Sporadic colorectal cancer (CRC) is a consequence of the accumulation of genetic and epigenetic alterations that result in the transformation of normal colonic epithelial cells to adenocarcinomas. Studies have indicated that a common event in the tumorigenesis of CRC is the association of global hypomethylation with discrete hypermethylation at the promoter regions of specific genes that are involved in cell cycle regulation, DNA repair, apoptosis, angiogenesis, adhesion and invasion. The present study aimed to investigate the epigenetic changes (DNA methylation) in 24 candidate genes in CRC. A total of 10 candidate hypermethylated (HM) and unmethylated (UM) genes were identified that may be useful epigenetic markers for non-invasive CRC screening. The five genes that had the highest average UM percentages in the control group were MLH1 (71.7%), DKK2 (69.6%), CDKN2A (68.4%), APC (67.5%) and hsa-mir-342 (67.4%). RUNX3 (58.9%), PCDH10 (55.5%), SFRP5 (52.1%), IGF2 (50.4%) and Hnf1b (50.0%) were the five genes with the highest average HM percentages in the test group. In summary, the present preliminary study identified the methylation profiles of normal and cancerous colonic epithelial tissues, and provided the groundwork for future large-scale methylation studies.

Dietary habits, lifestyle, and polymorphisms in VDR (ApaI), CYP24A1 (rs6013897, rs158552, rs17217119) and CYP27B1 (rs10877012) were associated with a higher risk of CRC.

ABSTRACT.We investigated a possible association between alcoholism, cigarette smoking, obesity and CYP2E1 RsaI and 96-bp insertion genetic polymorphisms with risk for colorectal cancer (CRC). Patients with CRC (70 women and 61 men) were matched for gender and age to 206 healthy controls. The mean age of the two groups was 62 years. Meat intake, cigarette smoking and alcohol drinking were assessed using a specific frequency questionnaire. The body mass index was also calculated. DNA was extracted from peripheral blood; RsaI polymorphism genotypes were evaluated by PCR-RFLP and 96-bp insertion genetic polymorphisms were evaluated by specific primers. The distributions of CYP2E1 RsaI c1/c1, c1/c2 and c2/c2 genotypes were 90.2, 9.2 and 0.6%, respectively, in controls and 83.9, 13.7 and 2.4% in CRC cases. Allele c2 was associated with increased risk for CRC [odds ratio (OR) = 1.88, 95% confidence interval (95%CI) = 1.02-3.45]. The CYP2E1 RsaI c2/c2 genotype was associated with an increased risk for rectal cancer (OR = 3.23, 95%CI = 1.26-9.03). The 96-bp insertion was slightly more frequent in the CRC group (9.3 vs 11.4%, P = 0.19), especially in females (6.4 vs 11.5%, P = 0.34). Smoking, alcohol drinking or high intake of red meat and CYP2E1 polymorphisms were 3139 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 11 (3): 3138-3145 (2012) CYP2E1 RsaI c2/c2 genotype associated with CRC not associated with increased risk for CRC. The 96-bp insertion was marginally more frequent (P = 0.07) in undernourished CRC subjects. We concluded that the risk for CRC is higher among individuals with allele c2. The CYP2E1 RsaI c2/c2 genotype was associated with an increased risk for rectal cancer.

Gastric cancer (GC) is one of the most common malignancies worldwide. The ABCB1 protein, a member of the ATP-binding cassette (ABC) transporter family, encoded by the ABCB1 gene, considerably influences the distribution of drugs across cell membranes as well as multidrug resistance (MDR) of antineoplastic drugs. In contrast to the extensive knowledge on the pharmacological action of ABCB1 protein, the correlation between the clinical-pathological data and ABCB1 protein expression in patients with GC remains unclear. The aim was to investigate association between ABCB1 expression and overall survival in GC patients. Human tumor fragments from 57 GC patients were examined by immunohistochemistry assay. We observed lower survival rate of patients with GC who were positive for ABCB1 expression (p=0.030). Based on these observations, we conclude that GC patients with positive ABCB1 protein immunohistochemical expression in their tumors suffer shorter overall survival.

