Su1808 Exome Sequencing Detected Candidate Genes in Patients With Peutz-Jeghers Syndrome

mutation to determine loss of heterozygosity (LOH). When additional tumor tissue was available, p53 immunohistochemistry (IHC) was performed. Statistical analysis was performed with Fisher's exact test and ANOVA. Results: Normal and tumor tissue was available for 320 patients who underwent pancreatic resections for malignant or premalignant disease. 63 patients self-identified as AJ: 38 underwent surgery for PDAC, 7 for intraductal papillary mucinous neoplasm (IPMN), 18 for other disease. A high frequency of total BRCA1/2 mutations was found in the overall AJ cohort (10/63, or 15.87%, p<.001), in the AJ PDAC cohort (7/38, or 18.42%, p<.001), and in the AJ IPMN cohort (2/7 or 28.57%, p=.010) compared to published controls. High frequencies of all BRCA1 mutations (7.89%, p=.010), BRCA1 5382insC (2.63%, p=.139), BRCA1 185delAG (5.26%, p=.035) and BRCA2 6174delT (10.53%, p<.001) in AJ PDAC patients were demonstrated. BRCA1/2 LOH was found in 5 PDACs microdissected to date: 3/4 BRCA2 PDACs and 2/3 BRCA1 PDACs. Nuclear staining for p53 was found in 2/3 BRCA1/2 carriers with PDAC tested to date. Mean age at PDAC diagnosis was 60.7 years in BRCA1/2 carriers compared to 69.9 years in non-carriers (p= .031), but no differences in tumor histology were noted. Vital status was similar between groups (p=.408). Conclusions: We demonstrate a high frequency of both BRCA1 and BRCA2 mutations with LOH in an unselected cohort of surgically resected PDAC and preneoplastic lesions, suggesting these germline mutations are causal in select individuals carrying these mutations. Furthermore, nuclear p53 IHC suggests cooperation of p53 with BRCA1/2 in the causal pathway. BRCA1/2 carriers are diagnosed earlier with PDAC, which may suggest an opportunity for screening, although no other clinicopathologic differences were noted. Ongoing studies will further elucidate the carcinogenic pathway in these patients.

Su1808 Exome Sequencing Detected Candidate Genes in Patients With Peutz-Jeghers Syndrome Bayasi Guleng, Na-Na Xie, Jian-Lin Ren Peutz-Jeghers Syndrome (PJS) is an autosomal dominant disorder characterized by melanocytic macules of the lips, buccal mucosa, digits; multiple gastrointestinal hamartomatous polyps; and an increased risk of various neoplasms. To date, mutations in the serine/threonine kinase 11 (STK11) gene has been identified as a major cause of PJS, accounted for 40-60% of families with PJS and considered as genetic heterogeneity. We collected venous blood samples from three affected individuals ( father, son and daughter) and other three unaffected individuals in a three-generation Chinese family with PJS and obtain genomic DNA. We sequenced the whole exome of the three patients by the Illumina Hiseq 2000 instrument and reagents platform and aligned to the human hg19 reference genome (GRCh37/ UCSC hg19). Then SNP, insertions and deletions (indels) were identified by using public dates dbSNP132 and 1000 Genome Project (20100208 release). The whole exome sequence detected them share 10 mutation protein-code genes (TDG, STK11, DSPP, OR4C45, OR5D13, ZAN, APBB3, ODZ4, IL1F10, SPNS1) and 4 mutation pre-microRNAs (MI0003131, MI0003530, MI0014206, MI0005525). All variants of the protein-code genes, consisting of 7 INDEL and 3 SNP are predicted to have functional impact. Especially, the mutation of STK11 C.341-342T in exon 2, resulting in a frameshift (p.V114fs) was a novel and has never been previously described. And then Sanger sequencing was used to screen the variants of the three patients and three additional presumptive unaffected family members. All three affacted individuals were found to be heterozygous for these mutations and no clinically unaffected family members carried these variants. This study has expanded the genotypic spectrum of the STK11 gene, and further supported the hypothesis of genetic heterogeneity for PJS, and offered new candidate genes.

