Researchers at the Dana-Farber Cancer Research Institute have found further evidence linking meat consumption and colon cancer. This is reported in an article published in the journal Cancer Discovery.
Scientists sequenced the exome of colorectal carcinoma cancer cells. The exome is the part of the genome represented by exons, the regions that are directly involved in protein synthesis. A total of 900 cases of cancer in patients who were seen in the study were examined, linking the disease to lifestyle and diet.
The researchers found that the cancer cases were associated with a type of DNA damage called alkylation, which has not previously been described for colorectal carcinoma. The proto-oncogenes KRAS and PIK3CA were subjected to alkylation. KRAS encodes a protein that is involved in the transmission of signals related to the initiation of cell growth and division. In addition, it is widely known that mutations in PIK3CA are associated with the development of various human tumors.
The affected tissues were mainly located in the distal intestine, which leads to the rectum, where tumors most often develop. All of the identified mutations in the genes were also associated with poor patient survival. The most extensive levels of alkylation increased the risk of death from rectal cancer by 47 percent.
A similar mutational process was observed in healthy colon tissue, but in all cases, the researchers found an association with high levels of processed and unprocessed red meat consumption, but not with consumption of poultry, fish or other lifestyle factors studied. This is because meat contains chemicals that can cause alkylation, such as nitroso compounds.
According to the scientists, the results of the study will help develop methods to prevent cancer. For example, it may be possible to identify patients who have already begun to accumulate mutational signatures, and thus determine who is at greater risk of developing cancer or already has the disease at an early stage. The very understanding of the biological pathway through which diet can cause bowel cancer makes it possible to create drugs that prevent alkylation. The authors also recommend giving up red meat and eating a balanced diet.