Elissa C. Brown

Urinary TMPRSS2:ERG and PCA3 in an Active Surveillance Cohort: Results from a Baseline Analysis in the Canary Prostate Active Surveillance Study

Purpose: Active surveillance is used to manage low-risk prostate cancer. Both PCA3 and TMPRSS2:ERG are promising biomarkers that may be associated with aggressive disease. This study examines the correlation of these biomarkers with higher cancer volume and grade determined at the time of biopsy in an active surveillance cohort. Experimental Design: Urine was collected after digital rectal examination prospectively as part of the multi-institutional Canary Prostate Active Surveillance Study (PASS). PCA3 and TMPRSS2:ERG levels were analyzed in urine collected at study entry. Biomarker scores were correlated to clinical and pathologic variables. Results: In 387 men, both PCA3 and TMPRSS2:ERG scores were significantly associated with higher volume disease. For a negative repeat biopsy, and 1% to 10%, 11% to 33%, 34% or more positive cores, median PCA3, and TMPRSS2:ERG scores increased incrementally (P < 0.005). Both PCA3 and TMPRSS2:ERG scores were also significantly associated with the presence of high-grade disease. For a negative repeat biopsy, Gleason 6 and Gleason ≥7 cancers, the median PCA3, and TMPRSS2:ERG scores also increased incrementally (P = 0.02 and P = 0.001, respectively). Using the marker scores as continuous variables, the ORs for a biopsy in which cancer was detected versus a negative repeat biopsy (ref) on modeling was 1.41 (95% CI: 1.07–1.85), P = 0.01 for PCA3 and 1.28 (95% CI: 1.10–1.49), P = 0.001 for TMPRSS2:ERG. Conclusions: For men on active surveillance, both PCA3 and TMPRSS2:ERG seem to stratify the risk of having aggressive cancer as defined by tumor volume or Gleason score. Clin Cancer Res; 19(9); 2442–50. ©2013 AACR.

Can Urinary PCA3 Supplement PSA in the Early Detection of Prostate Cancer

PURPOSE Given the limited sensitivity and specificity of prostate-specific antigen (PSA), its widespread use as a screening tool has raised concerns for the overdiagnosis of low-risk and the underdiagnosis of high-grade prostate cancer. To improve early-detection biopsy decisions, the National Cancer Institute conducted a prospective validation trial to assess the diagnostic performance of the prostate cancer antigen 3 (PCA3) urinary assay for the detection of prostate cancer among men screened with PSA. PATIENTS AND METHODS In all, 859 men (mean age, 62 years) from 11 centers scheduled for a diagnostic prostate biopsy between December 2009 and June 2011 were enrolled. The primary outcomes were to assess whether PCA3 could improve the positive predictive value (PPV) for an initial biopsy (at a score > 60) and the negative predictive value (NPV) for a repeat biopsy (at a score < 20). RESULTS For the detection of any cancer, PPV was 80% (95% CI, 72% to 86%) in the initial biopsy group, and NPV was 88% (95% CI, 81% to 93%) in the repeat biopsy group. The addition of PCA3 to individual risk estimation models (which included age, race/ethnicity, prior biopsy, PSA, and digital rectal examination) improved the stratification of cancer and of high-grade cancer. CONCLUSION These data independently support the role of PCA3 in reducing the burden of prostate biopsies among men undergoing a repeat prostate biopsy. For biopsy-naive patients, a high PCA3 score (> 60) significantly increases the probability that an initial prostate biopsy will identify cancer.

