RESUMEN
PURPOSE: Published data on the association between manganese superoxide dismutase (MnSOD) Val(16)Ala polymorphism and prostate cancer (PCA) risk are inconclusive. To derive a more precise estimate of the association between them, a meta-analysis was performed. METHODS: PubMed and Embase were searched. All eligible studies were retrieved. The pooled odds ratio (OR) with 95% confidence interval (CI) for PCA risk associated with Val/Ala versus Val/Val, Ala/Ala versus Val/Val, dominant model (Ala/Ala + Val/Ala vs. Val/Val), and recessive model (Ala/Ala vs. Val/Ala + Val/Val) were estimated, respectively. RESULTS: A total of 12 studies including 8,962 subjects were involved in this meta-analysis. Overall, the meta-analysis indicated that significantly elevated cancer risk was associated with Ala variant genotype when all the eligible studies were pooled into the meta-analysis (for Val/Ala vs. Val/Val: OR = 1.11, 95% CI = 1.00-1.24; for Ala/Ala vs. Val/Val: OR = 1.22, 95% CI = 1.00-1.49; for dominant model: OR = 1.14, 95% CI = 1.03-1.26). In the subgroup analysis by ethnicity, statistically significant increased risks were found among Caucasians with Ala allele (for Val/Ala vs. Val/Val: OR = 1.12, 95% CI = 1.00-1.25; for dominant model: OR = 1.14, 95% CI = 1.02-1.26). However, no significant associations were found in Africans. CONCLUSIONS: This meta-analysis suggests that the Ala allele of the MnSOD gene was a low-penetrance susceptible gene in PCA development, especially in Caucasians.
Asunto(s)
Predisposición Genética a la Enfermedad/genética , Polimorfismo de Nucleótido Simple/genética , Neoplasias de la Próstata/genética , Superóxido Dismutasa/genética , Genotipo , Humanos , MasculinoRESUMEN
Epidemiologic studies have evaluated the association between KRAS mutations and resistance to the treatment of epidermal growth factor receptor (EGFR) tyrosine-kinase inhibitors (TKIs) in patients with non-small cell lung cancer (NSCLC). However, results were inconclusive. To derive a more precise estimation of the relationship, we performed this meta-analysis. Systematic computerized searches of the PubMed and Medline databases (up to Jun 30, 2009) were performed. A total of 22 studies were included in the final meta-analysis, consisting of 1470 NSCLC patients, of whom 231 had KRAS mutations (16%). Current or former smokers had a higher frequency of KRAS mutations than never smokers (25% versus 6%; OR=4.36; P<0.01). Mutations were more common among adenocarcinoma than other histologies (26% versus 16%; OR=1.98; P<0.01). The objective response rate (ORR) of NSCLC patients with mutant KRAS was 3% (6/210), whereas the ORR of NSCLC patients with wild-type KRAS was 26% (287/1125). The overall pooled RR for ORR was 0.29 (95% CI: 0.18-0.47; P<0.01). Subgroup analyses were conducted on the basis of ethnicity and study treatment, all the results were not materially altered and did not draw different conclusions, indicating that our results were robust. In summary, this meta-analysis suggests that KRAS mutations may represent negative predictive biomarkers for tumor response in NSCLC patients treated with EGFR-TKIs. However, due to a mutually exclusive relationship between KRAS and EGFR mutation and no difference in survival between KRAS mutant/EGFR wild-type and KRAS wild-type/EGFR wild-type NSCLC, the clinical usefulness of KRAS mutation as a selection marker for EGFR-TKIs sensitivity in NSCLC is limited.