The researchers at the University of Minnesota have discovered that the enzyme, called APOBEC3B is a broadly important cancer mutagen.
“We are very excited about this discovery because it indicates that a single enzyme is one of the largest known contributors to cancer mutation, possibly even eclipsing sources such as UV rays from the sun and chemicals from smoking,” lead author Reuben Harris said.
For the current study, Harris, along with colleagues Michael Burns and Alpay Temiz, analyzed tumor samples from 19 different types of cancer for the presence of APOBEC3B and 10 related proteins.
Results showed that APOBEC3B alone was significantly elevated in six types (bladder, cervix, two forms of lung cancer, head and neck, and breast).
Levels of the enzyme, which is present in low levels in most healthy tissues, were elevated in several other types of cancer as well.
A second key finding was that the mutational signature of APOBEC3B is a close match to the actual mutation pattern in these cancers.
Many cancer mutations have been identified, but discovering a common source of mutation such as APOBEC3B is expected to help researchers to move "upstream" and look for a way to stop carcinogenesis closer to its source.
The study was published in the July 14 issue of Nature Genetics.