4121 Background: Resistance to anticancer drugs is a major obstacle preventing effective treatment of disseminated cancers. Understanding the molecular basis to chemoresistance is likely to provide better treatment. The aim of this work was to gain further understanding of the molecular mechanisms involved in oxaliplatin resistance in colorectal cancer (CRC) cells by using a proteomic approach and translate it to the clinical setting. Methods: An oxaliplatin resistant cell line (HTOXAR3) was established from human HT29 CRC cells. Proteins were extracted and analyzed through comparative proteomics. Results were confirmed by western blotting (WB) and Real Time Quantitative PCR. A tissue microarray constructed with 41 metastatic paraffin-embedded colorectal adenocarcinomas from patients treated with oxaliplatin + 5FU was used to determine p53, Ki-67 and bcl-2 expression. RNA from these tumors was subjected to RTQPCR to assess PKM2 mRNA expression. Differences in response were analyzed by contingency tables and chi-square test. Results: HTOXAR3 were 6 fold-resistant as compared to HT29 cells. Of the 47 spots >4 fold over-expressed or down-regulated in HTOXAR3 vs. HT29 cells, Mass Spectrometry, WB and RTQPCR confirmed down-regulation of PKM2 in HTOXAR3. In a panel of 8 CRC cell lines, we found a negative correlation between OXA resistance and PKM2 mRNA levels (spearman r = -0.846, p = 0.008). Oxaliplatin exposure in both HT29 and HTOXAR3 led to PKM2 mRNA up-regulation. Patients with the lowest PKM2 levels had lower response rates to oxaliplatin-based treatment (20% vs. 64.5% p =0.026) and overexpressed p53 (90% vs. 50%, p = 0.032). High PKM2 levels were associated with high ki-67 levels (p = 0.048). Conclusions: By using proteomics we have identified PKM2 as a putative predictive marker of response in CRC patients treated with oxaliplatin plus 5FU as first line chemotherapy. No significant financial relationships to disclose.

3750 Background: Colon cancer is the second neoplasm in men and women. Its prognostic depends on TNM staging at diagnosis. The treatment seems to improve the survival. The aim of this study is to analyze our series of surgical colon cancer from 1996 to 2001. Methods: We analyzed 422 surgical colon cancer. 70 patients were metastatic at the time of diagnosis or behind surgery (5 months). The remainder 352 patients without metastases were analyzed. The prognosis factors were: age at diagnosis, gender, locations in the large bowel, kind of surgery, pT, pN, stage, use of chemotherapy, disease free survival (DFS) and overall survival (OS). Results: The 352 non metastatic surgical colon cancer presented a mean age at diagnosis of 70,22 years (24 to 101). The ratio male/female was 197/155. The location in the bowel was: right 149 cases and left 203 cases. pT: pTis 6, pT114, pT2 43, pT3 244, pT4 41. pN: pN0 + pNX 229, pN1 70, pN2 52. 145 patients received adjuvant chemotherapy. Stage: I:49; II:171; III:122.pT: DFS was pT1=100%, pT2=93%, pT3=73%, pT4=51,2%. OS was pT1=71,4%, pT2=83,7%, pT3=66%, pT4=48,8%.pN: DFS was pN0=83,4%, pN1=64,3%,pN2=50%. OS was pN0=70,3%, pN1=61,4%, pN2=55,8%. Stage: OS was I=80%, II=68%, III=59%. Conclusions: The main prognostic factor for survival in colon cancer was the staging at diagnosis. Patients with pT4 or pN2 should received aggressive treatments for the high risk of metastasis. No significant financial relationships to disclose.