Plasma Choline Metabolites and Colorectal Cancer Risk in the Women's Health Initiative Observational Study

Few studies have examined associations between plasma choline metabolites and risk of colorectal cancer. Therefore, we investigated associations between plasma biomarkers of choline metabolism [choline, betaine, dimethylglycine, and trimethylamine N-oxide (TMAO)] and colorectal cancer risk among postmenopausal women in a case-control study nested within the Womens Health Initiative Observational Study. We selected 835 matched case-control pairs, and cases were further stratified by tumor site (proximal, distal, or rectal) and stage (local/regional or metastatic). Colorectal cancer was assessed by self-report and confirmed by medical records over the mean of 5.2 years of follow-up. Baseline plasma choline metabolites were measured by LC/MS-MS. In multivariable-adjusted conditional logistic regression models, plasma choline tended to be positively associated with rectal cancer risk [OR (95% confidence interval, CI)(highest vs. lowest quartile) = 2.44 (0.93-6.40); P trend = 0.08], whereas plasma betaine was inversely associated with colorectal cancer overall [0.68 (0.47-0.99); P trend = 0.01] and with local/regional tumors [0.64 (0.42-0.99); P trend = 0.009]. Notably, the plasma betaine:choline ratio was inversely associated with colorectal cancer overall [0.56 (0.39-0.82); P trend = 0.004] as well as with proximal [0.66 (0.41-1.06); P trend = 0.049], rectal [0.27 (0.10-0.78); P trend = 0.02], and local/regional [0.50 (0.33-0.76); P trend = 0.001] tumors. Finally, plasma TMAO, an oxidative derivative of choline produced by intestinal bacteria, was positively associated with rectal cancer [3.38 (1.25-9.16); P trend = 0.02] and with overall colorectal cancer risk among women with lower (vs. higher) plasma vitamin B12 levels (P interaction = 0.003). Collectively, these data suggest that alterations in choline metabolism, which may arise early in disease development, may be associated with higher risk of colorectal cancer. The positive association between plasma TMAO and colorectal cancer risk is consistent with an involvement of the gut microbiome in colorectal cancer pathogenesis.

Biomarkers of inflammation are associated with colorectal cancer risk in women but are not suitable as early detection markers.

Initial studies have investigated the association between inflammation and colorectal cancer (CRC) using C‐reactive protein (CRP) as a proinflammatory biomarker and have noted inconsistent results among women. We here report the findings from a large prospective study with repeat measurements of CRP, as well as serum amyloid A (SAA), an additional biomarker of inflammation, and risk of CRC. In the Womens Health Initiative Observational Study, we examined associations of CRP and SAA with CRC using repeat assessments (baseline and 3‐year follow‐up) among 953 matched case–control pairs for CRP and 966 pairs for SAA. Multivariate‐adjusted conditional‐logistic regression models were used with two‐sided tests of significance. Receiver operating characteristic (ROC) curve analysis assessed their utility as early detection markers. Colon cancer risk (odds ratio [OR] and 95% confidence intervals) among women in the highest quintiles of CRP or SAA compared to those in the lowest quintiles was ORcolon/CRP = 1.37 (0.95–1.97, p‐trend = 0.04) and ORcolon/SAA = 1.26 (0.88–1.80, p‐trend = 0.10), respectively. Women with elevated concentrations of both CRP and SAA had an increased risk of ORcolon = 1.50 (1.12–2.00, p‐value = 0.006) compared to those with low concentrations. No positive associations were observed with rectal cancer and weaker associations for CRC overall. Temporal changes in biomarkers more than 3 years did not predict risk. The area under the 6‐month ROC curve for CRP+SAA was 0.62 (95% confidence interval = 0.55–0.68). Elevated inflammatory biomarkers are associated with an increased risk of CRC, mainly colon cancer. Nevertheless, changes in the biomarkers over time do not suggest that they merit consideration as early detection markers for CRC.

