Lack of an association between the TGFBR1*6A variant and colorectal cancer risk.
OBJECTIVE
Recently a common variant of the TGFBR1 gene, TGFBR1*6A, has been proposed to act as a low-penetrance tumor susceptibility allele for colorectal cancer, but data from published studies with individually low statistical power are conflicting. To further evaluate the relationship between TGFBR1*6A and colorectal cancer risk, we have conducted a large case-control study and a meta-analysis of previously published studies.


METHODS
A total of 1,042 colorectal cancer cases and 856 population controls were genotyped for the TGFBR1*6A polymorphism. Previously published case-control studies of the relationship between TGFBR1*6A and colorectal cancer were identified, and a meta-analysis was conducted.


RESULTS
We found no evidence that homozygosity, heterozygosity or carrier status for the TGFBR1*6A allele confers an increased risk of colorectal cancer; respective odds ratios (OR) were 1.05 [95% confidence interval (95% CI), 0.83-1.32], 0.82 (95% CI, 0.34-1.99), and 0.92 (95% CI, 0.74-1.15), respectively. A meta-analysis of our case-control study and seven other studies that provided data on 2,627 colorectal cancer cases and 3,387 controls also yielded no evidence that possession of the TGFBR1*6A allele is associated with an elevated risk of colorectal cancer; pooled estimate of the OR were 1.20 (95% CI, 0.64-2.24) for homozygosity, 1.11 (95% CI, 0.96-1.29) for heterozygosity, and 1.13 (95% CI, 0.98-1.30) for carriers of TGFBR1*6A.


CONCLUSIONS
Current data provide limited support for the hypothesis that sequence variation in TGFBR1 defined by the TGFBR1*6A allele confers an elevated risk of colorectal cancer.
Skoglund
Johanna
J
Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
Song
Bo
B
Dalén
Johan
J
Dedorson
Stefan
S
Edler
David
D
Hjern
Fredrik
F
Holm
Jörn
J
Lenander
Claes
C
Lindforss
Ulrik
U
Lundqvist
Nils
N
Olivecrona
Hans
H
Olsson
Louise
L
Påhlman
Lars
L
Rutegård
Jörgen
J
Smedh
Kennet
K
Törnqvist
Anders
A
Houlston
Richard S
RS
Lindblom
Annika
A
D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics*; D012307:Risk Factors
D018125:Receptors, Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625841:TGFBR1 protein, human