Shuber, Anthony P.

Background and Aims: The benefit of adjuvant chemotherapy for stage II colorectal cancer (CRC) patients remains unclear, emphasizing the need for improved prognostic biomarkers to identify patients at risk of metastatic recurrence. To address this unmet clinical need, we examined the expression and phosphorylation status of the vasodilator-stimulated phosphoprotein (VASP) in CRC tumor progression. VASP, a processive actin polymerase, promotes the formation of invasive membrane structures leading to extracellular matrix remodeling and tumor invasion. Phosphorylation of VASP serine (Ser) residues 157 and 239 regulate VASP function, directing subcellular localization and inhibiting actin polymerization, respectively. Methods: The expression levels of VASP protein, pSer157-VASP, and pSer239-VASP were determined by immunohistochemistry in tumors and matched normal adjacent tissue from 141 CRC patients, divided into 2 cohorts, and the association of VASP biomarker expression with clinicopathologic features and disease recurrence was examined. Results: We report that changes in VASP expression and phosphorylation were significantly associated with tumor invasion and disease recurrence. Furthermore, we disclose a novel 2-tiered methodology to maximize VASP positive and negative predictive value performance for prognostication. Conclusion: VASP biomarkers may serve as prognostic biomarkers in CRC and should be evaluated in a larger clinical study.

Abstract Introduction The presence of blood in the urine (hematuria) is one of the hallmark symptoms of bladder cancer. Thus, the current best practice policy suggests that patients with hematuria undergo cystoscopic examination. However, hematuria can be present in healthy individuals as well as in individuals with various non-life threatening conditions such that a majority of patients with blood in the urine (∼95%) who are screened by cystoscopy do not have bladder cancer. In addition, recent studies have found that a majority of patients with hematuria are not referred on to a specialist for further invasive tests, despite the guidelines. This suggests that the prevalence of cancer in this population may be lower than 5%, making screening by cystoscopy inefficient and, in a large number of cases, unnecessary. We are developing a non-invasive diagnostic assay utilizing urinary protein and DNA biomarkers to triage those patients who do not have cancer from those who should go on to be existing invasive screening modalities. Methods Urine samples were obtained from 48 cancer patients and 256 patients who were evaluated for hematuria but who did not have cancer upon cystoscopic evaluation (Hem+/Cysto−). Twist1 and Nid2 methylation status was assessed using methylation-specific PCR primers and FGFR3 mutational status was determined by quantitative PCR. Matrix Metalloproteinases (MMPs) levels were determined by ELISA. Results Using a novel combination of these DNA and protein markers we identified with high confidence (99% negative predictive value) those patients who do not have cancer and who could be excluded from further testing. Cutoffs could be adjusted such that at 94% sensitivity, 65% of patients who do not have cancer could be excluded. Conclusions The Multi-Analyte Diagnostic Readout (MADR) assay described here combines the best performance characteristics of protein and DNA biomarkers into one assay for optimal clinical performance. Using this approach, the detection of FGFR3 mutations and Twist1 and Nid2 methylation in the urine of hematuria patients undergoing screening for bladder cancer effectively increases the sensitivity and negative predictive value at an established MMP protein cutoff. This non-invasive urinary diagnostic assay could lead to the more efficient triage of hematuria patients by identifying those patients who do not have cancer and could be excluded from receiving invasive procedures. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-313. doi:10.1158/1538-7445.AM2011-LB-313

Abstract Background: The genetic heterogeneity of sporadic colorectal cancer (CRC) makes the choice of genetic markers and sequence variation–detection technologies critical to the performance of screening assays. We have previously described the effectiveness of a CRC assay composed of 22 known variants in KRAS, APC, TP53, and BAT-26 (V1). We introduce a new marker formulation (V2) that includes detection of de novo variation in APC, PIK3CA, and CTNNB1, hypermethylated sequences within SMARCA3 and VIM, and a single-base variation within BRAF. We compared the abilities of the V1 and V2 markers to detect aberrant DNA in colorectal neoplasias. Methods: V1 and V2 marker formulations were used to analyze 144 colorectal tissue samples comprising 50 precancerous adenomas, 94 carcinomas, and 11 nonpathologic tissues. V1 analysis consisted of single-base extension analysis of the 22 V1 variants. V2 analysis consisted of DNA scanning of the APC mutation cluster region, PIK3CA exons 9 and 20, CTNNB1 exon 3, analysis for the BRAF Val600Glu substitution, and methylation-specific PCR analysis of VIM and SMARCA3. Results: The V2 marker formulation had significantly higher sensitivity than the V1 markers for carcinomas (93.6% and 72.3%, respectively; P = 0.0002) and adenomas (92.0% and 62.0%, respectively; P = 0.0006). None of the nonpathologic samples were positive for any marker. Conclusions: We demonstrate improved sensitivity of a new marker formulation (V2) to detect aberrant DNA in CRC and precancerous adenoma tumor tissues.

AbstractBackground: Molecular genetic analysis of DNA in patient stools has been proposed for screening of colorectal cancer (CRC). Because nonapoptotic cells shed from tumors may contain DNA that is less degraded than DNA fragments from healthy colonic mucosa, our aim was to show that DNA fragments isolated from stools of patients with CRC had higher integrity than DNA isolated from stools of patients with healthy colonic mucosa.Methods: We purified DNA from the stools of a colonoscopy-negative control group and patients with CRC and examined the relationship between long DNA fragments and clinical status by determining stool DNA integrity, using oligonucleotide-based hybrid captures with specific target sequences in increasingly long PCR reactions (200 bp, 400 bp, 800 bp, 1.3 kb, 1.8 kb, 24 kb). DNA fragments obtained from CRC patients were compared with fragments obtained from colonoscopy-negative individuals for length and/or integrity.Results: DNA fragments isolated from CRC patients were of higher molecular weight (>18 bands detected of a total of 24 possible bands) than fragments isolated from fecal DNA of the colonoscopy-negative control group.Conclusions: The presence of long DNA fragments in stool is associated with CRC and may be related to disease-associated differences in the regulation of proliferation and apoptosis. An assay of fecal DNA integrity may be a useful biomarker for the detection of CRC.