Su1811 The Risk of Non-Colorectal Malignancies in Serrated Polyposis Syndrome Patients and Their First-Degree Relatives Yark Hazewinkel, Johannes Reitsma, Jan J. Koornstra, Fokko Nagengast, Monique van Leerdam, Theo A. van Os, Hans F. Vasen, Evelien Dekker BACKGROUND Serrated polyposis syndrome (SPS) is characterized by the presence of multiple hyperplastic polyps (HPs) and sessile serrated adenomas (SSAs) spread throughout the colon and is associated with an increased colorectal cancer (CRC) risk. Although the underlying genetic causes of SPS are unknown, first degree relatives (FDRs) of SPS patients have an increased risk for both SPS and CRC suggesting an inheritable component. As in other polyposis syndromes an increased risk for extracolonic tumors has been described, the aim of this study was to assess the risk of malignancies other than CRC in both SPS patients and their FDRs. METHODS The medical history of SPS patients in 5 academic medical centers was retrospectively collected. Regarding the incidence of non-colorectal malignancies in FDRs, self-reported family history was derived from SPS patients by examining data from the department of Clinical Genetics. The incidence rates of non-colorectal malignancies in both SPS patients and their FDRs were compared with the general population through a person-year analysis, adjusted for age and sex. Population-based incidence data were derived from the Eindhoven Cancer Registry during the period 1989-2008. RESULTS A total of 105 SPS patients (57% male) and 341 FDRs from 53 pedigrees (50% male) were included, resulting in 6.423 and 18.935 person years of follow up, respectively. During follow up, 9 SPS patients (9%) developed a non-colorectal malignancy, which was not higher that the expected number of 13 (RR 0.69 95%-CI 0.36-1.33; p=0.27). In 44 FDRS (13%) a non-colorectal malignancy was detected, compared to 48 expected malignancies (RR 0.92 95%-CI 0.69-1.24; p=0.60). CONCLUSION Our results showed that the overall incidence of non-colorectal malignancies is not increased in SPS patients and their FDRs in comparison with the general population. Although we did not observe one dominant malignancy, future (international) multicenter studies with larger sample sizes are needed to compare the incidence of specific non-CRC malignancies in SPS patients with the general population.

Su1809 A Novel Complex Microsatellite in the Akr1b10 Promoter as a Marker for Differentiation and Lymphatic Metastasis of Colorectal Cancer Paulette A. Krishack, Stephen Markwell, Ruilan Yan, James Bonacum, Sara Robbins, John Gao, Mei C. Huang, Delaing Cao Disease-specific markers are critical for early diagnosis, targeted therapy, and prognosis of many potentially fatal diseases. The current study reports on a novel complex microsatellite as a marker for colorectal cancer. This microsatellite is located at -604 to -549 bp of aldoketo reductase family 1 member B10 (AKR1B10) promoter, composed of three 4-nucleotide tandem repeats, (TTCC)2(TCCC)5(TCCT)7. We analyzed the polymorphisms of this microsatellite in 45 colorectal cancer, 35 normal adjacent tissues (NAT), 21 inflammatory bowel disease (IBD), and 46 healthy donors. Our results showed that the overall polymorphic frequency was higher in colorectal cancer (71.1%) than in NAT (48.6%) (p=0.0401). Of the three tandem repeats, the (TCCT)7 site was the most unstable with alterations in 75.0 - 100% of polymorphic samples, compared to 30.8 - 46.2% at the (TTCC)2 site and 3.8 9.4% at the (TCCC)5 site (p=0.0001). Polymorphisms at the (TCCT)7 site were composed primarily of insertions with 1 to 4 copies of TCCT (83.3 - 95.8%) in which one-copy TCCT insertions were significantly lower in IBD tissues (7.7%) than in NAT (47.1%) (p=0.0417). Deletions were rare in this site, accounting for only 4.2 - 16.7% of the polymorphisms. The (TTCC)2 site was featured with one-copy TTCC insertions. Pair-wise analysis between colorectal tumor and NAT revealed that 10 of 16 (62.5%) cases with polymorphisms displayed further expansions, contractions, or both in the tumor samples. Cross-analysis with clinicopathological data of 32 colorectal cancer revealed that the polymorphic alterations of this microsatellite negatively correlated with tumor differentiation (p=0.0198) and local lymphatic metastasis (p=0.0330), suggesting the potential as a prognostic marker for the colorectal cancer.

