This summer, a brand new drug trial to treat lung cancer is due to begin in the UK. The first of its kind, it aims to use the most up to date understanding of the genetics of cancerous tumours to help find drugs to treat patients with specific forms of lung cancer. Researchers in health services, universities and industry have been collaborating to locate genetic mutations in cancer cells so they can develop treatments to specifically target those mutations.
Cancer is caused when cells starts to grow ‘out of control’. Instead of dividing and becoming part of a normal tissue or organ, cancer cells continue to grow and divide so that they take over healthy tissue, forming a clump known as a tumour. Until recently cancers were defined by where they formed, breast cancer, lung cancer and so on, but now scientists are coming to understand that each cancer can be defined by its unique genetic and molecular make up. DNA and molecular profiling of tumours (similar to the profiles that are made during ‘DNA fingerprinting’ in forensic science) can reveal the changes that happen when cells transform from normal body cells into cancer cells.
The cost of of DNA sequencing is plummeting, but sequencing the entire genome of an individual’s cancer is still too expensive to be used in every case. Nevertheless tests can target the most important or clinically relevant genetic mutations, such as those in oncogenes, genes that normally suppress tumours. A range of different abnormalities have been identified and now, cancers that used to be thought of as one condition have been shown to have the same genetic variations in different patients, and the same mutations may be involved in widely different cancers. This exciting discovery means that a drug developed to target one type of cancer may also help patients with a completely different type of cancer that shares the mutation.
Understanding the genetics of cancerous cells means that treatments can be tailored to a particular patient and their cancer. This summer’s trial will look at potential treatments for patients with advanced lung cancer using small groups of patients who are likely to benefit from a certain drug. The drugs to be used have been developed by two huge pharmaceutical companies AstraZeneca and Pfizer, but perhaps in the future other pharmaceutical companies will allow their drugs libraries, which contain many other likely molecules, to be used in cancer trials too.
Lung cancer causes more deaths in the UK for men than any other cancer and is the second biggest killer of women. Worldwide around 1.6 million people a year die as a result of it. The risk of developing lung cancer is positively correlated to smoking as the mutagens (cancer causing chemicals) in tobacco smoke lead to mutations in the cells of the lungs. Although rates are declining in men, the number of women affected by lung cancer has increased over recent decades because of changes in smoking habits. The real key to beating the disease is to stop smoking but new treatments like genetic targeting may help those who are already affected.
As you study your IB course you will learn more about cell division (mitosis) and how cancerous tumours can develop. You’ll also find out about DNA profiling and the new advances in sequencing DNA and proteins. If you choose to study Option B you’ll discover how sequences are logged in huge databases that help researchers store and analyse information so that variations and changes can be found quickly and easily. Your teachers may also give you epidemiological data to analyse so that you can draw your own conclusions about the correlation between smoking and lung cancer and other health issues.