What is personalised medicine?

Personalised medicine means using information about a person and the condition they are diagnosed with to give treatment that will be as effective as possible.

Treatment for cancer is usually based on:

  • the type of cancer
  • its stage – the size of the cancer and whether it has spread
  • its grade – how slowly or quickly the cancer may grow.

Personalised medicine for cancer uses information about the person’s cancer cells. For example, tests on the cancer cells may show any of the following:

  • A hormone in the body is encouraging the cancer cells to grow. The cancer may then be treated with hormonal therapy drugs.
  • The cancer cells can avoid being found and destroyed by the body’s immune system. The cancer may then be treated with immunotherapy drugs.
  • The cancer cells have changes to certain genes. This is called the genetic make-up of the cancer. Genes are the instructions inside a cell that it needs to work properly. They are made up of a chemical called DNA. Some targeted therapy and immunotherapy drugs are only effective if the cancer cells have changes to certain genes.

This information helps healthcare professionals plan the best treatment for each person. As doctors and scientists learn more about genes and cancer, cancer treatment is likely to become more and more personalised. This should help people with cancer have the most effective and safest treatment for them.

Related pages

Information about genes and inherited cancer risk

On this page, we talk about how the genetic make-up of cancer cells can help doctors personalise a person’s treatment. We have separate information about how a person’s genetic make-up may affect their and their family’s risk of developing cancer.

Testing cancer cells (genomic or molecular testing)

Doctors can send a sample of cancer cells to a laboratory to be tested for specific gene changes. These tests are called genomic or molecular tests. They can also be called biomarker tests or panel tests.

Genomic testing looks for specific gene changes in cancer cells. This is not the same as looking for gene changes that may be passed from parent to child (inherited).

The sample may be a blood test. Or doctors may use cells from a biopsy or bone marrow biopsy you have already had. If your cancer has come back, your cancer doctor may ask you to have another biopsy. This is because certain features of the cancer may have changed.

Finding out about the gene changes in your cancer helps your doctors know which treatments may be most effective for you. It can also help doctors know which treatments are unlikely to help.

There are also tests called cytogenetic tests. These look at the pattern of chromosomes in a cell. Chromosomes are made up of genes. Some cancers have 1 or more abnormal chromosomes.

Other tests look for proteins inside or outside the cancer cell. These tests show whether the cancer cell is producing an abnormal protein or too much of a certain protein.

Liquid biopsies

A liquid biopsy is a blood sample. Doctors look for cancer cells in the blood. These are called circulating tumour cells (CTCs). They also look for DNA from cancer cells. This is called circulating tumour DNA (ctDNA).

A liquid biopsy can tell doctors more about the genetics of the cancer. Liquid biopsies are not common. But they may be used for some cancer types.

Getting test results

You may need to wait a few weeks to get the results of your tests. This can be a worrying time. You may worry you will not have the gene change needed to be able to have a certain targeted therapy or immunotherapy drug. If a certain drug is not suitable for you, your cancer doctor will usually talk to you about other possible treatment options.

Talking to a partner, family member or close friend can help. You can also talk to one of our cancer support specialists.

Personalised medicine and different cancers

Doctors already use a personalised approach to treating many different cancers. This will increase as more cancer drugs and tests become available.

We have included some examples of personalised medicine for different cancers below.

Breast cancer

If you are diagnosed with breast cancer, you will have tests on the cancer cells to see whether they produce the HER2 protein. If they do, the cancer is described as HER2 positive. Your doctors may recommend you have treatment with a targeted therapy drug. For early-stage breast cancer, you usually have trastuzumab. Some people also have pertuzumab.

Bowel cancer

If you have advanced bowel cancer, the cancer cells may be tested to look for changes in the RAS and BRAF genes. The results tell your doctors which treatments may work for you and which treatments will not help.

If you have a normal RAS gene and no changes to the BRAF gene, you may have treatment with the targeted therapy drugs cetuximab and panitumumab.

Other targeted therapies that can be used for bowel cancer include bevacizumab, ramucirumab and regorafenib.

Lung cancer

If you have non-small cell lung cancer that has spread, you might have treatment with targeted therapy or immunotherapy drugs.

You usually need to have tests on the cancer cells to find out whether a drug is suitable for you.

Your doctor may test the cancer cells to check for a change in the EGFR gene. If you have this gene change, your cancer doctor may give you: 

A small number of people with non-small cell lung cancer have a change in the ALK gene. If tests show the ALK gene change, your cancer doctor may give you:

Several immunotherapy drugs can be used to treat non-small cell lung cancer, including pembrolizumab and nivolumab. They target and block a protein called PD‑1 on the surface of T-cells. T-cells are part of the immune system. You may need tests on the cancer cells to check the level of PD-1.

Chronic myeloid leukaemia (CML)

Most people with chronic myeloid leukaemia (CML) have the Philadelphia chromosome and an abnormal gene called BCR-ABL1. The BCR-ABL1 gene causes the leukaemia cell to make too much of a protein called tyrosine kinase. The main treatment for CML is a targeted therapy drug called imatinib which blocks this protein. Other drugs called dasatinib and nilotinib are also used.


You may have targeted or immunotherapy drugs to treat melanoma that cannot be removed with surgery or that has spread (advanced melanoma). These treatments may sometimes be used after surgery to help reduce the risk of the cancer coming back.

If the melanoma cells have a change in the BRAF gene, you may have the following targeted therapies: 

Immunotherapy drugs are also used to treat melanoma. These include:

They target certain proteins found on T-cells. T-cells are part of the immune system. Ipilumumab targets a protein called CTLA-4. Nivolumab and pembrolizumab target the PD-1 protein. The drugs block these proteins and stimulate the immune system to destroy the melanoma cells.

About our information

  • References

    Below is a sample of the sources used in our personalised medicine information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    Al Bakir I, Sebepos-Rogers GM, Burton H, et al. Mainstreaming of genomic medicine in gastroenterology, present and future: a nationwide survey of UK gastroenterology trainees. BMJ Open 2019;9:e030505. doi:10.1136/ bmjopen-2019-030505 (accessed June 2022)

    Royal College of Physicians and British Pharmacological Society. Personalised prescribing: using pharmacogenomics to improve patient outcomes. Report of a working party. London: RCP and BPS, 2022. (accessed June 2022)

    NHS Genomic medicine service. https://www.england.nhs.uk/genomics (accessed June 2022)

    Piawah, S. and Venook, A.P. (2019), Targeted therapy for colorectal cancer metastases: A review of current methods of molecularly targeted therapy and the use of tumor biomarkers in the treatment of metastatic colorectal cancer. Cancer, 125: 4139-4147. https://doi.org/10.1002/cncr.32163 (accessed June 2022)

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Marc Tischkowitz, Reader and Honorary Consultant Physician in Medical Genetics.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 February 2023
Next review: 01 February 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.