Update on clinical data combining capecitabine with targeted agents in newly diagnosed colorectal cancer

Association between the C3435T polymorphism of ABCB1/MDR1 gene (rs1045642) and colorectal cancer susceptibility : a meta-analysis based on 11,339 subjects

The association between ABCB1/MDR1 C3435T polymorphism and colorectal cancer has been evaluated. However, the results of these studies on the association remain inconsistent. To derive a more precise estimation of the relationship, a meta-analysis was performed. A comprehensive search was conducted to identify the eligible studies of ABCB1/MDR1 C3435T polymorphism and colorectal cancer risk. Summary odds ratios (OR) and 95 % confidence interval (CI) for ABCB1/MDR1 C3435T polymorphism and colorectal cancer were calculated. Statistical analysis was performed with the Stata (Version 12.0). Thirteen case-control studies, a total of 11,339 persons including 5,485 cases and 5,854 controls, met the included criteria and thus were selected. Collectively, the results of the present study suggest that there were no significant associations of ABCB1/MDR1 C3435T polymorphism with colorectal cancer observed for all comparison models. In the subgroup analysis, the same results were detected for both Caucasian and Asian populations. The results of this meta-analysis suggest that ABCB1/MDR1 C3435T polymorphism might be not related to colorectal cancer susceptibility.

The -149C>T polymorphism of DNMT3B is not associated with colorectal cancer risk: Evidence from a meta-analysis based on case-control studies

The aim of this study was to examine the association between the −149C>T polymorphism of DNA methyltransferase 3B (DNMT3B) and colorectal cancer (CRC) susceptibility. A comprehensive search was conducted to identify all case-control studies of the −149C>T polymorphism of DNMT3B and CRC risk. Statistical analysis was performed with the software program Stata (version 12.0) and Review Manager (version 5.0). A total of seven eligible studies, including 2,666 cases and 4,022 controls, associating the DNMT3B polymorphism of −149C>T with the risk of CRC were identified. These studies suggested no significant associations between the −149C>T polymorphism of the DNMT3B gene and the risk of developing CRC in the recessive, dominant and co-dominant models [for CC vs. TT: odds ratio (OR), 0.90; 95% confidence interval (CI), 0.90–1.25; P=0.37; for the recessive model: OR, 0.54, 95% CI, 0.28–1.04; P<0.00001; for the dominant model: OR, 1.07; 95% CI, 0.93–1.23; P=0.83 and C allele vs. T allele: OR, 0.70; 95% CI, 0.43–1.13; P<0.00001]. In the subgroup analysis, no significant associations were found in the European populations (for CC vs. TT: OR, 1.09; 95% CI, 0.92–1.30; P=0.88; for the recessive model: OR, 1.00; 95% CI, 0.88–1.13; P=0.14; for the dominant model: OR, 1.50; 95% CI, 0.89–2.54; P<0.00001 and C allele vs. T allele: OR, 0.70; 95% CI, 0.38–1.28; P<0.00001). No significant association was found between the −149C>T polymorphism in DNMT3B and CRC susceptibility.

Association of the DNMT3B polymorphism with colorectal adenomatous polyps and adenocarcinoma

DNMT3B is an important enzyme to modulate the methylation status in mammalian cells. The aim of this study is to investigate the correlation of the DNMT3B G39179T polymorphism with the susceptibilities of colorectal adenomatous polyps and adenocarcinoma. This case-control study included 146 colorectal adenomatous polyps, 170 colorectal adenocarcinoma patients, and 157 normal controls. DNMT3B polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism analysis. Family history of colorectal cancer significantly increases the risk of developing colorectal adenomatous polyps and adenocarcinoma. The genotype frequency of DNMT3B polymorphism (T/T and G/T + G/G) in adenocarcinoma patients was significantly different from that in controls (P value = 0.01). Compared with DNMT3B T/T genotype, the G allelotype (G/T + G/G genotype) had lower risk to develop colorectal adenocarcinoma (OR = 0.50, 95% CI = 0.29-0.87); while there was no significant difference between the colorectal adenomatous polyps patients and controls (OR = 0.63, 95% CI = 0.37-1.09), although descending tendency could be found in this polyps group. In the stratification analysis, a significant association was confined to subgroups of age < 55 (OR = 0.31, 95% CI = 0.12-0.84) and males (OR = 0.35, 95% CI = 0.17-0.71). Meanwhile, combined G/T + G/G genotypes were found to have a lower risk in non-drinkers to develop both colorectal adenomatous polyps and adenocarcinoma (OR = 0.54, 95% CI = 0.31-0.96 and OR = 0.48, 95% CI = 0.27-0.84, respectively). This study also showed a distinct difference in the distribution of DNMT3B G39179T SNP in different ethnics. DNMT3B G39179T SNP may be a potential genetic susceptibility factor for adenocarcinoma of the colon, especially in younger Chinese Han non-drinker men.

Concurrent diagnosis of Crohn's disease and colorectal carcinoma in a young man with abdominal pain

The lead time between diagnosis of Crohn's disease and presentation with a Crohn's related malignancy is generally twenty years from diagnosis. This case outlines that of a young man who presented to the emergency department with abdominal pain and was subsequently discovered to have a malignant stricture complicating underlying Crohn's disease that was previously quiescent and undiagnosed. It demonstrates that a new diagnosis of Crohn's disease does not rule out previously quiescent underlying disease and therefore risk of colrectal carcinoma.