Related Experiment Video
Updated: May 24, 2026

Candidate Gene Testing in Clinical Cohort Studies with Multiplexed Genotyping and Mass Spectrometry
Published on: June 21, 2018
A comparison of approaches for association studies of polymorphisms and colorectal cancer risk
S D Ramsey1, R S Holmes, C L McDermott
1Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA. sramsey@fhcrc.org
Aim:
Meta-analyses have been used to evaluate associations between polymorphisms and colorectal cancer risk, but the quality of individual studies used to inform them may vary substantially. Our aim was to apply well-established quality-control criteria to individual association studies and then compare the results of meta-analyses that included or excluded studies that did not meet these criteria.
Method:
We used meta-analyses of studies reporting a relationship between polymorphisms and colorectal cancer published between 1996 and 2008. Polymorphism-cancer associations were derived in separate meta-analyses including only those meeting the quality-control criteria.
Results:
Relative ORs varied substantially between the open and restricted group meta-analyses for all variants except MTHFR 677 CT. However, the associations were modest and the direction of relative risk did not change after applying criteria. Publication bias was detected for all associations, except the restricted set of studies for GSTP1 GG.
Conclusion:
We observed variation in calculated relative risk and changes in tests for publication bias that were dependent on the inclusion criteria used for association studies of polymorphisms and colorectal cancer. Standardizing study inclusion criteria may reduce the variation in findings for meta-analyses of gene-association studies of common diseases such as colorectal cancer.
Related Concept Videos
Genome-wide Association Studies-GWAS
GWAS does not require the identification of the target gene involved in...
Pharmacogenomics: Identification of New Drug Targets
Comparing Copy Number Variations and SNPs
Copy number variations or CNVs are the structural variations that cover more than 1kb of DNA sequence. The single nucleotide polymorphism (SNP), on the other hand, is a single nucleotide change or a point mutation that is found in more than 1%...
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Principles of Pharmacogenetics: Types of Genetic Variants
Single Nucleotide Polymorphisms-SNPs
