Absence of association between N-acetyltransferase 2 acetylator status and colorectal cancer susceptibility: based on evidence from 40 studies.

BACKGROUND AND OBJECTIVES: N-Acetyltransferase (NAT) 2 is an important enzyme involved in the metabolism of different xenobiotics, including potential carcinogens, whose phenotypes were reported to be related to individual susceptibility to colorectal cancer (CRC). However, the results remain conflicting. To assess the relationship between NAT2 phenotypes and CRC risk, we performed this meta-analysis. METHODS: A comprehensive literature search was conducted to identify all case-control or cohort studies of NAT2 acetylator status on the susceptibility of CRC by searching of PubMed and EMBASE, up to May 20, 2011. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association. RESULTS: A total of over 40,000 subjects from 40 published literatures were identified by searching the databases. No significantly elevated CRC risk in individuals with NAT2 slow acetylators compared with fast acetylators was found when all studies pooled (OR = 0.95, 95% CI: 0.87-1.04, I(2) = 52.6%). While three studies contributed to the source of heterogeneity were removed, there was still null result observed (OR = 0.96, 95% CI: 0.90-1.03, P = 0.17 for heterogeneity, I(2) = 17.8%). In addition, we failed to detect any associations in the stratified analyses by race, sex, source of controls, smoking status, genotyping methods or tumor localization. No publication bias was observed in this study. CONCLUSIONS: This meta-analysis suggests that the NAT2 phenotypes may not be associated with colorectal cancer development.

[Expression of HER-2 and leptin in gastric cancer and their clinical significance].

OBJECTIVE: To assess the expression of HER-2 and leptin in gastric cancer and evaluate their relationship with VEGF expression and clinicopathological features, and their prognostic value for gastric cancer patients. METHODS: One hundred and ten gastric cancer specimens and the corresponding metastatic lymph nodes were detected for HER-2 by immunohistochemistry (IHC). All primary cancer tissues were detected for leptin, OB-Rb and VEGF. Ninty-six specimens of normal gastric mucosa served as the control. RESULTS: The expression level of HER-2, leptin and OB-Rb in gastric cancer tissues were significantly higher than those in normal tissues (19.1% vs. 8.0%, 49.1% vs. 34.0%, and 60.9% vs. 46.0%, P < 0.05). HER-2 overexpression was moderately homogenous in primary gastric cancer and matastatic lymph nodes (P = 0.607, Kappa = 0.581). There was a correlation between the expression of HER-2 and leptin, both of which were significantly correlated with tumor invasion depth, metastatic lymph nodes ratio (NR), distal metastasis, TNM stage and VEGF expression. However, there was no significant correlation between OB-Rb expression and the clinicopathological features evaluated. Cox regression multivariate analysis showed that tumor size, histological grade, NR, stage, chemotherapy and HER-2 expression were independent prognostic factors. CONCLUSIONS: HER-2 is stably expressed in primary gastric cancer and metastatic lymph nodes. HER-2 and leptin play an important role in the progression and angiogenesis of gastric cancer. High expression of HER-2 is a prognostic factor for poor outcome.