History and summary of cancer genetics
This page presents a brief history of genes and cancer, and a summary of genetic factors involved in the development of cancer.
A brief history of cancer genetics
Our understanding of the genetics underlying the development of cancer is increasing rapidly, and is translating into improvements in the prevention, detection and treatment of the disease.
Figure 1.1 shows some genetic landmarks in cancer research. adapted from 1,2
The timeline highlights some of the major milestones in our understanding of human genetics and its relevance to cancer. This knowledge developed slowly from the mid-19th century onwards. But in the last thirty years, there has been an explosion of knowledge about the molecular basis of cancer, and it is now recognised as being essentially a disease caused by mutation, or altered expression, of genes.
Cancer is not one single disease, but a complex group of around 200 diseases, characterised by uncontrolled cell division and the potential of the cells to invade surrounding tissues and spread around the body. These changes in cellular behaviour are the result of alterations in the function or levels of the proteins that control these processes. And these alterations are, in turn, usually caused by mutations, or changes in expression, of the genes encoding the proteins.
A summary of cancer genetics
The last few decades have brought an enormous and exciting expansion of knowledge about the genetic factors involved in the development of cancer.
There has been considerable progress in identifying the genes involved in both sporadic and familial cancers. In addition, it has been recognised that as well as genetic mutations, epigenetic changes and the interaction of genes with lifestyle factors play an important role in the development of cancer.
Identification of rare, high-risk genetic mutations responsible for familial cancers has lead to the availability of predictive genetic testing. As a consequence, access to genetic counselling, risk assessment and genetic testing is now widely available in family cancer clinics across the UK.
However, this knowledge and testing capability has brought with it the need to be able to use this knowledge to prevent these cancers developing. Although some preventative measures are available, more studies are needed to prove the true effectiveness of these measures.
At the research level, attention has largely shifted from the identification of rare high-risk genetic mutations to a hunt for lower risk gene polymorphisms, many of which are likely to be common within the population. The challenge is to identify these polymorphisms and to find strategies to reduce the risk of them contributing to cancer development.
In the longer term, identification of ‘genetic signatures’, combinations of mutations and other changes in gene expression associated with specific cancers, may allow genetic screening to become a means of cancer prevention in the general population. Identification of these gene polymorphisms may also result in a new batch of molecular targets on which to base tailored treatments and diagnostics.
A number of targeted agents are already being used and/or developed. These have shown varying levels of success in treatment, demonstrating the need to understand how different genetic changes interact with each other in order to optimise treatment, and also to investigate these agents in combinations.
The tangible benefits being gained from our increasing knowledge of the genetics of cancer are beginning to revolutionise the prevention, detection and treatment of the disease.
References
- Balmain, A.,Cancer genetics: from Boveri and Mendel to microarrays .Nat Rev Cancer, 2001. 1(1): p. 77-82
- Knudson, A.G., Two genetic hits (more or less) to cancer. Nat Rev Cancer, 2001. 1(2): p. 157-62
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