Allele-specific expression of TGFBR1 in colon cancer patients.
The genetic component of colorectal cancer (CRC) predisposition has been only partially explained. We recently suggested that a subtle decrease in the expression of one allele of the TGFBR1 gene was a heritable quantitative trait predisposing to CRC. Here, we refined the measurements of allele-specific expression (ASE) of TGFBR1 in a population-based series of CRC patients and controls. Five single-nucleotide polymorphisms (SNPs) in the 3'-untranslated region of the gene were genotyped and used for ASE determination by pyrosequencing. After eliminating non-informative samples and samples with RNA of insufficient quality 109 cases and 125 controls were studied. Allelic ratios ranged between 0.74 and 1.69 without evidence of bimodality or cutoff points for 'ASE' versus 'non-ASE'. Treating ASE as a continuous variable, cases had non-significantly different values than controls (P = 0.081 when comparing means by permutation test). However, cases had significantly higher ASE values when comparing medians by permutation test (P = 0.0027) and when using Wilcoxon test (P = 0.0094). We conclude that with the present-day technology, ASE differences between individuals and between cases and controls are too subtle to be used to assess CRC risk. More advanced technology is expected to resolve this issue as well as the low informativity caused by the limited heterozygosity of transcribed SNPs.
Tomsic
Jerneja
J
Human Cancer Genetics Program, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
Guda
Kishore
K
Liyanarachchi
Sandya
S
Hampel
Heather
H
Natale
Leanna
L
Markowitz
Sanford D
SD
Tanner
Stephan M
SM
de la Chapelle
Albert
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D003110:Colonic Neoplasms / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D019655:Quantitative Trait, Heritable; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics*
D018125:Receptors, Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625841:TGFBR1 protein, human