Understanding tumour markers
What are they? What's their role in cancer management? Kunal Kulkarni and colleagues help us pick out scientific fact amid media hype
A total of 153 397 people died from cancer in the UK in 2004. Worldwide, the number dying from cancer exceeded 6 million—12% of deaths. The World Health Organization (WHO) predicts that cancer rates could rise by 50% to 15 million newly diagnosed cases by the year 2020, which means that cancer will play an increasingly important role in all our careers.1
Despite the absence of established screening programmes, terms such as PSA are increasingly becoming publicly synonymous with cancer screening. Tumour markers are often branded among patients and doctors as “cancer blood tests”—direct signposts to cancer. Is this claim justified or is their role in cancer management a little different?
Tumour markers are proteins. As cancer is essentially the unregulated growth of normal tissue, both malignant and non-malignant tissues produce these proteins. This dramatically reduces their specificity and sensitivity as diagnostic tools.
A number of the commonly encountered markers