BACKGROUND: Colorectal cancer (CRC) is one of the leading causes of cancer worldwide. Early diagnostic methods using serum biomarkers are required. The study of omics, most recently lipidomics, has the purpose of analyzing lipids for a better understanding of human lipidoma. The evolution of mass spectrometry methods, such as MALDI-MS technology, has enabled the detection and identification of a wide variety of lipids with great potential to open new avenues for predictive and preventive medicine. OBJECTIVE: To determine the lipid profile of patients with colorectal cancer and polyps. METHODS: Patients with stage I-III CRC, adenomatous polyps and individuals with normal colonoscopy were selected. All patients underwent peripheral blood collection for lipid extraction. The samples were analyzed by MALDI-MS technique for lipid identification. STATISTICAL ANALYSIS: Univariate and multivariate (principal component analysis [PCA] and discriminant analysis by partial least squares [PLS-DA]) analyses workflows were applied to the dataset, using MetaboAnalyst 3.0 software. The ions were identified according to the class of lipids using the online database Lipid Maps (http://www.lipidmaps.org). RESULTS: We included 88 individuals, 40 with CRC, 12 with polyps and 32 controls. Boxplot analysis showed eight VIP ions in the three groups. Differences were observed between the cancer and control groups, as well as between cancer and polyp, but not between polyps and control. The polyketide (810.1) was the lipid represented in cancer and overrepresented in polyp and control. Among the patients with CRC we observed differences between lipids with lymph node invasion (N1-2) compared to those without lymph node invasion (N). CONCLUSION: Possible lipid biomarkers were identified among cancer patients compared to control and polyp groups. The polyketide lipid (810.1) was the best biomarker to differentiate the cancer group from control and polyp. We found no difference between the biomarkers in the polyp group in relation to the control.

Multidrug resistance (MDR) is a major impediment to successful chemotherapy of gastric cancer. Our aim was to establish an epirubicin-resistant cell subline (AGS/EPI) and to elucidate the mechanisms involved in acquired EPI resistance. The AGS/EPI cell subline developed by exposing parental AGS cells to stepwise increasing concentrations of EPI demonstrated 2.52-fold resistance relative to the AGS cell line, and mRNA expression of the ATP-dependent drug-efflux pump P-glycoprotein (Pgp), more recently known as ABCB1 protein, was similarly upregulated. An AGS/EPI cell subline could thus be effectively established, and MDR mechanism of these cells was shown to be related to the overexpression of mRNA of the ABCB1 gene.

BACKGROUND: Studies have demonstrated that some polymorphisms in diff erent interleukin genes may increase the risk of cancer. The aim of this study was to investigate the association between the IL-8 (rs4073) -251A/T gene polymorphism and the risk of gastric cancer (GC). PATIENTS AND METHODS: A case-control study was conducted on patients with noncardia gastric cancer. DNA was extracted from leukocytes and the IL-8 (rs4073) -251A/T polymorphism was analyzed by PCR-RFLP. Infection with Helicobacter pylori was investigated in the serum by ELISA. RESULTS: The sample consisted of 104 patients with GC and 196 controls. Cigarette smoking (P=0.007) and high fat intake (P=0.01) were more frequent in patients with GC.

Gastric cancer (GC) remains a virtually incurable disease when metastatic and requires early screening tools for detection of early tumor stages. Therefore, finding effective strategies for prevention or recurrence of GC has become a major overall initiative. RNA-interference (RNAi) is an innovative technique that can significantly regulate the expression of oncogenes involved in gastric carcinogenesis, thus constituting a promising epigenetic approach to GC therapy. This review presents recent advances concerning the promising biomolecular mechanism of RNAi for GC treatment.