Analysis of extended genomic rearrangements in oncological research.

Screening for genomic rearrangements is a fundamental task in the genetic diagnosis of many inherited disorders including cancer-predisposing syndromes. Several methods were developed for analysis of structural genomic abnormalities, some are targeted to the analysis of one or few specific loci, others are designed to scan the whole genome. Locus-specific methods are used when the candidate loci responsible for the specific pathological condition are known. Whole-genome methods are used to discover loci bearing structural abnormalities when the disease-associated locus is unknown. Three main approaches have been employed for the analysis of locus-specific structural changes. The first two are based on probe hybridization and include cytogenetics and DNA blotting. The third approach is based on PCR amplification and includes microsatellite or single nucleotide polymorphism (SNP) genotyping, relative allele quantitation, real-time quantitative PCR, long PCR and multiplex PCR-based methods such as multiplex ligation-dependent probe amplification and the recently developed nonfluorescent multiplex PCR coupled to high-performance liquid chromatography analysis. Whole-genome methods include cytogenetic methods, array-comparative genomic hybridization, SNP array and other sequence-based methods. The goal of the present review is to provide an overview of the main features and advantages and limitations of methods for the screening of structural genomic abnormalities relevant to oncological research

Gastric adenomas: relationship between clinicopathological findings, Helicobacter pylori infection, APC mutations and COX-2 expression.

Gastric adenomas are rare neoplastic growths characterized by localized polypoid proliferations of dysplastic epithelium that tend to progress to infiltrating adenocarcinoma. Therefore, the identification of molecular markers that could reliably recognize adenomas at risk of progression is advocated in the clinical management. In this study we investigated, in a series of gastric adenoma specimens from an area at high risk of gastric cancer, the relationship between clinicopathological characteristics of adenoma and Helicobacter pylori infection, APC mutational status, and COX-2 and the down-stream enzyme mPGES1 expression. Helicobacter pylori infection, detected in 24%, and 33% by histology and PCR analyses, respectively, did not show any relationship with growth pattern, localization, size, dysplasia grade and presence of synchronous cancer. Pathogenetic mutations of MCR region (codons 1269-1589) of the APC gene were detected only in one case corresponding to a single, small size, low grade, H. pylori-negative adenoma. The expression of COX-2 largely matched that of mPGES(1). Both were overexpressed in 79% of cases showing a relationship with high-grade dysplasia, size >10 mm and presence of a synchronous carcinoma. In conclusion, COX-2 may play a key role in the development and progression of gastric adenoma and could be an attractive target in the management of gastric adenoma at major risk of cancer development

Survival of hereditary non-polyposis colorectal cancer patients compared with sporadic colorectal cancer patients

<p>Abstract</p> <p>Background</p> <p>Patients with hereditary non-poliposys colorectal cancer (HNPCC) have better prognosis than sporadic colorectal cancer (CRC). Aim of our retrospective study was to compare the overall survival between sporadic CRC and HNPCC patients.</p> <p>Methods</p> <p>We analyzed a cohort of 40 (25 males and 15 females) HNPCC cases with a hospital consecutive series of 573 (312 males and 261 females) sporadic CRC observed during the period 1970–1993. In 15 HNPCC patients we performed mutational analysis for microsatellite instability. Survival rates were calculated by Kaplan-Meier method and compared with log rank test.</p> <p>Results</p> <p>The median age at diagnosis of the primary CRC was 46.8 years in the HNPCC series versus 61 years in sporadic CRC group. In HNPCC group 85% had a right cancer location, vs. 57% in the sporadic cancer group. In the sporadic cancer group 61.6% were early-stages cancer (Dukes' A and B) vs. 70% in the HNPCC group (p = ns). The crude 5-years cumulative survival after the primary CRC was 94.2% in HNPCC patients vs. 75.3% in sporadic cancer patients (p < 0.0001).</p> <p>Conclusion</p> <p>Our results show that overall survival of colorectal cancer in patients with HNPCC is better than sporadic CRC patients. The different outcome probably relates to the specific tumorigenesis involving DNA mismatch repair dysfunction.</p

Effect of oxidative stress on canonical/non-canonical WNT pathways in colon cancer cell lines

The importance of aberrant regulation of Wnt/β-Catenin signaling in the pathogenesis and colorectal cancer progression has long been recognised. Recent studies have shown that reactive oxygen species (ROS) production activates the Wnt/β-Catenin pathways, but the mechanisms involved remain unclear. Excess in ROS production is linked to chronic inflammation and promotes DNA damages and repair systems. We aim to evaluate the relationship among oxidative stress response and canonical/non-canonical Wnt pathways in colorectal cancer cell line models with different Wnt signaling behaviour

Evaluation of the canonical/non-canonical Wnt signalling pathways during oxidative stress in colorectal cancer cell line models

Background. The altered regulation of Wnt/β-Catenin pathways is linked with colorectal (CRC) carcinogenesis. Recent studies have shown that the Wnt/β-Catenin pathways are activated by reactive oxygen species (ROS) production, but the underlying molecular mechanisms are still unknown. Increased ROS are responsible for chronic inflammation, DNA lesions and repair systems. In order to evaluate the relationship among oxidative stress and canonical/non-canonical Wnt pathways, we studied the response to enhanced ROS in colorectal cancer cell lines with different Wnt signalling behaviour. Methods. HCT116 (MSI) and SW480 (MSS) cells were treated with H2O2 at different concentrations and times. Cell viability was determined by MTS and measured by the GloMax-Multi Detection System. Gene expression was evaluated by SYBR Green quantitative real-time PCR. Statistical analysis was performed by T-test (p value<0.05). Results. MTS showed different inhibition rates of cell proliferation at H2O2 concentrations. Acute stress was induced using H2O2 [2 mM and 10 mM] for 15’, 30’. H2O2 [2mM] treatment induced up-regulation of expression of canonical/non canonical molecules (LRP6 and LEF1; ROR2 and JUN/AP1) in SW480, and reduced expression of ROR2 and LRP6 co-receptors in HCT116. In SW480, at H2O2 [10mM], both ways showed a dose dependent increase. In HCT116, APC, LRP6, LEF1, P65-NFkB down-regulated gene expression was dependent on treatment time, in opposition to non-canonical ROR2 receptor. MUTYH, OGG1, NRF2, COX2 and JUN/AP1 showed significant increased expression. Conclusions. In MSI and MSS colon cancer cells, oxidative stress differently affects the WNT pathways. Our results could devise a new scenario for CRC therapeutic approaches