Pharmacogenetics is the study of genetic differences that affect an individual’s response to drugs. It is the term that is used to focus on the influence of single genes on drug response.

Pharmacogenomics is a more comprehensive term that brings together pharmacology and genomics. It encompasses the finding that in some people, for some drugs, the way several genes may exert an effect can provide a better explanation of the variation in response to a drug. This knowledge can be used to help predict and tailor drug therapy. The wider array of genes is known as the genome.

The human genome was first ‘sequenced’ in 2003 and describes a complete set of gene sequences for a human, encoded as deoxyribonucleic acid (DNA).

Personalised medicine has been described as a move away from a one-drug-fits-all approach to the treatment and care of patients with a particular condition, to one which uses the person’s genetic information to target therapies to achieve the best outcomes in the management of their disease or predisposition to disease.

Cancer immunotherapy is where the genetic expression of a mutated cancer cell line can be used to develop treatment with a targeted therapy. In cancer, there is excessive, uncontrolled proliferation of abnormal cancer cells to form tumours (or in the blood, to cause leukaemias). To treat cancers with immunotherapy, antibodies are synthesised and directed at proteins or receptors on the cancer cell walls, or against enzymes, to disrupt or destroy the cancer. One of the earliest examples of cancer immunotherapy was trastuzumab (Herceptin) – an antibody developed to target the overexpression of the HER-2 receptor in some breast cancers and subsequently used in some other cancers.