Homocysteine, cysteine, and risk of incident colorectal cancer in the Women's Health Initiative observational cohort

BACKGROUND Inflammation underlies the etiology of colorectal cancer (CRC). Hyperhomocysteinemia is associated with inflammation and may be a risk marker for CRC. Cysteine is a metabolic product of homocysteine and a precursor of the antioxidant glutathione. It is unknown whether cysteine is associated with CRC. OBJECTIVE The objective was to assess the associations between homocysteine and cysteine and CRC incidence in postmenopausal women. DESIGN Associations between homocysteine and cysteine and incident CRC in the Womens Health Initiative observational cohort were assessed by using a nested case-control design. Cases and controls (n = 988/group) were matched for age (mean ± SD age: 67 ± 7 y), ethnicity (85.2% white, 8.9% black, 2.2% Hispanic/Latina, and 3.6% other), hysterectomy status, and date of blood draw. Homocysteine and cysteine were measured by HPLC with postcolumn fluorimetric detection. RESULTS Multivariate-adjusted ORs (95% CIs) for CRC were 1.46 (1.05, 2.04) for the highest quartile of homocysteine (>9.85 μmol/L) compared with the lowest quartile (≤6.74 μmol/L) (P = 0.02) and 0.57 (0.40, 0.82) for the highest quartile of cysteine (>309 μmol/L) compared with the lowest quartile (≤260 μmol/L) (P = 0.01). The association with homocysteine was significant for proximal colon tumors (P = 0.008) but not for distal or rectal tumors, whereas the association with cysteine was significant for rectal tumors (P = 0.02), borderline for proximal tumors (P = 0.06), and not significant for distal tumors. The associations with both homocysteine and cysteine were significant for localized tumors (P ≤ 0.01) but not for metastases. CONCLUSION High plasma homocysteine is associated with increased risk of CRC, whereas high cysteine is associated with decreased risk. This trial was registered at clinicaltrials.gov as NCT 00000611.

Impact of folic acid fortification on global DNA methylation and one-carbon biomarkers in the Women's Health Initiative Observational Study cohort

DNA methylation is an epigenetic mechanism that regulates gene expression and can be modified by one-carbon nutrients. The objective of this study was to investigate the impact of folic acid (FA) fortification of the US food supply on leukocyte global DNA methylation and the relationship between DNA methylation, red blood cell (RBC) folate, and other one-carbon biomarkers among postmenopausal women enrolled in the Womens Health Initiative Observational Study. We selected 408 women from the highest and lowest tertiles of RBC folate distribution matching on age and timing of the baseline blood draw, which spanned the pre- (1994–1995), peri- (1996–1997), or post-fortification (1998) periods. Global DNA methylation was assessed by liquid chromatography-tandem mass spectrometry and expressed as a percentage of total cytosine. We observed an interaction (P = 0.02) between fortification period and RBC folate in relation to DNA methylation. Women with higher (vs. lower) RBC folate had higher mean DNA methylation (5.12 vs. 4.99%; P = 0.05) in the pre-fortification period, but lower (4.95 vs. 5.16%; P = 0.03) DNA methylation in the post-fortification period. We also observed significant correlations between one-carbon biomarkers and DNA methylation in the pre-fortification period, but not in the peri- or post-fortification period. The correlation between plasma homocysteine and DNA methylation was reversed from an inverse relationship during the pre-fortification period to a positive relationship during the post-fortification period. Our data suggest that (1) during FA fortification, higher RBC folate status is associated with a reduction in leukocyte global DNA methylation among postmenopausal women and; (2) the relationship between one-carbon biomarkers and global DNA methylation is dependent on folate availability.

Folate-mediated one-carbon metabolism genes and interactions with nutritional factors on colorectal cancer risk: Women's Health Initiative Observational Study

Investigations of folate‐mediated one‐carbon metabolism (FOCM) genes and gene‐nutrient interactions with respect to colorectal cancer (CRC) risk are limited to candidate polymorphisms and dietary folate. This study comprehensively investigated associations between genetic variants in FOCM and CRC risk and whether the FOCM nutrient status modified these associations.