Human SMC2 is part of the condensin complex, which is responsible for tightly packaging replicated genomic DNA prior to segregation into daughter cells. Engagement of the WNT signaling pathway is known to have a mitogenic effect on cells, but relatively little is known about WNT interaction with mitotic structural organizer proteins. In this work, we described the novel transcriptional regulation of SMC2 protein by direct binding of the β-catenin·TCF4 transcription factor to the SMC2 promoter. Furthermore, we identified the precise region in the SMC2 promoter that is required for β-catenin-mediated promoter activation. Finally, we explored the functional significance of down-regulating SMC2 protein in vivo. Treatment of WNT-activated intestinal tumor cells with SMC2 siRNA significantly reduced cell proliferation in nude mice, compared with untreated controls (p = 0.02). Therefore, we propose that WNT signaling can directly activate SMC2 transcription as a key player in the mitotic cell division machinery. Furthermore, SMC2 represents a new target for oncological therapeutic intervention. Human SMC2 is part of the condensin complex, which is responsible for tightly packaging replicated genomic DNA prior to segregation into daughter cells. Engagement of the WNT signaling pathway is known to have a mitogenic effect on cells, but relatively little is known about WNT interaction with mitotic structural organizer proteins. In this work, we described the novel transcriptional regulation of SMC2 protein by direct binding of the β-catenin·TCF4 transcription factor to the SMC2 promoter. Furthermore, we identified the precise region in the SMC2 promoter that is required for β-catenin-mediated promoter activation. Finally, we explored the functional significance of down-regulating SMC2 protein in vivo. Treatment of WNT-activated intestinal tumor cells with SMC2 siRNA significantly reduced cell proliferation in nude mice, compared with untreated controls (p = 0.02). Therefore, we propose that WNT signaling can directly activate SMC2 transcription as a key player in the mitotic cell division machinery. Furthermore, SMC2 represents a new target for oncological therapeutic intervention.

UNLABELLED: Peptidyl arginine deiminases (PADI) are a family of enzymes that catalyze the poorly understood posttranslational modification converting arginine residues into citrullines. In this study, the role of PADIs in the pathogenesis of colorectal cancer was investigated. Specifically, RNA expression was analyzed and its association with survival in a cohort of 98 colorectal cancer patient specimens with matched adjacent mucosa and 50 controls from donors without cancer. Key results were validated in an independent collection of tumors with matched adjacent mucosa and by mining of a publicly available expression data set. Protein expression was analyzed by immunoblotting for cell lines or IHC for patient specimens that further included 24 cases of adenocarcinoma with adjacent dysplasia and 11 cases of active ulcerative colitis. The data indicate that PADI2 is the dominantly expressed PADI enzyme in colon mucosa and is upregulated during differentiation. PADI2 expression is low or absent in colorectal cancer. Frequently, this occurs already at the stage of low-grade dysplasia. Mucosal PADI2 expression is also low in ulcerative colitis. The expression level of PADI2 in tumor and adjacent mucosa correlates with differential survival: low levels associate with poor prognosis. IMPLICATIONS: Downregulation of PADI2 is an early event in the pathogenesis of colorectal cancer associated with poor prognosis and points toward a possible role of citrullination in modulating tumor cells and their microenvironment. Mol Cancer Res; 14(9); 841-8. ©2016 AACR.

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal disorder caused by mutations in DNA mismatch repair (MMR) genes. Tumors of the HNPCC-spectrum are associated with microsatellite instability (MSI) and loss of MMR protein expression. Lymphomas are not considered to be HNPCC-related tumors. We report and analyze a case of an HNPCC patient with three colorectal cancers and a B-cell non-Hodgkin lymphoma. Quantitative multiplex PCR of short fluorescent fragments detected a novel MSH2 rearrangement involving exons 9 and 10, which proved to be the pathogenic cause of the disease in the family. Tumor tissues including the lymphoma showed MSI and loss of MSH2 expression. Multiplex ligation-dependent probe amplification analysis revealed a somatic loss of the wild-type MSH2 allele in the lymphoma. These results support the fact that the total loss of a MMR gene can lead to lymphomagenesis, as seen in biallelic MMR-deficient families and knockout mice. Moreover, this is the first report of a B-cell non-Hodgkin lymphoma with a loss of the MSH2 protein expression, linked to a heterozygous germline MSH2 mutation in an HNPCC family.

