As a term, “Cancer Research” covers a broad range of scientific investigation. Many of us think of cancer research as the development of new drugs to treat patients – known as drug discovery research – but this is only a part of the field as a whole. Alongside drug discover and research into the fundamental biology of cancer, there is a huge area of research into biomarkers.
Biomarkers are often genetic, protein or other kinds of molecular markers that can have a variety of uses. Firstly, biomarkers can be used to predict cancer risk: the most famous example of this may well be detection of BRCA1 mutation and the associated high risk of developing familial breast cancer. With regard to cancer diagnosis, the presence or absence of a particular molecule or molecules in say the blood or urine may indicate the presence of malignancy. Prostate Specific Antigen (PSA) is an example of such a marker. These markers may well be detectable long before we’d be able to see a tumour mass, and so allow for earlier detection of disease with the hope of improving survival outcome.
Biomarkers can also be used to monitor patients’ responses to treatments by, for example, looking for a decrease in a cancer-associated marker under a therapeutic regime. Similarly, the levels of such markers can be monitored after the end of therapy to look for early signs of relapse, again with the hope of catching cancers earlier to improve outcome. Again, PSA provides a good example of a marker that’s made its way from research right into the clinic – from bench to bedside.
Another way in which biomarkers can be useful is in predicting how well a patient will fare – these are known as prognostic biomarkers, as they are useful in predicting patient prognosis. In leukaemias, using techniques like FISH (fluorescence in situ hybridization) to identify abnormalities in the chromosomes of the patients is of prognostic value. Using molecular markers in this way allows for intensification of therapy in high risk disease cases to increase the chance of survival, but also allows scientists and clinicians to identify patients with low-risk disease. The low-risk patients may benefit from having a de-escalated therapeutic regime, as this less intense treatment could avoid many of the serious and often debilitating side effects of some kinds of cancer therapies.
Biomarkers can also be predictive of patients’ responses to particular therapies; these are becoming increasingly important as cancer treatment begins to move toward more targeted therapies which have fewer effects on non-cancerous tissues in the body, rather than relying on chemo- and radio-therapy which have many off-target effects (these off-target toxicities are the primary cause of therapy-associated late effects in cancer patients). An excellent example of this is looking for expression of the protein HER2 in breast cancers – if this marker is expressed then patient are likely to respond to the targeted therapy Herceptin, whereas patients’ whose cancers don’t express this molecule will not respond to the therapy. In this setting, assessing the status of HER2 expression is a biomarker for determining therapeutic regimes.
Without a doubt, biomarkers are a hugely useful tool when tackling cancer, and can often quickly be translated into a clinical setting to improve the lives of patients. This research is now being applied to a huge range of cancer types, and the majority of cancer patients will have had some form of biomarker assessment – whether to diagnose, aid prognosis, or determine an appropriate therapeutic regime with the hope of maximising patient survival and quality of life.
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Title picture ref: http://johnsonbanks.co.uk/thoughtfortheweek/research-kills-cancer/, with thanks to Cancer Research UK
FISH image: photo credit: wellcome images via photopin cc