Constitutively decreased TGFBR1 allelic expression is a common finding in colorectal cancer and is associated with three TGFBR1 SNPs.
OBJECTIVE
Constitutively decreased TGFBR1 allelic expression is emerging as a potent modifier of colorectal cancer risk in mice and humans. This phenotype was first observed in mice, then in lymphoblastoid cell lines from patients with microsatellite stable colorectal tumors.


METHODS
We assessed the frequency of constitutively decreased TGFBR1 allelic expression and association with SNPs covering the TGFBR1 locus using RNA and DNA extracted from the peripheral blood lymphocytes of 118 consecutive patients with biopsy-proven adenocarcinoma of the colon or the rectum.


RESULTS
We found that 11(9.3%) of 118 patients exhibited decreased TGFBR1 allelic expression (TGFBR1 ASE). TGFBR1 ASE was strongly associated with three SNPs in linkage disequilibrium with each other: rs7034462 (p = 7.2 x 10-4), TGFBR1*6A (p = 1.6 x 10-4) and rs11568785 (p = 1.4 x 10-4).


CONCLUSIONS
These results confirm the high prevalence of constitutively decreased TGFBR1 allelic expression among patients with colorectal cancer. The association of this phenotype with TGFBR1*6A, rs7034462 and rs1156875 suggests an association between TGFBR1 SNPs and colorectal cancer, which warrants additional studies.
Pasche
Boris
B
Division of Hematology/Oncology, The University of Alabama at Birmingham and UAB Comprehensive Cancer Center, Birmingham, AL 35203, USA. boris.pasche@ccc.uab.edu
Wisinski
Kari B
KB
Sadim
Maureen
M
Kaklamani
Virginia
V
Pennison
Michael J
MJ
Zeng
Qinghua
Q
Bellam
Naresh
N
Zimmerman
Jacquelyn
J
Yi
Nengjun
N
Zhang
Kui
K
Baron
John
J
Stram
Daniel O
DO
Hayes
M Geoffrey
MG
D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D015153:Blotting, Western; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D003430:Cross-Sectional Studies; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011379:Prognosis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics*
D004273:DNA, Neoplasm; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D018125:Receptors, Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625841:TGFBR1 protein, human; C000625842:Tgfbr1 protein, mouse