Scientists at the Cancer Research UK Cambridge Institute at the University of Cambridge2 used traces of tumour DNA, known as circulating tumour DNA (ctDNA) found in cancer patients’ blood to follow the progress of the disease as it changed over time and developed resistance to chemotherapy treatments.
By looking for changes in the tumour ctDNA before and after each course of treatment, they were able to identify which changes in the tumour’s DNA were linked to drug resistance following each treatment session.
Using this new method they were able to identify several changes linked to drug-resistance in response to chemotherapy drugs such as paclitaxel (taxol) which is used to treat ovarian, breast and lung cancers, tamoxifen which is used to treat oestrogen-positive breast cancers and transtuzumab (Herceptin) which is used to treat HER2 positive breast cancers.
And they hope this will help shed new light on how cancer tumours develop resistance to some of our most effective chemotherapy drugs as well as providing an alternative to current methods of collecting tumour DNA – by taking a sample direct from the tumour – a much more difficult and invasive procedure.
Dr Nitzan Rosenfeld, Cancer Research UK funded scientist and one of the study authors, said: “Tumours are constantly changing and evolving which helps them develop a resistance to many of the drugs we currently give patients to treat their disease.
“We’ve shown that a very simple blood test can be used to collect enough tumour DNA to suggest to us what parts of the cancer’s genetic code is changing and creating tumour resistance to chemotherapy or biologically-targeted therapies.
“We hope that our discoveries can pave the way to helping us understand how cancers develop drug resistance as well as identifying new potential targets for future cancer drugs.”
Kate Law, director of clinical research at Cancer Research UK, said: “Research is helping us to find answers to one of cancers’ biggest questions – how tumours develop resistance to many of our most effective drugs.
“New techniques like this blood test, which offers a more personalised approach to treating cancers, will help us improve the effectiveness of treatments for patients.”
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1 Murtaza M et al, Noninvasive analysis of acquired resistance to cancer therapy by sequencing of plasma DNA (2013) Nature, DOI: 10.1038/nature12065v
Notes to editors
2 The study was directed by Dr James Brenton, Professor Carlos Caldas and Dr Nitzan Rosenfeld at the Cancer Research UK Cambridge Institute at the University of Cambridge.