Ninety-eight percent of our genetic code does not carry out its main function: to code – and therefore “produce” – proteins (at least, this is what is thought today). This is why it has been called the dark matter of DNA. However, in recent years it is becoming increasingly clear that this huge amount of information has many other functions, and that if it is disrupted, it can have major consequences. Two related studies have just been published in the scientific journal Nature by a team of Canadian and Spanish researchers, coordinated by geneticists from the Ontario Institute for Cancer Research. The researchers identified a mutation, in the dark matter of DNA, which appears to be associated with different forms of brain, blood and liver tumors, which are among the most difficult to treat. Focusing on this mutation, with “targeted” therapies could become a new way to treat these types of cancer.
The mutation, called U1-snRNA, produces an error in the RNA, the molecule (a kind of template of DNA) that “directs” the assembly of proteins. The mechanisms are very complex but, to over-simplify it, we can say that this alteration to the RNA may interfere with the transcription of important blocks of genes, including those capable of triggering tumors (so-called “drivers”). The result is the creation of a sort of negative chain reaction in the genetic code and consequently an increased possibility of developing cancer.
“We’ve found that with one ‘typo’ in the DNA code the resultant cancers have hundreds of mutant proteins that we might be able to target using currently available immunotherapies” says Dr. Michael Taylor, one of the coordinators of the studies. However, the researchers also suggest that a different use of drugs already approved for other diseases may help, thanks to artificial intelligence systems.
The researchers examined tissue samples taken from patients with medulloblastoma (a neoplasm of the nervous system), chronic lymphocytic leukemia and hepatocellular carcinoma, but also based their findings on data from the “Pan-Cancer Analysis of Whole Genomes (PCAWG)” project: one of the largest coordinated cancer research endeavors, involving numerous groups of studies worldwide (gathered together in the International Cancer Genome Consortium), which to date has led to the analysis of more than 2800 genomes (the entire genetic code) of cancer cells, with the aim of identifying the mutations that trigger tumors.