Advances in genomic technologies and our understanding of genomics are changing the way we care for patients and families affected by cancer. Dr Clare Turnbull tells us how experts are using genomics to better care for patients.
How is genomics used in oncology?
Cancer is a genomic disease that occurs when changes in the DNA of a cell cause it to grow and divide uncontrollably. There are many reasons why this happens, and most cancers are a result of a number of DNA changes that occur, and are not corrected, in an individual cell. As the cell divides, these changes are passed on to daughter cells and to their daughter cells, and so on.
Genomics can be used in two ways in cancer care as we are dealing with two different genomes.
First there’s the genome of the patient, which is present in nearly every cell of an individual’s body. Some changes in this genome - known as ‘germline variants’ or ‘germline mutations’- can make an individual more susceptible to cancer. For example, a variation in the BRCA1 gene, which plays a role in DNA repair, significantly increases the risk of breast cancer. The management of patients and families with germline variants has traditionally been the realm of clinical geneticists.
Second, there’s the genome of the cancer. The majority of cancers are not due to an underlying, inherited predisposition, but are caused by spontaneous changes that occur in an individual cell. Spontaneous changes within a cell are known as ‘somatic variants’, ‘somatic mutations’, ‘acquired variants’ or ‘acquired mutations’, and some of them can lead to cancer. Experts can analyse these changes in cancer cells to provide a molecular diagnosis that can in many cases be used to guide treatment and management. For example, identification of an EGFR mutation in tumour cells increases the chances of a lung cancer responding to a drug called gefitinib. Those affected by cancer are managed by medical oncologists, who can often use this information to design a treatment plan for their patients.
Health Education England's Genomics Education Programme is developing a substantial education programme to inform healthcare professionals about the impact of genomics on clinical practice. This video is the one of the many educational resources from the programme.