Foster, Nathan R.

Abstract Background. Autophagy maintains energy metabolism and enables tumor cell survival during cellular stress. Beclin 1 is involved in autophagosome formation during which membrane-bound LC3 binds to p62/sequestosome 1. We reported that ectopic p62 can promote 5-fluorouracil-induced cell death (JBC 286:40002-12, 2011). It is unknown whether these autophagy markers can predict clinical outcome. Materials & Methods. Beclin 1, LC3B, and p62 proteins were analyzed by immunohistochemistry in tissue microarrays containing stage II and III colon carcinomas (N=151) from patients receiving 5-FU or surgery alone. The mean weighted score (intensity x extent) was dichotomized for survival analysis using Cox models. Results. Increased levels of cytoplasmic LC3, Beclin 1, and p62 expression were detected in 21%, 14%, and 68% of cancers, respectively, and were not associated with tumor site, stage or grade. By multivariable analysis, increased LC3 was significantly associated with worse disease-free survival (DFS) (p=0.022), but not overall survival (OS) [p=0.069](Table). Beclin 1 was not prognostic, but increased p62 was significantly associated with improved DFS (p=0.038), but not OS (p= 0.176)[Table]. When restricted to 5-FU-treated patients, increased LC3 was associated with worse DFS [HR= 2.38 (1.19, 4.75, p=0.020), elevated Beclin 1 predicted worse OS [HR=2.83 (1.27, 6.34), p = 0.019], and p62 was not prognostic. Conclusion. LC3 and Beclin 1 overexpression were independently associated with adverse outcome. Increased p62 was associated with better outcome consistent with its ability to promote cell death. These data support strategies to inhibit autophagy for therapeutic advantage. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4112. doi:1538-7445.AM2012-4112

Abstract Background and Aims: In patients with Barrett's esophagus (BE), reflux-induced injury promotes esophageal adenocarcinoma, presumably through cyclooxygenase 2 (COX-2) related pathways. Proton pump inhibitors (PPIs) and nonsteroidal anti-inflammatory drugs (NSAIDs) may interrupt reflux-associated carcinogenesis by reducing acid exposure and subsequent inflammation. However, clinical trial data regarding the chemopreventive efficacy of a PPI + NSAID combination are limited. The aim of this multi-center, randomized, phase II trial was to assess the effects of a 28-day intervention with esomeprazole 40 mg bid and aspirin 81 mg qd, 325 mg qd, or placebo qd on tissue prostaglandin E2 (PGE2) concentrations in BE patients. Methods: Using the infrastructure of the Cancer Prevention Network, participants (> 18 years) with histologically confirmed non dysplastic BE were randomly assigned to receive one of three interventions for 28 days: (arm A) esomeprazole 40 mg bid+ aspirin 81 mg placebo qd + aspirin 325 mg placebo qd (n=42); (arm B) esomeprazole 40 mg bid+ aspirin 81 mg qd + aspirin placebo 325 qd (n=63); (arm C) esomeprazole 40 mg bid + aspirin 81 mg qd placebo + aspirin 325 mg qd (n=63). Esophageal biopsies were obtained pre- and post-intervention to assess change in PGE2 concentration as the primary endpoint. Results: In total, 122 participants were randomized, 121 (99%) completed the trial per protocol, and 115 (94%) were evaluated for the primary endpoint. Baseline characteristics were similar across intervention arms. The absolute change (mean + SD) in tissue PGE2 concentration was −67.6 (229.68) in Arm A, −120.9 (281.28) in Arm B (p = 0.10 vs Arm A) and −174.9 (263.62) in Arm C (p = 0.02 vs Arm A). Conclusions: In combination with esomeprazole 40 mg twice per day, aspirin 325 mg per day significantly reduced tissue PGE2 concentration in BE patients after a 28-day intervention, as compared to aspirin placebo. Given the relevance of PGE2 pathways in BE-associated carcinogenesis, further evaluation of this chemoprevention strategy in larger, more definitive phase III trials is warranted. Citation Information: Cancer Prev Res 2011;4(10 Suppl):CN06-03.

