Journal of Cancer Prevention 2017; 22(1): 55-55
Published online March 30, 2017
© Korean Society of Cancer Prevention
Fahimeh Afzaljavan1,2, and Alireza Pasdar1,3
1Department of Modern Sciences and Technology, Mashhad University of Medical Sciences, Mashhad, Iran, 2Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran, 3Division of Applied Medicine, Medical School, University of Aberdeen, Aberdeen, UK
Correspondence to :
Alireza Pasdar, Department of Modern Sciences and Technology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran, Tel: +98-5138002310, E-mail: firstname.lastname@example.org
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
We read with interest the recently published systematic review and meta-analysis titled “The Evaluation of p53 Polymorphism at Codon 72 and Association With Breast Cancer in Iran: A Systematic Review and Meta-analysis”.1 We believe that there are few important issues in the systematic review and meta-analysis that require clarification. A key characteristic of a systematic review is a comprehensive search to find eligible studies. This study has been conducted between 2007 and 2014, however, one study has been missed.2 According to the date of publication, a study published in 2015 has also been missed.3 Furthermore, Hardy–Weinberg equilibrium (HWE) test is commonly used for quality control of genotyping and is one of the few ways to identify systematic genotyping errors.4 It seems that authors have not considered testing HWE for quality assessment of the included studies. Once we checked, the reported pooled data did not follow the HWE. Therefore, because of the lack of HWE analysis, the interpretation of these results may be difficult.
The appropriate sample size is a major issue in genetic case-control studies analyzing the association of polymorphisms with disease susceptibility. It seems the authors have also missed commenting on the statistical power in this study.
The random-effect method assumingly was used to measure association because of heterogeneity, but identifying the source of the heterogeneity could also be helpful to figure out the properties of those particular studies. Overall, we urge mentioning the missing data and also lack of quality control for the included studies to strengthen the conclusion reached by the authors.