Red blood cell folate and plasma folate are not associated with risk of incident colorectal cancer in the Women's Health Initiative observational study

The relationship between folate and colorectal cancer (CRC) risk is unclear. We investigated the association of two biomarkers of folate status, plasma folate and red blood cell (RBC) folate, with CRC risk using a nested case–control design in the Womens Health Initiative Observational Study. Postmenopausal women (n = 93,676) aged 50–79 years were enrolled in the Womens Health Initiative Observational Study (1993–1998). A fasting blood draw and extensive health, dietary and lifestyle data were collected upon enrollment. Through 2008, 988 incident CRC cases were reported and confirmed with medical records adjudication. Cases and controls were matched on age (±3 years), enrollment date (±1 year), race/ethnicity, blood draw date (±6 months) and hysterectomy status. Plasma and RBC folate were determined by radio assay. Folate biomarker values were divided into quartiles, and conditional logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CI) for the associations of folate with total CRC, by tumor site and by stage at diagnosis. Additional analyses examined whether risks varied across time periods corresponding to the United States folic acid fortification policy: prefortification (1994–1995), perifortification (1996–1997) and postfortification (1998). ORs for overall CRC risk comparing Q4 vs. Q1 were 0.91 (95% CI 0.67–1.24) and 0.91 (95% CI 0.67–1.23) for RBC and plasma folate, respectively. There were no changes in risk attributable to food supply fortification. These results do not support an overall association of folate with CRC risk and suggest that folic acid fortification of the US food supply did not alter the associations in these postmenopausal women.

Urinary TMPRSS2: Use of ERG and PCA3 to predict tumor volume and Gleason grade in an active surveillance cohort—Results from the Canary/EDRN Prostate Active Surveillance Study.

2 Background: Active surveillance is an increasing alternative for the management of low risk prostate cancer; however, there is a crucial need for better biomarkers to distinguish men with indolent versus aggressive disease. Both PCA3 and TMRPSS2-ERG (T2-ERG) are biomarkers that show promise in that they may be associated with more aggressive disease. This study examines the correlation of these biomarkers with higher volume or grade cancer in an active surveillance cohort. METHODS Post-DRE urine was collected prospectively as part of the multi-institutional Canary/EDRN Prostate Active Surveillance Study (PASS). PCA3 and T2-ERG levels were analyzed in urine collected from 401 men at study entry. Many of the men had undergone previous biopsies after initial prostate cancer diagnosis, and 20% of the urine specimens were associated with a negative serial biopsy. Biomarker scores were correlated to clinical and pathologic variables, including tumor volume - measured by percent of biopsy core involvement - and Gleason score, using non-parametric and univariate analyses. RESULTS Both PCA3 and T2-ERG scores were significantly associated with higher volume disease. For negative repeat biopsy, 1-10%, 11-34%, >34% positive cores, median (95% CI) PCA3 scores were 27 (24-31), 26 (22-33), 40 (29-51), 47 (26-90), p = 0.003 [Kruskal Wallis test (KW)], and median T2-ERG scores were 5 (2-8), 9 (4-14), 21 (14-40), 23 (4-115), p < 0.0001 (KW). Both PCA3 and T2-ERG scores were also significantly associated with presence of higher grade disease. For negative biopsy, Gleason 5 - 6, and Gleason >7, the median PCA3 scores were 27 (24-31), 31 (27-35), 48 (31-92), p = 0.02 (KW), and median T2-ERG scores were 5 (2-8), 14 (9-18), 29 (13-78), p = 0.001 (KW). The odds ratio for a positive biopsy versus a negative biopsy (ref) on modeling was 1.37 (1.04-1.81), p = 0.02 for PCA3 and 1.30 (1.12-1.51), p = 0.0006 for T2-ERG. CONCLUSIONS Both PCA3 and T2-ERG appear to stratify risk, for men on active surveillance, of having aggressive cancer as defined by tumor volume or Gleason score and may have clinical applicability in selecting men with low volume/low grade disease for active surveillance.

Folate-mediated one-carbon metabolism genes and interactions with nutritional factors on colorectal cancer risk

Investigations of folate‐mediated one‐carbon metabolism (FOCM) genes and gene‐nutrient interactions with respect to colorectal cancer (CRC) risk are limited to candidate polymorphisms and dietary folate. This study comprehensively investigated associations between genetic variants in FOCM and CRC risk and whether the FOCM nutrient status modified these associations.