Abstract Purpose: Obesity is associated with an increased risk of colon cancer. However, the influence of body mass index (BMI) upon the outcome of colon cancer survivors and its relationship to gender remains unknown. Experimental Design: BMI (kg/m2) was calculated and categorized in patients with TNM stage II and III colon carcinomas (n= 4,381) enrolled in 7 randomized trials of 5-fluorouracil-based adjuvant chemotherapy. Cox proportional hazards modeling was used to determine the association of BMI with disease-free and overall survival. Results: Among colon cancer patients, 868 (20%) were obese (BMI ≥30 kg/m2) of which 606 were class 1 (BMI 30–34 kg/m2) and 262 were class 2,3 (BMI ≥35 kg/m2). Obese versus normal-weight patients were more likely to be younger, have distal tumors, show intact DNA mismatch repair (MMR), and have increased lymph node metastases (p <0.017). The association of BMI and MMR status was dependent upon patient age (p= 0.031). In a multivariate analysis, BMI was significantly associated with both disease-free (p=0.030) and overall survival (p=0.0017). Men with class 2,3 obesity showed reduced overall survival compared to normal weight men [HR 1.35 (1.02, 1.79); p=0.039]. Women with class I obesity had reduced overall survival [HR 1.24 (1.01, 1.53), p=0.045] compared to normal weight women. BMI was not predictive of therapeutic benefit. Conclusions: Obesity is associated with intact DNA mismatch repair status and was an adverse, independent prognostic variable in colon cancer survivors. Interventions to reduce obesity have the potential to improve patient outcomes in colon cancer survivors. Citation Information: Cancer Prev Res 2010;3(1 Suppl):B111.

PurposeAlthough the importance of obesity in colon cancer risk and outcome is recognized, the association of body mass index (BMI) with DNA mismatch repair (MMR) status is unknown.Patients and MethodsBMI (kg/m2) was determined in patients with TNM stage II or III colon carcinomas (n = 2,693) who participated in randomized trials of adjuvant chemotherapy. The association of BMI with MMR status and survival was analyzed by logistic regression and Cox models, respectively.ResultsOverall, 427 (16%) tumors showed deficient MMR (dMMR), and 630 patients (23%) were obese (BMI ≥ 30 kg/m2). Obesity was significantly associated with younger age (P = .021), distal tumor site (P = .012), and a lower rate of dMMR tumors (10% v 17%; P < .001) compared with normal weight. Obesity remained associated with lower rates of dMMR (odds ratio, 0.57; 95% CI, 0.41 to 0.79; P < .001) after adjusting for tumor site, stage, sex, and age. Among obese patients, rates of dMMR were lower in men compared with women (8% v 13%; P = .041). Obesity was associated with higher recurrence rates (P = .0034) and independently predicted worse disease-free survival (DFS; hazard ratio [HR], 1.37; 95% CI, 1.14 to 1.64; P = .0010) and overall survival (OS), whereas dMMR predicted better DFS (HR, 0.59; 95% CI, 0.47 to 0.74; P < .001) and OS. The favorable prognosis of dMMR was maintained in obese patients.ConclusionColon cancers from obese patients are less likely to show dMMR, suggesting obesity-related differences in the pathogenesis of colon cancer. Although obesity was independently associated with adverse outcome, the favorable prognostic impact of dMMR was maintained among obese patients.

Abstract Purpose: Obesity is associated with an increased risk of colon cancer. However, the influence of body mass index (BMI) upon the prognosis of colon cancer survivors and its relationship to gender remains unknown. Experimental Design: BMI (kg/m2) was categorized in patients with TNM stage II and III colon carcinomas (n= 4,381) enrolled in 7 randomized trials of 5-fluorouracil-based adjuvant chemotherapy. Cox proportional hazards models were used to determine the association of BMI with disease-free (DFS) and overall survival (OS). Results: Among colon cancer patients, 868 (20%) were obese (BMI &gt;30 kg/m2) of which 606 were class 1 (BMI 30-34 kg/m2) and 262 were class 2,3 (BMI &gt;35 kg/m2). Obese versus normal-weight patients were more likely to be younger (p=0.038), have distal tumors (0.058), show intact DNA mismatch repair (MMR) (p=0.035), and have more lymph node metastases (p=0.017). In a multivariate analysis, BMI was significantly associated with both DFS (p=0.030) and OS (p=0.0017). Men with class 2,3 obesity showed reduced OS compared to normal weight men [HR 1.35 (1.02, 1.79); p=0.039]. Women with class I obesity had reduced OS [HR 1.24 (1.01, 1.53), p=0.045] compared to normal weight women. Overweight status was associated with improved OS in men (p= 0.006) and underweight women had significantly worse OS (p= 0.019). BMI was not predictive of therapeutic benefit. Conclusions: Obesity is an independent prognostic variable in colon cancer survivors and shows gender-related differences. These data suggest that obesity-related biological factors can influence clinical outcome. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 904.

