Handwriting experts say that someone’s signature reveals a lot about their personality. Whether these analyses are “scientific” is debatable, but researchers in Ohio and New Hampshire have evidence that they’ve identified a signature of enhancer histone modifications that points to colon cancer.
Mono- and dimethylated H3K4 marks many classes of enhancers, so the team did a genome-wide comparison of these histone mods in colorectal cancer (CRC) and normal colon crypt cells, which are the cells in the colon that turn cancerous.
They identified thousands of sites that were differentially lost or gained in the CRC cells versus normal cells. These “variant enhancer loci” (VELs) make up 28-61% of CRC enhancers. Here’s what they learned:
- About 40% of gained VELs wind up with H3K27ac (a mark of an active enhancer) in CRC cells. Most of the lost VELs, however, have no detectable levels of H3K27ac in CRC cells, though that mod is present in the normal cells in those locations. DNaseI-sensitivity also changed.
- Some VELs were common to many CRC cell lines. A total of 197 were common to all nine CRC lines.
- Lost VELs were crypt-specific, and gained VELs weren’t. This suggests that in colon cancer, the enhancer marks change to make the cells have a less colon-specific phenotype.
- Lost VELs were more likely to have an effect on gene expression than gained VELs.
Also, the common VELs were present in primary tumors. The researchers say that this finding suggests that VELs are a signature of colon cancer.
Don’t sign anything before you read the fine print at Science Express, April 2012.