.28x10-15. The independent stepwise signals were confirmed by Joint Analysis of Marginal (JAM) summary statistics, which defined the credible sets of variants driving those signals. Three of the variants (rs1914295, rs190257175, rs12549761) were weakly correlated (r2≤0.17) with any known PCa risk marker, and may define novel association signals. Men in the top 1% of the polygenic risk score distribution had a 3.97-fold relative risk (95%CI=3.87-4.07) compared to men with "average risk" (25th-75th percentiles). The 12 independent signals at 8q24 capture 11.54% (95%CI=9.86-13.65) of the familial relative risk of PCa, which is approximately one quarter of the total PCa familial relative risk explained by known genetic risk factors. Most of the independently associated signals have good evidence for biologic functionality; in particular, many reside within putative transcriptional enhancers and/or binding sites for AR and FOXA1 transcription factors in prostate cell lines. In summary, we defined 12 independent association signals among men of European ancestry, with three of the risk variants representing putative novel association signals. Whereas the individual associations of these variants with PCa risk are relatively modest (ORs&lt;2.0), their cumulative effects are substantial, and their contribution to the overall familial relative risk of PCa is substantially greater than any other known prostate cancer risk locus.

Citation Format: Marco Matejcic, Edward J. Saunders, Tokhir Dadaev, Mark Brook, Ali Amin Al Olama, Fredrick R. Schumacher, Sonja I. Berndt, Sara Benlloch, Kenneth Muir, Koveela Govindasami, Victoria L. Stevens, Susan M. Gapstur, Catherine M. Tangen, Jyotsna Batra, Judith Clements, APCB (Australian Prostate Cancer Bio Resource), Henrik Gronberg, Nora Pashayan, Johanna Schleutker, Demetrius Albanes, Alicja Wolk, Catharine West, Lorelei Mucci, Peter Kraft, Géraldine Cancel-Tassin, Stella Koutros, Karina Dalsgaard Sorensen, Lovise Maehle, Eli Marie Grindedal, Sara Strom, David E. Neal, Freddie C. Hamdy, Jenny L. Donovan, Ruth C. Travis, Robert J. Hamilton, Sue Ann Ingles, Barry Rosenstein, Yong-Jie Lu, Graham G. Giles, Adam S. Kibel, Ana Vega, Jeanette Bensen, Manolis Kogevinas, Fredrik Wiklund, Stephen Chanock, Douglas F. Easton, Rosalind A. Eeles, Zsofia Kote-Jarai, David V. Conti, Christopher A. Haiman. Germline variation at 8q24 and prostate cancer risk in men of European ancestry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 227.