Cancer Gene MapApprox Read Time: 5 minutes
- An international collaboration, Pan-Cancer Project involving 1,300 scientists has completed a decade-long project to map the many mutations that drive cancer’s development.
Basics: How Cancer is linked to gene mutation?
- Cancer is a disease of uncontrolled growth.
- The growth process, like all other physiological processes, has genetic controls so that the growth is self-limiting.
- When one or more genes malfunction, the growth process can go out of hand, leading to Cancer.
- One of the most common early changes in many cancers, including ovarian cancer, affects a gene called TP53.
- Breast cancer is associated with the BRCA 1 and BRCA 2 genes.
NOTE: Not just cancer, there are many other diseases with a genetic link in varying degrees.
News Summary: Cancer Gene Map
About the Research:
- A major international collaboration called the Pan-Cancer Analysis of Whole Genomes (PCAWG)/Pan-Cancer Project read the 47 million genetic changes in more than 2,500 tumors from 38 cancer types.
- This is the largest genome study ever of primary cancer.
- The research has revealed the most comprehensive gene map ever of the genes whose departures from normal behavior (mutations) trigger a cascade of genetic misbehavior that eventually lead to cancer.
- By analyzing the rate of mutations in tumors over time, they were able spot the critical moment where the genetic code changed significantly, further leading to cancer.
- The research shows genetic changes appear to have occurred many years before diagnosis, long before any other signs that a cancer may develop, and perhaps even in apparently normal tissue.
- The researchers identified 16 types of structural variation signatures in the genes ultimately leading to cancer.
- Structural variations mean deletion, amplification or reorganization of genomic segments that range in size from just a few bases to whole chromosomes. Bases are the structural units of genes.
- With aging in people, the cells in the body grow and divide, and errors are introduced into DNA.
- While most of these changes are harmless, and their effects largely controlled by the immune system, some cause the runaway growth of cells, and lead to tumors.
- These DNA errors continue to accumulate in cancerous cells, and those mutations form a timeline of the cancer’s history.
- By unlocking these patterns, it should now be possible to develop new diagnostic tests, that pick-up signs of cancer much earlier.
- Cancers of different parts of the body often behave very differently from one another. Thus, there is need to study various kinds of cancers separately.
- On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete.
Significance of the research:
- The PCAWG has discovered causes of previously unexplained cancers, pinpointed cancer-causing events and zeroed in on mechanisms of development, opening new vistas of personalized cancer treatment to strike at the root of the problem.
- The technique allows early detection (decades earlier than present diagnosis) of the cancer.
- For example: ovarian cancer can be seen up to 35 years before a woman would be diagnosed, while kidney, bladder, pancreatic skin and soft tissue could be seen nearly 20 years early.
- Likewise changes that lead to breast cancer could be spotted 15 years before tumors were noticed.
- It paves way for personalized cancer treatment that will slash the mortality rate of the world’s second-biggest killer i.e. Cancer.
- This could pave the way for a test (for example, with a blood test) which would warn people in time for treatment or lifestyle changes to be far more effective.