Purpose Prior reports have indicated that patients with colon cancer who demonstrate high-level microsatellite instability (MSI-H) or defective DNA mismatch repair (dMMR) have improved survival and receive no benefit from fluorouracil (FU) -based adjuvant therapy compared with patients who have microsatellite-stable or proficient mismatch repair (pMMR) tumors. We examined MMR status as a predictor of adjuvant therapy benefit in patients with stages II and III colon cancer. Methods MSI assay or immunohistochemistry for MMR proteins were performed on 457 patients who were previously randomly assigned to FU-based therapy (either FU + levamisole or FU + leucovorin; n = 229) versus no postsurgical treatment (n = 228). Data were subsequently pooled with data from a previous analysis. The primary end point was disease-free survival (DFS). Results Overall, 70 (15%) of 457 patients exhibited dMMR. Adjuvant therapy significantly improved DFS (hazard ratio [HR], 0.67; 95% CI, 0.48 to 0.93; P = .02) in patients with pMMR tumors. Patients with dMMR tumors receiving FU had no improvement in DFS (HR, 1.10; 95% CI, 0.42 to 2.91; P = .85) compared with those randomly assigned to surgery alone. In the pooled data set of 1,027 patients (n = 165 with dMMR), these findings were maintained; in patients with stage II disease and with dMMR tumors, treatment was associated with reduced overall survival (HR, 2.95; 95% CI, 1.02 to 8.54; P = .04). Conclusion Patient stratification by MMR status may provide a more tailored approach to colon cancer adjuvant therapy. These data support MMR status assessment for patients being considered for FU therapy alone and consideration of MMR status in treatment decision making.

AbstractPurpose: Obesity is associated with an increased risk of colon cancer. However, the influence of body mass index (BMI) on the prognosis of colon cancer survivors and its relationship to gender remains unknown.Experimental Design: BMI (kg/m2) was categorized in patients with tumor-node-metastasis stage II and III colon carcinomas (n = 4,381) enrolled in seven randomized trials of 5-fluorouracil–based adjuvant chemotherapy. Cox proportional hazards models were used to determine the association of BMI with disease-free survival (DFS) and overall survival (OS).Results: Among colon cancer patients, 868 (20%) were obese (BMI, ≥30 kg/m2), of which 606 were class 1 (BMI, 30-34 kg/m2) and 262 were class 2,3 (BMI, ≥35 kg/m2). Obese versus normal-weight patients were more likely to be younger, have distal tumors, show intact DNA mismatch repair, and have more lymph node metastases (P &lt; 0.017). In a multivariate analysis, BMI was significantly associated with both DFS (P = 0.030) and OS (P = 0.0017). Men with class 2,3 obesity showed reduced OS compared with normal-weight men [hazard ratio, 1.35; 95% confidence interval, 1.02-1.79; P = 0.039]. Women with class I obesity had reduced OS [hazard ratio, 1.24; 95% confidence interval, 1.01-1.53; P = 0.045] compared with normal-weight women. Overweight status was associated with improved OS in men (P = 0.006), and underweight women had significantly worse OS (P = 0.019). BMI was not predictive of therapeutic benefit.Conclusions: Obesity is an independent prognostic variable in colon cancer survivors and shows gender-related differences. These data suggest that obesity-related biological factors can influence clinical outcome. Clin Cancer Res; 16(6); 1884–93