Su1812 Advanced Colorectal Adenomas in Patients Under 45 Years of Age: Are We Still Missing Lynch Syndrome? Vladimir M. Kushnir, Jonathan Goodwin, Elyas Safar, Reena V. Chokshi, Nicholas O. Davidson, Riad R. Azar BACKGROUND: Lynch syndrome (LS) is the most common hereditary form of colorectal cancer (CRC), with mean age of CRC onset of 45. By contrast, <2% of the general population develops adenomas by age 40. While the development of advanced colorectal adenomas (ACA) in patients ≤45 is suggestive of LS, the degree to which clinicians recognize this and recommend genetic counseling is unclear. Furthermore, there is limited data on the natural history of ACA in patients ≤45 without confirmed LS. AIMS: 1)Evaluate the outcomes of patients ≤45 with ACA following polypectomy. 2)Determine the rate of referral for genetic counseling of potential LS. METHODS: Patients 18-45 yr with ACA (villous histology, high grade dysplasia, ≥1 cm in diameter, >2 polyps any size) diagnosed between 2001-11 were identified from the endoscopic database of a single medical center. Clinical, histological and follow up data were recorded. Patients with polyposis syndromes, inflammatory bowel disease, CRC, or <1 year of endoscopic follow up were excluded. Factors associated with adenoma recurrence and referral for genetic counseling were assessed. RESULTS: 76 [40.1% male, mean age (±SD) 40.6±5.4 yr] patients were identified with the following baseline demographics: 17(24.3%) first degree relative with CRC, 2(2.9%) personal history of cancer [lung 1, breast 1], 24(34.8%) smokers, 9(11.8%) diabetic, 22(28.9%) African American, mean body mass index 30.7±8.1. Indications for index colonoscopy were: gastrointestinal (GI) bleeding 39(51.3%), family history of CRC 17(22.4%), other GI symptoms 20(26.3%). Index colonoscopy revealed a median of 1 adenoma [range 1-4], mean diameter 12.9±7.1mm, 34.8% of polyps were right sided, 40(52.6%) had villous histology. All adenomas were endoscopically resected. The mean follow up duration was 3.3±2 years. Recurrent adenomas developed in 24(31.6%), of which 8(10.5%) were ACA; none of the patients developed CRC during follow up. The mean time to recurrence of ACA was 26.4±10.3 months. Adenoma recurrence was only associated with advancing age (p=0.03). 36(44.7%) patients met Bethesda criteria for LS, of whom 6(16.6%) were referred for genetic counseling; none of the polyps were sent for MSI/MMR testing. Patients referred for genetic counseling were younger (30.5yr, p<0.001) than those who were not (41.4yr). CONCLUSIONS: We

Su1810 Demonstration of a High Frequency of BRCA1 and BRCA2 Germline Mutations With Loss of Heterozygosity: A Series of Resected Pancreatic Adenocarcinomas and Other Preneoplastic Lesions Aimee L. Lucas, Reena Shakya, Marla Lipsyc, Elana B. Mitchel, Sheila Kumar, Caroline Hwang, Liyong Deng, Catherine DeVoe, Matthias Szabolcs, Thomas Ludwig, John A. Chabot, Wendy Chung, Harold Frucht Background: Pancreatic ductal adenocarcinoma (PDAC) is deadly and 10% are associated with a positive family history. Detection of precursor lesions in high-risk populations provides a unique opportunity for screening, prevention and cure of early PDAC. Select patient populations are at high risk for PDAC, including those with breast ovarian cancer syndrome (BRCA1/2) mutations. It is unknown if this association is causal. Methods: Institutional Review Board-approved cohort of patients who underwent surgical pancreatic resection at Columbia University. Clinical and demographic features were extracted from a de-identified database. Normal pancreatic DNA was extracted and genotyped for the three common Ashkenazi Jewish (AJ) BRCA1/2 founder mutations: BRCA1 5382insC, BRCA1 185delAG and BRCA2 6174delT. Tumor tissue from BRCA1/2 carriers was microdissected from surrounding stroma and DNA extracted. Tumor DNA was sequenced for the corresponding germline

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AGA Abstracts

AGA Abstracts

MSI-H without scoring. Scoring can be facilitated by a computerized evaluation form for routine CRC histology, prompting score computation & recommendation for MSI analysis with high specificity. This is being tried prospectively & includes: CRC patient age (<50yr), proximal site, well or poorly differentiated, mucinous differentiation, no dirty necrosis, >2 tumor-infiltrating lymphocytes/high-power field [4]. Usefulness of this simple method to supplement/compliment clinical identification of LS will be reassessed after a year. [1] Ladabaum U et al. Ann Intern Med 2011;155:69-79; [2] Schofield L et al, Int J Cancer 2009;124:1097-102. [3] Jenkins et al. Gastroenterology 2007;133:48-56; [4] Greenson et al. Am J Surg Pathol 2009;33:126-33