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Cancer: a heavy word, and a filthy disease that we are sooner or later confronted with indirectly or directly. However, there is hope on the horizon, as early signs of cancer would appear for years or even decades before diagnosis, according to a large-scale study. That means that cancers could be treated much faster.
The new study is part of the “Pan-Cancer Analysis of Whole Genomes project” and is the most comprehensive study of cancer genetics ever. More than 1,000 scientists from 37 countries participated in the study, investigating more than 2,500 samples of tumors and 38 types of cancer. Thanks to their work, almost the complete genetic picture of all cancers was mapped.
Cancer genome
Cancer is caused by genetic mutations in what are initially healthy body cells. If those errors in the DNA are not detected by the body over time, it leads to the growth of cancer cells. These cancer cells make proteins themselves, so-called biomarkers, that can be detected in the blood and facilitate the diagnosis of cancer. However, the genetic instructions for making those proteins make up only 1% of the cancer genome.
With their research, the scientists have now gained insight into the other genetics of our body, so that various genetic changes can be detected earlier. After all, it appears that more than a fifth of the genetic mutations are already visible years to decades before the diagnosis, long before other signs of cancer. The genetic mutations can even take place in tissue that looks “normal” for the rest. This creates a longer “window of opportunity” in which patients can be tested and treated in the earliest stages of the disease.
New diagnoses
“If we can unravel the patterns of those early genetic mutations, it should now be possible to develop new diagnostic tests that pick up signals from cancer much faster,” said Peter Van Loo, co-lead author of the study in The Guardian. In addition, the number of patients diagnosed with a cell change leading to cancer could increase from two thirds to 95%. In one third of the patients, the doctors are currently in the dark about which cells have caused the cancer.
Detection in the blood
The study further discovered that about half of the earliest gene mutations occur in just nine genes. This means that the common gene pool that triggers cells to go from healthy to malignant is relatively small. Moreover, on average only 1 to 10 mutations would suffice for a healthy cell to develop into a cancer cell. In the future, it might be possible to detect those genetic mutations through so-called “liquid biopsies” – genetic tests that can pick up in the blood the DNA that causes tumors elsewhere. A scan or removal of tissue by surgery would then no longer be necessary.
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