Purpose To improve the understanding of the appropriate design of phase II oncology clinical trials, we compared error rates in single-arm, historically controlled and randomized, concurrently controlled designs. Patients and Methods We simulated error rates of both designs separately from individual patient data from a large colorectal cancer phase III trials and statistical models, which take into account random and systematic variation in historical control data. Results In single-arm trials, false-positive error rates (type I error) were 2 to 4 times those projected when modest drift or patient selection effects (eg, 5% absolute shift in control response rate) were included in statistical models. The power of single-arm designs simulated using actual data was highly sensitive to the fraction of patients from treatment centers with high versus low patient volumes, the presence of patient selection effects or temporal drift in response rates, and random small-sample variation in historical controls. Increasing sample size did not correct the over optimism of single-arm studies. Randomized two-arm design conformed to planned error rates. Conclusion Variability in historical control success rates, outcome drifts in patient populations over time, and/or patient selection effects can result in inaccurate false-positive and false-negative error rates in single-arm designs, but leave performance of the randomized two-arm design largely unaffected at the cost of 2 to 4 times the sample size compared with single-arm designs. Given a large enough patient pool, the randomized phase II designs provide a more accurate decision for screening agents before phase III testing.

Abstract Multiple genome-wide association studies have identified several susceptibility variants for colon cancer at 8q24. However, the functional roles of these variants have yet to be elucidated. Here, we evaluated the potential role of these markers in tumor progression and examined association with commonly observed structural abnormalities in this region, c-MYC amplification and chromosome fragility at FRA8C and FRA8D. We first replicated the previously reported association by testing 1,178 cases and 1,009 clinic-based controls with eight markers localized to three specific regions at 8q24. We observed significant associations with colon cancer risk with markers rs13254738 (ordinal odds ratio, 0.82; 95% confidence interval, 0.072-0.94; Ptrend = 0.0037) and rs6983267 (ordinal odds ratio, 1.17; 95% confidence interval, 1.03-1.32, Ptrend = 0.013). Survival analysis was done using a separate set of 460 cases to evaluate the clinical significance of these markers. Overall, univariate analysis did not detect survival differences for any of the markers. We also tested a subset of the 460 cases (n = 380) for structural abnormalities at or near the c-MYC locus using fluorescence in situ hybridization analysis. Furthermore, we evaluated a small number of cases homozygous for the rs6983267 alleles to test for differences in fragile site induction. None of the 8q markers correlated with amplification at the c-MYC locus as detected by fluorescence in situ hybridization, and no clear pattern of breakage was observed at the FRA8C and FRA8D sites. In this study, we confirm the association for several single nucleotide polymorphisms at 8q24 in colon cancer but have not detected any structural role relating to c-MYC amplification or chromosomal fragility. Finally, these risk alleles do not seem to be associated with survival. (Cancer Epidemiol Biomarkers Prev 2009;18(9):2492–500)

Abstract Purpose: Proapoptotic BH3-only proteins (Bim, Bad, Bid, Puma, and Noxa) initiate apoptosis by binding to regulatory sites on antiapoptotic Bcl-2 proteins, directly neutralizing their cytoprotective function. Expression of these proteins in colon cancer patients may account for differences in recurrence and survival rates. Experimental Design: Archival tumor-node-metastasis stage II and III primary colon carcinomas from patients treated in 5-fluorouracil–based adjuvant therapy trials were studied. Immunohistochemical analysis of Bim, Puma, and Noxa proteins was done using tissue microarrays (n = 431). Immunoscores were determined and correlated with clinicopathologic variables and disease-free survival (DFS) and overall survival (OS) rates. Results: Elevated expression of proapoptotic Bim (hazard ratio, 0.65; 95% confidence interval, 0.44-0.97; P = 0.033) and Puma (hazard ratio, 0.59; 95% confidence interval, 0.37-0.93; P = 0.022), but not Noxa, proteins in the tumor cytoplasm was significantly associated with more favorable OS in a univariate analysis, and elevated Bim expression was also associated with better DFS (P = 0.023). Patient age, tumor stage, and histologic grade were also prognostic. Multivariate Cox analysis showed that Bim (DFS, P = 0.030; OS, P = 0.045) and Puma (OS, P = 0.037) expression were independent predictors of OS after adjustment for histologic grade, tumor stage, age, and treatment. Furthermore, the combined variable of Bim and Puma was highly discriminant for both DFS (P = 0.0034) and OS (P = 0.0011). Conclusions: The proapoptotic BH3-only proteins Bim and Puma can provide prognostic information for stage II and III colon cancer patients receiving 5-fluorouracil–based adjuvant chemotherapy. Furthermore, our results support BH3-only proteins as molecular targets of novel anticancer drugs.