BACKGROUND: Helicobacter pylori-associated peptic ulcer is a frequent complication in cirrhotic patients and its morbidity rate is high. In spite of this, diagnostic methods for H. pylori infection have not been fully evaluated in these patients. AIM: To evaluate H. pylori diagnostic methods in patients with liver cirrhosis. METHODS: One hundred and one cirrhotic patients were included in the study. Three antral and two corpus biopsies were obtained for rapid urease test of the antral mucosa, and Giemsa stain and immunohistochemistry were performed for both the corpus and antrum. Serology, 13C-urea breath test and faecal H. pylori antigen determination were also carried out. RESULTS: Sixty-two patients were positive and 35 were negative for H. pylori infection; four were indeterminate. The sensitivity and specificity were 90.4% and 100%, respectively, for antral histology, 100% and 100% for gastric body histology, 90.4% and 100% for antral immunohistochemistry, 96.2% and 96.7% for body immunochemistry, 85.7% and 97% for rapid urease test, 83.6% and 55.9% for serology, 96.4% and 97.1% for 13C-urea breath test and 75.4% and 94.1% for faecal antigen. CONCLUSION: The most reliable tests for H. pylori infection in cirrhotic patients were the 13C-urea breath test and gastric body histology.

BACKGROUND To assess the putative prognostic value of K-ras mutations in nonmucinous ovarian tumors, the authors looked for K-ras point mutations at codons 12 and 13 in 144 nonmucinous ovarian tumors. METHODS A series of 144 consecutive, unselected, archival, nonmucinous ovarian tumors (35 benign, 12 borderline, and 97 malignant) were studied. K-ras mutations at codons 12 and 13 were determined by polymerase chain reaction using the restriction fragment length polymorphism method with mismatched nested primers. Extensive clinicopathologic and follow-up data on all patients were evaluated. RESULTS The overall prevalence of K-ras mutations at codons 12 and 13 was 30.5% (44/144). In benign tumors, it was 20% (7/35); in borderline tumors, 25% (3/12); and in carcinomas, 35% (34/97). The presence of K-ras point mutations did not correlate with survival. Among the benign tumors, K-ras mutations were detected in three Brenner tumors with a mucinous component. CONCLUSIONS These results indicate that K-ras mutations are not initial events in the pathogenesis of nonmucinous ovarian tumors and do not appear to be related to survival. Cancer 1998;82:1088-95. © 1998 American Cancer Society.

PURPOSE: To evaluate proton fat-water chemical shift fast low-angle shot magnetic resonance (MR) imaging for differentiation of fat-containing hyperechoic liver nodules from hyperechoic liver nodules without a fatty component. MATERIALS AND METHODS: T1-weighted fast low-angle shot fat-water chemical shift gradient-echo MR imaging was performed in 96 patients without cirrhosis with 138 hyperechoic liver nodules. In-phase and opposed-phase breath-hold images were acquired. The percentage of signal intensity variation between in-phase and opposed-phase images and the spleen-to-lesion contrast ratio were used to differentiate liver nodules. RESULTS: Chemical shift MR images showed fat in 15 (11%) hyperechoic nodules (two angiomyolipomas and 13 nodular fatty infiltrations of the liver). The mean percentage of signal intensity variation between in-phase and opposed-phase images was 156% (standard error, 43.5%) in nodules with fat and -0.16% (standard error, 0.96%) in nodules without fat (P = .003). Spleen-to-lesion contrast was similar on in- and opposed-phase images in lesions without fat (mean difference, -0.0107; standard error, 0.012), whereas the mean difference in fat-containing nodules was 0.805 (standard error, 0.225; P = .003). The area under the receiver operating characteristic curve was 0.97 for signal intensity variation. CONCLUSION: Hyperechogenicity in certain liver nodules is caused by fat. Chemical shift MR imaging allows accurate differentiation between these and other hyperechoic lesions with no fat component.