Estimating the Heritability of Colorectal Cancer

Hum Mol Genet. 2014 Jul 15;23(14):3898-905. doi: 10.1093/hmg/ddu087. Epub 2014 Feb 21.

Abstract

A sizable fraction of colorectal cancer (CRC) is expected to be explained by heritable factors, with heritability estimates ranging from 12 to 35% twin and family studies. Genome-wide association studies (GWAS) have successfully identified a number of common single-nucleotide polymorphisms (SNPs) associated with CRC risk. Although it has been shown that these CRC susceptibility SNPs only explain a small proportion of the genetic risk, it is not clear how much of the heritability these SNPs explain and how much is left to be detected by other, yet to be identified, common SNPs. Therefore, we estimated the heritability of CRC under different scenarios using Genome-Wide Complex Trait Analysis in the Genetics and Epidemiology of Colorectal Cancer Consortium including 8025 cases and 10 814 controls. We estimated that the heritability explained by known common CRC SNPs identified in GWAS was 0.65% (95% CI:0.3-1%; P = 1.11 × 10-16), whereas the heritability explained by all common SNPs was at least 7.42% (95% CI: 4.71-10.12%; P = 8.13 × 10(-8)), suggesting that many common variants associated with CRC risk remain to be detected. Comparing the heritability explained by the common variants with that from twin and family studies, a fraction of the heritability may be explained by other genetic variants, such as rare variants. In addition, our analysis showed that the gene × smoking interaction explained a significant proportion of the CRC variance (P = 1.26 × 10(-2)). In summary, our results suggest that known CRC SNPs only explain a small proportion of the heritability and more common SNPs have yet to be identified.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Case-Control Studies
  • Colorectal Neoplasms / epidemiology
  • Colorectal Neoplasms / genetics*
  • Genetic Predisposition to Disease
  • Genetic Variation
  • Genome-Wide Association Study
  • Humans
  • Models, Statistical*
  • Polymorphism, Single Nucleotide*
  • Quantitative Trait Loci
  • Smoking

Associated data

  • dbGaP/PHS000093V2.P2
  • dbGaP/PHS000206.V3.P2
  • dbGaP/PHS000207V.1P1